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HomeMy WebLinkAboutCWMP Final Update Volume II Oct 2014 for Web_201410290730060538CWMPUpdate Appendices Volume II of II 225139 Town of Nantucket October 2014woodardcurran.com COMMITMENT &INTEGRITY DRIVE RESULTS 980 Washington Street Dedham, Massachusetts 02026 Nantucket (225139)i Woodard & Curran CWMP Update Appendices October 2014 APPENDICES Appendix A: MEPA Certificate 2004 CWMP Data 2004 Needs Areas Matrix Appendix B: Nantucket Zoning By-Law Board of Health Data Appendix C: Massachusetts Estuaries Report Summaries Massachusetts Estuaries Technical Memorandum on MOdel Run Scenarios total Maximum Daily Loads Landfill Backup Data Appendix D: Wannacomet Water Data Appendix E: Nantucket Sewer Act Board of Health Local Regulations Board of Health Administrative Consent Order Septic Management Plan Documents Appendix F: Wastewater Data Flows and Loads Calculations Appendix G: Madaket Wastewater Natural Heritage and Endnaged Species Appendix H: Surfside WWTF Data Capacity Analysis Technical Memorandum Energy Memo Groundwater Discharge Permit BRP -11 BRP – 83 O&M Manual Appendix I: Capital Improvements Plan Financing and Cost Scenarios Appendix J: Ocean Outfall Information Appendix K: Public Outreach Information Nantucket, MA (project #225139)Woodard & Curran CWMP Update September 2014 APPENDIX A: 2004 MEPA CERTIFICATE 2004 CWMP DATA 2004 NEEDS MATRIX TABLE 3D-2CWMP/EIRTOWN OF NANTUCKET, MASSACHUSETTSRATING CRITERIAYES NO7.333CRITERIA NAMEDESCRIPTIONMadaket Warren's Landing CiscoSomersetMiacometSurfside Tom Nevers Hi-DensityNumber Points Number Points Number Points Number Points Number Points Number Points Number PointsCRITERIA POINTSTotal Number of Lots86499204206127419350Actual Failure4 Total Number of Developed Lots43568143161101281255Imminent Failure3 Total Number of Unsewered Developed Lots43568143161101281255High Likelihood of Imminent Failure 2 Number of Resales since 3/31/9570192730154426Health / Water Quality Issue 1 Number of Acres per Study Area39449355151296685129Number of Net Acres for Developed Lots2322614310319736363No. of Acres of Severe Groundwater Limitation1171027784928Number of Acres of Severe Soil Limitation86261789614911261Actual Failure3/31/95 to 199931 124 4 16 8 32 21 84 8 32 21 84 2 81972 to 3/31/9574 296 2 8 10 40 8 32 6 24 27 1080105 420 6 24 18 72 29 116 14 56 48 192 2 8Adjusted Total based on Developed/Unsewered Developed Ratio 4202472116561928Imminent FailureSystem within Zone I Aquifer Recharge Area9 270 6 18 1 30 11 330System within 50 feet of Private Drinking Water Well0000000System within 100 feet of Public Drinking Water Supply0000000Developed Lots with Less than 10,000 sq. ft. of area per Bedro 260 780 66 198 105 315 152 45600 110 330269 807 66 198 111 333 153 459 0 0 11 33 110 330#High Likelihood of Imminent Failure Lots with Severe Groundwater Limitation130 260#14 28#11 22#816836320 40#54 108#Systems Built before 1978 (Title 5)281 562 1 2 43 86 13 26 15 30 72 144 2 4Lot Size less than or equal to 1/2 acre246 492 62 124 34 68 100 200 2 4 52 104 97 194Lots with Severe Soil Limitation95 190#36 72#72 144#103 206#51 102#46 92#121 242#Pumpouts Greater than 2 times per year0000000752 1,504 113 226 160 320 224 448 71 142 190 380 274 548#Health / Water Quality Issue2Density of Systems Greater Than 2 per Acre435 435#68 68#000161 161#000000255 255#1System within 100 feet of Surface Water Body, Wetlands or Streams 00 7 7 8 8 3 3 3 30System located within 100 Year Flood Plain53 530 660000System within Zone II Aquifer Recharge Area0000028280System within Harbor Watershed Line or 3,600' of Madaket Ha 435 435 34 3400000923 923 102 102 13 13 169 169 3 3 31 31 255 255Total Criteria Points for Study Area3,6545507381,1922016361,141Rating Criteria Points Per Developed Lot8.408.095.167.401.992.264.47RECOMMENDED AS A NEED AREAYESYESNOYESNONONO(Conventional Title 5 System Not Feasible for Majority of Study Area) TABLE 3D-2 (Continued)CWMP/EIRTOWN OF NANTUCKET, MASSACHUSETTSRATING CRITERIACRITERIA NAMEDESCRIPTIONom Nevers Lo-DensitySiasconsetQuidnetWauwinetPocomoPolpisTownNumber Points Number Points Number Points Number Points Number Points Number Points Number PointsCRITERIA POINTSTotal Number of Lots1951,04977681401004,741Actual Failure4 Total Number of Developed Lots122664455081593,943Imminent Failure3 Total Number of Unsewered Developed Lots12212745508159890High Likelihood of Imminent Failure 2 Number of Resales since 3/31/954827931110108Health / Water Quality Issue1 Number of Acres per Study Area6531,01268614575831,922Number of Net Acres for Developed Lots37434945512973951,333No. of Acres of Severe Groundwater Limitation312912229162324419Number of Acres of Severe Soil Limitation2864791991633711,076Actual Failure3/31/95 to 199913 52 3 12 7 28 3 12 6 24 10 40 43 1721972 to 3/31/9515 60 15 60 13 52 11 44 9 36 12 48 99 39628 112 18 72 20 80 14 56 15 60 22 88 142 568Adjusted Total based on Developed/Unsewered Developed Ratio 112376805660882,516Imminent FailureSystem within Zone I Aquifer Recharge Area0 2 60 28 84000System within 50 feet of Private Drinking Water Well0000000System within 100 feet of Public Drinking Water Supply0000000Developed Lots with Less than 10,000 sq. ft. of area per Bedroom 00 21 63 21 63 8 24 6 18 60 1800 0 2 6 21 63 49 147 8 24 6 18 60 180High Likelihood of Imminent Failure Lots with Severe Groundwater Limitation6 126191 382#15 30#24 48#29 58#33 66#859 1,718Systems Built before 1978 (Title 5)42 84 461 922 30 60 42 84 41 82 40 80 2,439 4,878Lot Size less than or equal to 1/2 acre37 74 512 1,024 22 44 8 16 8 16 10 20 3,098 6,196Lots with Severe Soil Limitation53 106#60 120#12 24#816829 58#38 76#498 996Pumpouts Greater than 2 times per year0000000138 276 1,224 2,448 79 158 82 164 107 214 121 242 6,894 13,788Health / Water Quality Issue2Density of Systems Greater Than 2 per Acre0 00127 127#000000000000890 890System within 100 feet of Surface Water Body, Wetlands or Str5 5 29 29 28 28 33 33 27 27 60 60 447 447System located within 100 Year Flood Plain2 2 1 1 1 1 13 13 8 8 16 16 65 65System within Zone II Aquifer Recharge Area0 13 130000161161System within Harbor Watershed Line or 3,600' of Madaket Harbor 000 50 50 81 81 59 59 1,972 1,9727 7 170 170 29 29 96 96 116 116 135 135 3,535 3,535Total Criteria Points for Study Area3953,00033046341448320,019Rating Criteria Points Per Developed Lot3.244.527.339.265.118.195.08RECOMMENDED AS A NEED AREANONOYESYESNOYESNO(Conventional Title 5 System Not Feasible for Majority of Study Area) TABLE 3D-2 (Continued)CWMP/EIRTOWN OF NANTUCKET, MASSACHUSETTSRATING CRITERIACRITERIA NAMEDESCRIPTIONTown - WPZ ShimmoMonomoyOtherNumber Points Number Points Number Points Number Points Number Points Number Points Number PointsCRITERIA POINTSTotal Number of Lots7432842632,539000Actual Failure4 Total Number of Developed Lots524137184818000Imminent Failure3 Total Number of Unsewered Developed Lots315137178812000High Likelihood of Imminent Failure 2 Number of Resales since 3/31/95372119114Health / Water Quality Issue1 Number of Acres per Study Area74488127621,863000Number of Net Acres for Developed Lots3133802185,422000No. of Acres of Severe Groundwater Limitation7171445,263000Number of Acres of Severe Soil Limitation3212301507,538000Actual Failure3/31/95 to 199923 92 9 36 17 68 60 2400001972 to 3/31/9524 96 17 68 30 120 110 44000047 188 26 104 47 188 170 680 0 0 0 0 0 0Adjusted Total based on Developed/Unsewered Developed Ratio 313104194685000Imminent FailureSystem within Zone I Aquifer Recharge Area000 10 30000System within 50 feet of Private Drinking Water Well0000000System within 100 feet of Public Drinking Water Supply0000000Developed Lots with Less than 10,000 sq. ft. of area per Bedro 137 411 33 99 37 1110000137 411 33 99 37 111 10 30 0 0 0 0 0 0High Likelihood of Imminent Failure Lots with Severe Groundwater Limitation5 10527 54#29 58#197 394#00000000Systems Built before 1978 (Title 5)74 148 40 80 108 216 337 674000Lot Size less than or equal to 1/2 acre229 458 4 8 29 58 73 146000Lots with Severe Soil Limitation136 272#36 72#97 194#280 560#00000000Pumpouts Greater than 2 times per year0000000444 888 107 214 263 526 887 1,774 0 0 0 0 0 0Health / Water Quality Issue2Density of Systems Greater Than 2 per Acre315 315#00000000000000000System within 100 feet of Surface Water Body, Wetlands or Str9 9 43 430 204 204000System located within 100 Year Flood Plain0 5 5 4 4 72 72000System within Zone II Aquifer Recharge Area473 473 3 3 116 116 117 117000System within Harbor Watershed Line or 3,600' of Madaket Harbor 0 103 103 184 184 161 161000797 797 154 154 304 304 554 554 0 0 0 0 0 0Total Criteria Points for Study Area2,4095711,1353,043000Rating Criteria Points Per Developed Lot4.604.176.173.720.000.000.00RECOMMENDED AS A NEED AREANONONONONONONO(Conventional Title 5 System Not Feasible for Majority of Study Area) Nantucket, MA (project #225139)Woodard & Curran CWMP Update September 2014 APPENDIX B: NANTUCKET ZONING BY-LAW 1 Town of Nantucket  OFFICE OF THE TOWN & COUNTY CLERK 16 Broad Street NANTUCKET, MASSACHUSETTS 02554-3590 Catherine Flanagan Stover, MMC, CMMC Town & County Clerk (508) 228-7216 FAX (508) 325-5313 Home: (508) 228-7841 Email:cstover@nantucket-ma.gov townclerk@nantucket-ma.gov WEBSITE:http://www.nantucket-ma.gov  2009 SPECIAL TOWN MEETING 2009 The following is a summary of the articles called, and the vote taken by the 2009 Special Town Meeting held at the Nantucket High School, Mary P. Walker Auditorium, 10 Surfside Road, on September 21, 2009. Monday, September 21st – Meeting called to order at 6:15 PM with 622 voters present. There were ultimately 774 voters present. At the close of Voter Registration there were 7632 voters. The Quorum Requirements for the meeting are 229 and 382. ______________________________________________________________ Article 1: Fiscal Year 2010 General Fund Operating Budget Adjustments (Not Called) Adopted by Unanimous Voice Vote [Quorum of 3% needed = 229] Article 2: Fiscal Year 2010 Enterprise Fund Operating Budget Adjustments (Not Called) Adopted by Unanimous Voice Vote Article 3: Appropriation: FY2010 Police and Fire Special Detail Fund (Not Called)Not Adopted by Unanimous Voice Vote [Quorum of 3% needed = 229] Article 4: Appropriation: Unpaid Bills (Not Called)Adopted by Unanimous Voice Vote [Quorum of 3% needed = 229] Article 5: Re-appropriation: Prior Year Articles (Not Called)Adopted by Unanimous Voice Vote [Quorum of 5% needed = 382] Article 6: Appropriation: Collective Bargaining Agreement/Laborer’s U*nion (Not Called) Adopted by Unanimous Voice Vote Article 7: Acceptance of Massachusetts General Law: Local Option Meals Tax (Called) Adopted by Handcount Vote: YES – 464; NO - 304 Article 8: Acceptance of Massachusetts General Law: Amend Local Room Occupancy Excise Tax (Called)Adopted by Handcount Vote: YES – 398; NO - 386 Article 9: Appropriation: Adult Community Day Care Program (Called)Positive Sense-of- the-Meeting Adopted by Voice Vote 2 Article 10: Zoning Bylaw Amendment: Assisted Living Community (ALC) District – Age Restriction (Called)Adopted by Declared 2/3 Majority Voice Vote Article 11: Zoning Bylaw Amendment: Assisted Living Community (ALC) District – Operating Entity (Called)Adopted by Declared 2/3 Majority Voice Vote Article 12: Zoning Bylaw Amendment: Assisted Living Community (ALC) District – Skilled Nursing (Not Called)Adopted by Unanimous Voice Vote Article 13: Zoning Bylaw Amendment: Assisted Living Community (ALC) District – Unit Ownership (Not Called)Adopted by Unanimous Voice Vote. Article 14: Zoning Bylaw Amendment: Assisted Living Community (ALC) District – Major Site Plan Review (Called)Adopted by Declared 2/3 Majority Voice Vote Article 15: Zoning Bylaw Amendment: Assisted Living Community (ALC) District – Affordable Housing (Not Called)Adopted by Unanimous Voice Vote Article 16: Zoning Bylaw Amendment: Definitions and Special Districts (Called, Call Withdrawn) Adopted as moved by Planning Board by Declared 2/3 Majority Voice Vote Article 17: Real Estate Disposition: Sherburne Commons (Called)Adopted by 2/3 Handcount Vote: YES – 517; NO – 134 2/3 = 434 Article 18: Zoning Map Change: Madaket RC to VTEC (Not Called)Adopted by Unanimous Voice Vote Article 19: Zoning Map Change: Madaket R-20 to LUG-3 (Not Called)Adopted by Unanimous Voice Vote Article 20: Zoning Map Change: Madaket R-20 to VR (Called)Adopted by Declared 2/3 Majority Voice Vote Article 21: Zoning Map Change: Madaket R-20 to LUG-1 (Not Called)Adopted by Unanimous Voice Vote Article 22: Zoning Bylaw Amendment: Height (Called)Adopted by Unanimous Voice Vote Article 23: Zoning Bylaw Amendment: Height Exemptions (Not Called)Not Adopted by Unanimous Voice Vote Article 24: Real Estate Conveyance: North Pasture (Not Called)Adopted by Unanimous Voice Vote Article 25: Real Estate Acquisition and Conveyance: North Pasture (Not Called)Adopted by Unanimous Voice Vote 3 Article 26: Real Estate Acquisition: Western Avenue (Called)Not Adopted by Handcount Vote: YES – 287; NO – 171 2/3 = 305 Article 27: Miller Lane Access (Not Called) “Moved that No Action Be Taken” by Unanimous Voice Vote Article 28: Appropriation Reduction: Police Station (Called)Not Adopted by Majority Voice Vote [Quorum of 5% needed = 382] Article 29: Size Reduction: Police Station (Called)Not Adopted by Declared 2/3 Majority Voice Vote. [Quorum of 5% needed = 382] Article 30: Bylaw Amendment: Town Meeting Quorum Requirement (Called)Not adopted by Majority Voice Vote Moved that the following articles be voted in accordance with the motions recommended by the Finance Committee or, in the absence of a Finance Committee motion, then in accordance with the motions as recommended by the Planning Board, as printed in the Finance Committee Report, with technical amendments brought forward during the course of the meeting: 1, 2, 3, 4, 5, 6, 7, 12, 13, 15, 18, 19, 21, 23, 24, 25, and 27. Moved, seconded, and Voted Unanimously. 2009 Special Town Meeting was dissolved at 10:17 PM, on September 21, 2009. A. [1]: B. (1) (2) (3) (4) (5) Town of Nantucket, MA Friday, September 5, 2014 Chapter 139. ZONING Article III. Use and Intensity Regulations § 139-7. Use chart; prohibited uses in all districts. [Amended 11-13-1990 STM by Art. 13, AG approval 3-19-1991; 5-5-1992 ATM by Arts. 37 and 51, AG approval 8-3-1992; 4-12-1994 ATM by Art. 53, AG approval 4-29-1994; 4-8-1996 ATM by Arts. 34, 35, and 36, AG approval 7-15-1996; 4-12-1999 ATM by Art. 33, AG approval 8-10-1999; 4-10-2000 ATM by Arts. 27 and 44, AG approval 8-2-2000; 1-8-2001 STM by Art. 5, AG approval 4-10-2001; 4-9-2001 ATM by Arts. 36, 37 and 38, AG approval 8-2-2001; 4-15-2003 ATM by Arts. 30, 31 and 49, AG approval 8-27- 2003; 4-4-2006 ATM by Art. 45, AG approval 8-2-2006; 4-11-2007 ATM by Art. 39, AG approval 6-28- 2007; 4-8-2008 ATM by Art. 64, AG approval 8-18-2008; 4-6-2009 ATM by Art. 27, AG approval 8-10- 2009] Use Chart.[1] Editor's Note: The Use Chart is included at the end of this chapter. Prohibited uses in all districts. Notwithstanding any other provisions of this chapter, the following uses shall be prohibited in all districts: More than two dwellings or dwelling units per lot except as otherwise allowed in this chapter. Use of a trailer or a building-like container for residential purposes or as a principal or accessory building or structure except as necessary for storage of chemicals and/or equipment by the Nantucket Fire Department. Use of a trailer or building-like containers as a temporary office or for construction materials storage (permitted only when incidental and accessory to construction actively underway on the same lot) longer than 12 months total. Any building or structure or any use of any building, structure or premises which is injurious, obnoxious, offensive, dangerous or a nuisance to the community or to the neighborhood through noise vibration, concussion, odors, fumes, smoke, gases, dust, harmful fluids or substances, danger of fire or explosion or other objectionable feature detrimental to the community or neighborhood health, safety, convenience, morals or welfare. A motor vehicle which is and for the immediately preceding thirty-day period has been disabled, dismantled or inoperative shall not be stored on any land or lot unless such Page 1 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 A. (1) (a) [1] [2] [3] [4] [5] vehicle is enclosed within a building or covered by a tarpaulin and screened from surrounding residential properties by a fence or hedge. § 139-8. Residential development options. [Amended 11-13-1990 STM by Art. 19, AG approval 3-19-1991; 4-12-1994 ATM by Art. 48, AG approval 4- 29-1994; 4-10-1995 ATM by Arts. 42 and 43, AG approval 5-22-1995; 4-9-2001 ATM by Art. 36, AG approval 8-2-2001; 4-15-2003 ATM by Art. 28, AG approval 8-27-2003; 4-12-2004 ATM by Arts. 35 and 36, AG approval 9-3-2004; 4-8-2008 ATM by Arts. 58, 59 and 64, AG approval 8-18-2008; 4-6-2009 ATM by Art. 27, AG approval 8-10-2009[1]; 4-6-2011 ATM by Arts. 63 and 64, AG approval 9-15-2011; 3-31 -2012 ATM by Art. 54, AG approval 7-12-2012] Flex development and open space residential development options shall become effective on January 1, 2013, and may be allowed as an alternative to a conventional subdivision. Flex development may be allowed in the Town O verlay District (TO D) through the issuance of a special permit by the Planning Board. O pen space residential development is allowed by-right in the Country O verlay District (COD). The primary purposes of these development options are as follows: (a) To allow for greater flexibility and creativity in the design of residential developments. (b)To encourage a more efficient form of development that consumes less open land. (c)To reduce infrastructure and site disturbance through the creation of compact development. (d)To encourage the permanent preservation of open space. Requirements. The following requirements shall apply to flex development and open space residential development: All plans shall conform to the requirements of MGLc. 41, §§ 81K through 81GG and the "Rules and Regulations Governing the Subdivision of Land," as may be amended by the Planning Board from time to time. Building lots shall not be subject to the regularity formula in § 139-16D . Building lots shall be restricted from any further lot division that results in additional building lots. To ensure that all common open space and common facilities within the development will be properly maintained, a homeowners' association shall be established in the form of a corporation, nonprofit organization, or trust. The homeowners' association legal documents shall be subject to approval by the Planning Board and shall be filed at the Nantucket County Registry of Deeds or the Registry District of the Land Court. Page 2 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 (b) [1] [a] [b] [c] [d] [2] [a] [b] [c] [d] [e] [f] [g] [h] [3] The maximum number of building lots, excluding any bonuses, shall not exceed the number which may otherwise have been created on a conventional subdivision plan meeting all dimensional and upland requirements of the Zoning Bylaw and in full conformance with (and requiring no waivers from) the "Rules and Regulations Governing the Subdivision of Land," as may be amended by the Planning Board from time to time, as demonstrated by the submission of a dimensioned lotting plan. Preservation of open space shall be required, with the amount based on the total tract size pursuant to Subsections A(3)and (4)below. A restriction defining the protection of the open space shall be enforceable by the Town or County of Nantucket and recorded at the Nantucket County Registry of Deeds or the Registry District of the Land Court. In addition, open space shall be: O wned by the Town of County of Nantucket; or O wned by the Nantucket Islands Land Bank; or Conveyed to an established nonprofit organization, a principal purpose of which is the conservation of open land; or Subject to a permanent conservation restriction, as provided in MGL c. 184, §§ 31 through 33, and owned in common by a corporation or trust composed of the owners of lots within the development. O pen space shall be restricted to one or more of the following uses, subject to approval of the Planning Board, in accordance with MGLc. 184, §§ 31 and 32: Preservation of important natural features on a lot. Passive recreation, including, but not limited to, nature study, boating, fishing, hunting, picnicking, and horseback riding. Active recreation. Bicycle paths and walking trails. Agriculture. Structures accessory to the use of the open space which may include, but are not limited to: boathouses, duck walks, landings, barns, gazebos. W ater features consistent with the purposes described above. Individual underground septic systems or wells that provide service to the lots within the development. Subject to Subsections A(3)and (4), a maximum of 50% of the required open space may be located on noncontiguous parcels of land in common ownership with the tract to be developed. The Planning Board shall determine the Page 3 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 [a] [b] [c] [d] [e] [f] (2) (a) [1] [2] [3] [4] (3) (a) [1] [2] [3] development potential of the noncontiguous parcel(s) and consider the open space value subject to the following criteria: Preservation of scenic views or vistas. Common border to existing open space. Existence of a fragile ecological environment. Agricultural importance. Importance to the community for recreation, water supply, cultural or historic municipal use. Importance to the community as determined by the Planning Board. Bonus lots. Flex developments and open space residential developments shall be entitled to bonus lots, subject to the requirements below. Bonus lots shall be based on the number of building lots which could have been created through a conventional subdivision plan, as set forth in § 139-8A(1)(a)[5]. For all density calculations that result in a fractional number, only fractions equal to or greater than 0.51 should be rounded to the next highest whole number. A 10% increase in the number of building lots that could have been created through the submission of a conventional subdivision plan. A 10% increase if the open space remains open to the public through a permanent access easement or conveyance to the Town or County of Nantucket or the Nantucket Islands Land Bank. A 1% increase for each 10% of the cluster lots restricted to a single dwelling unit, provided that the restricted lots would otherwise be permitted a second dwelling pursuant to Board of Health regulations. The total increase in building lots shall not exceed 30% of the number of building lots which could have been created through a conventional subdivision plan. Flex development. Flex development may be allowed in the Town O verlay District (TO D) through the issuance of a special permit subject to the following: The Planning Board shall be the sole special permit granting authority for relief pursuant to any provision of this chapter. Planning Board approval of a special permit shall not substitute for approval of a definitive subdivision or approval not required (ANR) plan. Flex Development shall be permitted in the R-40, R-20, R-10, R-5, and RO H Districts only and shall conform to the following dimensional requirements: Page 4 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 [4] [5] [6] [7] (b) [1] [2] [3] [4] (c) [1] [2] R-40 R-20 R-10 R-5 ROH Minimum tract area (acres) 5 3 2 1 1 O pen land required (total tract) 70% 50% 40% 30% 25% Minimum lot size (square feet) 10,0007,5004,0003,0003,000 Maximum lot ground cover ratio 35% 30% 50% 60% 65% Minimum frontage 20 20 20 0 0 Front setback 5 5 5 5 0 Side/Rear setback 5 5 5 5 0 The Planning Board may reduce, by up to 100% , the setbacks, provided that the Planning Board finds that such a change will not have an adverse impact on the neighborhood and that it will promote the purposes and intent of this section. The Planning Board may reduce, by up to 100% , the required frontage, provided that the lot has sufficient access through an easement. The Planning Board may waive the required minimum tract area, provided that the Planning Board finds that the proposed flex development is more in keeping with the surrounding area, promotes a more efficient use of land, and that it will promote the purposes and intent of this section. Noncontiguous open space parcels, subject to Subsection A(1)(b)[3], may be located in the Town O verlay District (TO D) or the Country O verlay District (CO D). The following development and design criteria will be considered by the Planning Board during its review of an application for flex development: Landscaping features utilizing natural or man-made materials are encouraged and may include effective screening, planting of street trees, and preservation of existing mature vegetation. Sidewalks and walking paths which encourage pedestrian activity are encouraged, including connections to adjacent neighborhoods and bordering open spaces. Vehicular access should be consolidated in a small number of widely spaced access points where practicable. Common driveways and shared parking areas are encouraged. The following performance criteria shall be reviewed by the Planning Board. Mitigation measures proposed by the developer shall be considered: Traffic flow and safety in the proposed development, the neighborhood, and adjacent public and private ways will not be significantly impacted in comparison with other development options; Page 5 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 [3] [4] (4) (a) [1] [2] [3] [4] [5] (b) (c) Quality of site design, building design (if applicable), and landscaping enhances the area in comparison with other development options; The provision of open land and any associated landscaping is appropriate for the scale and location of the development as determined by the Planning Board; That utilities and services, such as water and sewer, are adequate for the proposed development. Open space development. Open space development shall be allowed by-right within the Country Overlay District (COD), subject to the following: For parcels of land within an open space development, the Planning Board shall be the sole special permit granting authority for relief pursuant to any provision of this chapter. Open space development shall be permitted in the LUG-1, LUG-2, LUG-3, and VR Districts only and shall conform to the following dimensional requirements: LUG-3 LUG-2 LUG-1 VR Minimum tract area (acres) 10 10 5 3 Open land required (total tract) 80% 75% 65% 60% Minimum lot size (square feet) 10,000 10,000 10,000 10,000 Maximum lot ground cover ratio 20% 20% 20% 20% Minimum frontage 20 20 20 20 Front setback 15 15 15 15 Side/Rear setback 10 10 10 10 The Planning Board may issue a special permit to reduce, by up to 100%, the setbacks, provided that the Planning Board finds that such a change will not have an adverse impact on the neighborhood and that it will promote the purposes and intent of this section. Noncontiguous open space parcels, subject to Subsection A(1)(b)[3], may be located in the Country Overlay District (COD) only. In any LUG Zone, a minimum buffer of 50 feet of permanently restricted and undisturbed open space (excluding walking paths and fire access easements) shall be required between the proposed lot line of any open space residential development lot and the outside boundary of the subdivision tract. The Planning Board, through the issuance of a special permit, may reduce or waive this requirement if it finds that: Such reduction or waiver is necessitated by the shape or topography of the tract of land; or Natural resources will be better protected by an alternative location; or Page 6 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 (d) B. (1) (2) Equivalent protection against inconsistency with the existing pattern of development has been provided. Nantucket Housing Needs Program. Purpose. To create, make available and maintain housing that is affordable to people who earn less than 150% of the Nantucket County median household income; to maintain Nantucket's diversity and unique sense of community; to encourage moderate-income families to continue to reside on Nantucket; and to generate a supply of housing that will remain affordable. Definitions. The following definitions only apply to this § 139-8C: HOUSING AUTHORITY The Nantucket Housing Authority (NHA) or its designee. MAXIMUM RENTAL PRICE Shall be no more than the fair market rent established for Nantucket County as published by the U.S. Department of Housing and Urban Development in Federal Register, Vol. 65 No. 185 (September 25, 2000) and as may hereafter be amended from time to time. MAXIMUM RESALE PRICE The greater of the maximum sales price or price the current Nantucket Housing Needs Covenant unit owner paid for the Nantucket Housing Needs Covenant unit. MAXIMUM SALES PRICE Shall be calculated by assuming a ten-percent down payment and an annual debt service (at prevailing thirty-year fixed interest rates) that is equal to 30% of the gross annual income of a household earning up to 125% of median income. MEDIAN INCOME Median family income for Nantucket County as published from time to time by the U.S. Department of Housing and Urban Development. NANTUCKET HOUSING NEEDS COVENANT A covenant placed on housing, which property owners choose to execute and which shall be enforceable by the NHA, to be recorded in the Registry of Deeds or the Land Court Registry District. PRINCIPAL RESIDENCE The locality where a person resides with the present intent to make it the person's fixed and permanent home. The person's physical presence alone will not establish a principal residence. In ascertaining one's intent, the Housing Authority shall consider, among other things, the person's employment status, voter registration, driver's license, motor vehicle registration, real property ownership, income tax returns, or the filing with the Housing Authority of a written declaration to establish or maintain a principal residence. QUALIFIED PURCHASER HOUSEHOLD Page 7 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 (3) (a) [1] [2] [3] [4] [5] [6] (4) (a) (b) C. (1) (2) A household whose gross annual income is less than 150% of median income. QUALIFIED RENTER HOUSEHOLD A household whose gross annual income is not more than 100% of median income. General requirements. Housing subject to the Nantucket Housing Needs Covenant shall be: Occupied by a qualified renter or qualified purchaser household. The principal residence of the qualified renter or qualified purchaser household. Enforceable for the greater of 99 years or the maximum time period allowable by law. The price of the unit shall not exceed the maximum sales price, or, in the case of resale, the maximum resale price. The unit rent shall not exceed the maximum rental price. The owner of a unit being rented shall provide the Housing Authority with an annual certification of compliance with the terms of the covenant. Monitoring and administration. The Housing Authority shall monitor and administer the Nantucket Housing Needs Program and may promulgate rules and regulations to implement it. Prior to promulgating such rules and regulations and prior to completing a model Nantucket Housing Needs Covenant, the Housing Authority shall hold a public hearing or hearings to solicit advice from the public. The Housing Authority shall publish notice of these hearings prominently in a newspaper of general circulation on Nantucket for two successive weeks. All legal documentation shall be submitted to the Housing Authority for review and approval. Special permit to create secondary residential lots for year-round residents. Purpose: to create, make available and maintain housing that is affordable to those who earn at or below 150% of the Nantucket County median household income; to help those people or households to continue to reside on Nantucket if they wish to do so; to generate and preserve affordable housing in the Town of Nantucket in perpetuity, all in order to maintain Nantucket's diversity and unique sense of community. As authorized by MGL c. 40A, § 9, Paragraph 2, the Planning Board as special permit granting authority, in its discretion, pursuant to and subject to this § 139-8D, may issue a special permit, with conditions, authorizing the division of the original lot into a primary lot and a secondary lot, which special permit may include approval and endorsement of a plan not requiring approval under the Subdivision Control Law as such plan is defined and described in MGL c. 41, § 81P, provided the following requirements and/or conditions shall Page 8 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 (a) (b) (c) (d) (e) (f) (g) (h) apply to all applications for relief hereunder and all special permits granted hereunder, as the case may be: The original lot shall not be subject to any covenants, restrictions or similar encumbrances, whether appearing in a deed, easement, land-use permit or any other instrument, pertaining to the placement, use or occupancy of second dwellings on said original lot. The secondary lot shall be subject to an NHNC-Ownership Form, which shall provide, without limitation, that the owner of the secondary lot, and any occupant of any dwelling erected thereon, shall earn at or below 150% of the Nantucket County median household income. No more than one dwelling shall be permitted on the primary lot. No more than one dwelling shall be permitted on the secondary lot. The minimum area for the original lot, the primary lot and the secondary lot shall be as follows: Zoning District Minimum Original Lot Size (§ 139- 16A) Minimum Secondary Lot Size Minimum Primary Lot Size LUG-1 40,000 15,000 25,000 LUG-2 80,000 25,000 55,000 LUG-3 120,000 35,000 85,000 R-40 40,000 15,000 25,000 R-10 10,000 4,000 6,000 R-20/SR-20 20,000 8,000 12,000 VR 20,000 8,000 12,000 R-1/SR-1 5,000 2,000 3,000 ROH/SOH 5,000 2,000 3,000 RC 5,000 2,000 3,000 RC-2 5,000 2,000 3,000 LC 5,000 2,000 3,000 R-5 5,000 2,000 3,000 The primary lot and the secondary lot shall comply with the ground cover, front setback, side setback and rear setback requirements of the underlying zoning district, with the exception that the ground cover ratio solely for a secondary lot in the R-1 Zoning District shall be 36%. The Planning Board may waive the setback requirements only as they apply to the lot line(s) between the primary and secondary lot. The primary lot and the secondary lot each must have a minimum of 20 feet of frontage or an easement of sufficient width and grade to provide access. The primary lot and the secondary lot shall share a single driveway access. The Planning Board must be provided with an instrument, in recordable form, evidencing the common access rights to said access in accordance with this subsection. Page 9 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 (3) (4) (5) [1]: This § 139-8D shall not apply to major commercial developments (§ 139-11); cluster developments (§ 139-8A); major residential developments (§ 139-8B); and are not permitted in the following zoning districts: Commercial Downtown (CDT); Moorlands Management (MMD); Special Academy Hill (AHD); Special Our Island Home (OIH); and Assisted/Independent Living Community District (ALC). The Planning Board may grant a special permit for the division of a duplex into two attached single-family dwellings, provided that one of the dwellings is subject to a NHNC covenant. Subsection D(2)(e) and (f) above shall not apply and the Planning Board shall establish minimum lot size, ground cover ratio, and setbacks during the special permit review. Ground cover ratios for the primary and secondary lot combined shall not exceed the maximum allowed in the underlying zoning district. Section 139-16D, Regularity formula, shall not apply to this § 139-8D. Editor's Note: This enactment also repealed former § 139-8, Residential Districts R-1, R-10, SR-2 and ROH and Residential Commercial Districts RC, RC-2, CDT, CN, CTEC and LC, as amended. Page 10 of 10Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471615,11471875 Nantucket, MA (project #225139)Woodard & Curran CWMP Update September 2014 APPENDIX C: MASSACHUSETTS ESTUARIES REPORTS SUMMARIES MASSACHUSETTS ESTUARIES TECHNICAL MEMORANDUMS ON MODEL RUN SCENARIOS TOTAL MAXIMUM DAILY LOADS LANDFILL BACKUP DATA Executive Summary 1 Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Nantucket Harbor Nantucket, Massachusetts Executive Summary 1. Background This report presents the results generated from the implementation of the Massachusetts Estuaries Project’s Linked Watershed-Embayment Approach to the Nantucket Harbor embayment system, a coastal embayment of the Island of Nantucket within the Town of Nantucket, Massachusetts. Analyses of the Nantucket Harbor embayment system was performed to assist the Town with up-coming nitrogen management decisions associated with the Towns’ current and future wastewater planning efforts, as well as wetland restoration, anadromous fish runs, shell fishery, open-space, and harbor maintenance programs. As part of the MEP approach, habitat assessment was conducted on the embayment based upon available water quality monitoring data, historical changes in eelgrass distribution, time-series water column oxygen measurements, and benthic community structure. Nitrogen loading thresholds for use as goals for watershed nitrogen management are the major product of the MEP effort. In this way, the MEP offers a science-based management approach to support the Town of Nantucket resource planning and decision-making process. The primary products of this effort are: (1) a current quantitative assessment of the nutrient related health of the Nantucket Harbor embayment, (2) identification of all nitrogen sources (and their respective N loads) to embayment waters, (3) nitrogen threshold levels for maintaining Massachusetts Water Quality Standards within embayment waters, (4) analysis of watershed nitrogen loading reduction to achieve the N threshold concentrations in embayment waters, and (5) a functional calibrated and validated Linked Watershed-Embayment modeling tool that can be readily used for evaluation of nitrogen management alternatives (to be developed by the Town) for the restoration of the Nantucket Harbor embayment system. Wastewater Planning: As increasing numbers of people occupy coastal watersheds, the associated coastal waters receive increasing pollutant loads. Coastal embayments throughout the Commonwealth of Massachusetts (and along the U.S. eastern seaboard) are becoming nutrient enriched. The elevated nutrients levels are primarily related to the land use impacts associated with the increasing population within the coastal zone over the past half-century. The regional effects of both nutrient loading and bacterial contamination span the spectrum from environmental to socio-economic impacts and have direct consequences to the Massachusetts Department of Environmental Protection Executive Summary 2 culture, economy, and tax base of Massachusetts’s coastal communities. The primary nutrient causing the increasing impairment of our coastal embayments is nitrogen, with its primary sources being wastewater disposal, and nonpoint source runoff that carries nitrogen (e.g. fertilizers) from a range of other sources. Nitrogen related water quality decline represents one of the most serious threats to the ecological health of the nearshore coastal waters. Coastal embayments, because of their shallow nature and large shoreline area, are generally the first coastal systems to show the effect of nutrient pollution from terrestrial sources. In particular, the Nantucket Harbor embayment system within the Town of Nantucket is at risk of eutrophication (over enrichment) from enhanced nitrogen loads entering through groundwater from the increasingly developed watershed to this coastal system. Eutrophication is a process that occurs naturally and gradually over a period of tens or hundreds of years. However, human-related (anthropogenic) sources of nitrogen may be introduced into ecosystems at an accelerated rate that cannot be easily absorbed, resulting in a phenomenon known as cultural eutrophication. In both marine and freshwater systems, cultural eutrophication results in degraded water quality, adverse impacts to ecosystems, and limits on the use of water resources. The relatively pristine nature of Nantucket's nearshore and Harbor waters has historically been a valuable asset to the island. However, concern over the potential degradation of Harbor water quality began to arise, which resulted in monitoring, scientific investigations and management planning which continues to this day. Nantucket Harbor is one of the largest enclosed bays in southeastern Massachusetts and one of the few with a relatively high water quality capable of supporting significant high quality ecological habitats, such as eelgrass beds, and sustain a scallop fishery. Ironically, it is the pristine nature of this system which may indirectly threaten its ecological health as the coastal waters throughout Southeastern New England become increasingly degraded and the pressure for access and development of remaining high quality environments increases. The Town of Nantucket and work groups have long ago recognized that a rigorous scientific approach yielding site-specific nitrogen loading targets was required for decision-making, alternatives analysis and ultimately, habitat protection. The completion of this multi-step process has taken place under the programmatic umbrella of the Massachusetts Estuaries Project, which is a partnership effort between all MEP collaborators and the Town. The modeling tools developed as part of this program provide the quantitative information necessary for the Towns’ nutrient management groups to predict the impacts on water quality from a variety of proposed management scenarios. Nitrogen Loading Thresholds and Watershed Nitrogen Management: Realizing the need for scientifically defensible management tools has resulted in a focus on determining the aquatic system’s assimilative capacity for nitrogen. The highest-level approach is to directly link the watershed nitrogen inputs with embayment hydrodynamics to produce water quality results that can be validated by water quality monitoring programs. This approach when linked to state- of-the-art habitat assessments yields accurate determination of the “allowable N concentration increase” or “threshold nitrogen concentration”. These determined nitrogen concentrations are then directly relatable to the watershed nitrogen loading, which also accounts for the spatial distribution of the nitrogen sources, not just the total load. As such, changes in nitrogen load from differing parts of the embayment watershed can be evaluated relative to the degree to which those load changes drive embayment water column nitrogen concentrations toward the “threshold” for the embayment system. To increase certainty, the “Linked” Model is independently calibrated and validated for each embayment. Executive Summary 3 Massachusetts Estuaries Project Approach: The Massachusetts Department of Environmental Protection (DEP), the University of Massachusetts – Dartmouth School of Marine Science and Technology (SMAST), and others including the Cape Cod Commission (CCC) have undertaken the task of providing a quantitative tool to communities throughout southeastern Massachusetts (the Linked Watershed-Embayment Management Model) for nutrient management in their coastal embayment systems. Ultimately, use of the Linked Watershed-Embayment Management Model tool by municipalities in the region results in effective screening of nitrogen reduction approaches and eventual restoration and protection of valuable coastal resources. The MEP provides technical guidance in support of policies on nitrogen loading to embayments, wastewater management decisions, and establishment of nitrogen Total Maximum Daily Loads (TMDLs). A TMDL represents the greatest amount of a pollutant that a waterbody can accept and still meet water quality standards for protecting public health and maintaining the designated beneficial uses of those waters for drinking, swimming, recreation and fishing. The MEP modeling approach assesses available options for meeting selected nitrogen goals that are protective of embayment health and achieve water quality standards. The core of the Massachusetts Estuaries Project analytical method is the Linked Watershed-Embayment Management Modeling Approach, which links watershed inputs with embayment circulation and nitrogen characteristics. The Linked Model builds on well-accepted basic watershed nitrogen loading approaches such as those used in the Buzzards Bay Project, the CCC models, and other relevant models. However, the Linked Model differs from other nitrogen management models in that it: • requires site-specific measurements within each watershed and embayment; • uses realistic “best-estimates” of nitrogen loads from each land-use (as opposed to loads with built-in “safety factors” like Title 5 design loads); • spatially distributes the watershed nitrogen loading to the embayment; • accounts for nitrogen attenuation during transport to the embayment; • includes a 2D or 3D embayment circulation model depending on embayment structure; • accounts for basin structure, tidal variations, and dispersion within the embayment; • includes nitrogen regenerated within the embayment; • is validated by both independent hydrodynamic, nitrogen concentration, and ecological data; • is calibrated and validated with field data prior to generation of “what if” scenarios. The Linked Model Approach’s greatest assets are its ability to be clearly calibrated and validated, and its utility as a management tool for testing “what if” scenarios for evaluating watershed nitrogen management options. For a comprehensive description of the Linked Model, please refer to the Full Report: Nitrogen Modeling to Support Watershed Management: Comparison of Approaches and Sensitivity Analysis, available for download at http://www.state.ma.us/dep/smerp/smerp.htm. A more basic discussion of the Linked Model is also provided in Appendix F of the Massachusetts Estuaries Project Embayment Restoration Guidance for Implementation Strategies, available for download at http://www.state.ma.us/dep/smerp/smerp.htm. The Linked Model suggests which management solutions will adequately protect or restore embayment water quality by enabling towns to test specific management scenarios and weigh the resulting water quality impact against the cost of that approach. In addition to the management scenarios modeled for this report, the Linked Model can be used to evaluate additional management scenarios and may be Executive Summary 4 updated to reflect future changes in land-use within an embayment watershed or changing embayment characteristics. In addition, since the Model uses a holistic approach (the entire watershed, embayment and tidal source waters), it can be used to evaluate all projects as they relate directly or indirectly to water quality conditions within its geographic boundaries. Unlike many approaches, the Linked Model accounts for nutrient sources, attenuation, and recycling and variations in tidal hydrodynamics and accommodates the spatial distribution of these processes. For an overview of several management scenarios that may be employed to restore embayment water quality, see Massachusetts Estuaries Project Embayment Restoration Guidance for Implementation Strategies, available for download at http://www.state.ma.us/dep/smerp/smerp.htm. Application of MEP Approach: The Linked Model was applied to the Nantucket Harbor embayment system by using site-specific data collected by the MEP and water quality data from the Water Quality Monitoring Program conducted by the Nantucket Marine Department, with technical guidance from the Coastal Systems Program at SMAST (see Section II). Evaluation of upland nitrogen loading was conducted by the MEP. Estuaries Project staff obtained digital parcel and tax assessors data from the Town of Nantucket Geographic Information Systems Department, watershed specific water use data from the Wannacomet Water Company (WWC) and watershed boundaries adopted by the town as the Harbor Watershed Protection District (http://www.nantucket-ma.gov). During the development of the Nantucket Water Resources Management Plan, an island-wide groundwater mapping project, using many of the USGS wells on the Island, was completed to characterize the water table configuration of Nantucket (Horsley, Whittan, Hegeman, 1990). Estuary watershed delineations completed in areas with relatively transmissive sand and gravel deposits, like most of Cape Cod and the Islands, have shown that watershed boundaries are usually better defined by elevation of the groundwater and its direction of flow, rather than by land surface topography (Cambareri and Eichner 1998, Millham and Howes 1994a,b). This approach was used by Horsley, Whittan and Hegeman, Inc. (HWH) to complete a watershed delineation for Nantucket Harbor (Section III); this watershed delineation was been largely confirmed by subsequent water table characterizations (e.g., Lurbano, 2001, Gardner and Vogel, 2005). MEP staff compared the HWH Harbor watershed to a 2004 aerial base map. This comparison found some slight discrepancies likely based on a better characterization of the shoreline; changes were made based on best professional judgment and watershed/water table characterization experience in similar geologic settings The land-use data obtained from the Town was used to determine watershed nitrogen loads within the Nantucket Harbor embayment system and each of the systems sub- embayments as appropriate (current and build-out loads are summarized in Section IV). Water quality within a sub-embayment is the integration of nitrogen loads with the site-specific estuarine circulation. Therefore, water quality modeling of this tidally influenced estuary included a thorough evaluation of the hydrodynamics of the estuarine system. Estuarine hydrodynamics control a variety of coastal processes including tidal flushing, pollutant dispersion, tidal currents, sedimentation, erosion, and water levels. Once the hydrodynamics of the system was quantified, transport of nitrogen was evaluated from tidal current information developed by the numerical models. A two-dimensional depth-averaged hydrodynamic model based upon the tidal currents and water elevations was employed for the Nantucket Harbor embayment system. Once the hydrodynamic properties of the estuarine system were computed, two-dimensional water quality model simulations were used to predict the dispersion of the nitrogen at current loading rates. Using standard dispersion relationships for estuarine systems of this type, the water quality model and the hydrodynamic model was then integrated in order to generate estimates Executive Summary 5 regarding the spread of total nitrogen from the site-specific hydrodynamic properties. The distributions of nitrogen loads from watershed sources were determined from land-use analysis. Boundary nutrient concentrations in Nantucket Sound source waters were taken from water quality monitoring data. Measurements of current salinity distributions throughout the estuarine waters of the Nantucket Harbor embayment system was used to calibrate the water quality model, with validation using measured nitrogen concentrations (under existing loading conditions). The underlying hydrodynamic model was calibrated and validated independently using water elevations measured in time series throughout the embayments. MEP Nitrogen Thresholds Analysis: The threshold nitrogen level for an embayment represents the average water column concentration of nitrogen that will support the habitat quality being sought. The water column nitrogen level is ultimately controlled by the watershed nitrogen load and the nitrogen concentration in the inflowing tidal waters (boundary condition). The water column nitrogen concentration is modified by the extent of sediment regeneration. Threshold nitrogen levels for the embayment systems in this study were developed to restore or maintain SA waters or high habitat quality. High habitat quality was defined as supportive of eelgrass and infaunal communities. Dissolved oxygen and chlorophyll a were also considered in the assessment. The nitrogen thresholds developed in Section VIII-2 were used to determine the amount of total nitrogen mass loading reduction required for restoration of eelgrass and infaunal habitats in the Nantucket Harbor system. Tidally averaged total nitrogen thresholds derived in Section VIII.1 were used to adjust the calibrated constituent transport model developed in Section VI. Watershed nitrogen loads were sequentially lowered, using reductions in septic effluent discharges only, until the nitrogen levels reached the threshold level at the sentinel station chosen for the Nantucket Harbor system. It is important to note that load reductions can be produced by reduction of any or all sources or by increasing the natural attenuation of nitrogen within the freshwater systems to the embayment. The load reductions presented below represent only one of a suite of potential reduction approaches that need to be evaluated by the community. The presentation is to establish the general degree and spatial pattern of reduction that will be required for protection/restoration of this nitrogen threatened embayment. The Massachusetts Estuaries Project’s thresholds analysis, as presented in this technical report, provides the site-specific nitrogen reduction guidelines for nitrogen management of the Nantucket Harbor embayment system in the Town of Nantucket. Future water quality modeling scenarios should be run which incorporate the spectrum of strategies that result in nitrogen loading reduction to the embayment. The MEP analysis has initially focused upon nitrogen loads from on-site septic systems as a test of the potential for achieving the level of total nitrogen reduction for restoration of the embayment system. The concept was that since septic system nitrogen loads generally represent 28% - 53% of the controllable watershed load to the Nantucket Harbor embayment system and are more manageable than other of the nitrogen sources, the ability to achieve needed reductions through this source is a good gauge of the feasibility for protection/restoration of the system. 2. Problem Assessment (Current Conditions) A habitat assessment was conducted throughout the Nantucket Harbor system based upon available water quality monitoring data, historical changes in eelgrass distribution, time- series water column oxygen measurements, and benthic community structure. At present, the Nantucket Harbor System is showing variations in nitrogen enrichment among its 4 principal component basins. The inner basins of Head of the Harbor and Polpis Harbor are nitrogen Executive Summary 6 enriched over Quaise and the Town basins. Although the component basins of the Nantucket Harbor System are clearly enriched in nitrogen over the adjacent Nantucket Sound waters, the enrichment is relatively small, generally <0.100 mg L-1 (see Chapter VI). The effect of nitrogen enrichment is to cause oxygen depletion; however, with increased phytoplankton (or epibenthic algae) production, oxygen levels will rise in daylight to above atmospheric equilibration levels in shallow systems (generally ~7-8 mg L-1 at the mooring sites). Overall, oxygen within the Harbor bottom waters appears to remain at ecologically healthy levels, except for periodic oxygen depletion within the deepest portions of the Quaise and Wauwinet basins. However, as there were some oxygen depletions below 5 mg L-1 in the main basins (although infrequent), it appears that the system is at or just beyond it ability to assimilate additional nitrogen/organic matter. Within the highly flushed and generally well mixed waters of the lower basins of Nantucket Harbor, bottom waters were well oxygenated (>6mg L-1). The few excursions below 6 mg L-1 were isolated events, rather than a prolonged depletion such as generally associated with a phytoplankton bloom. However, these variations were small and overall the oxygen conditions are consistent with the observations of healthy infaunal and eelgrass communities. While Polpis Harbor also exhibited well oxygenated conditions, larger diurnal variations were recorded than in the outer basins. The higher diurnal fluctuations indicate waters supporting higher phytoplankton biomass. Quaise basin showed both significant diurnal oxygen fluctuations and an overall oxygen decline, although not to levels of high stress. There was a single "event" of a few days when each night oxygen levels reached 4 mg/L, but returned to ~5 mg L-1 each following day. Since the meter was located deeper within the basin (~6 m), oxygen levels throughout most of the basin area were almost certainly higher given their shallower depths, only in the "deep hole" was oxygen depletion likely greater. Assessing oxygen conditions within the Quaise basin indicates generally non-stressful oxygen levels, except for the deep basin. However, it is likely that the presence of the deep hole (~30') creates a geomorphological (natural) cause of the low dissolved oxygen. Head of the Harbor showed generally high oxygen levels. As in the Quaise basin, the meter was deeper in the basin and observed oxygen depletions were greater than experienced by bottom waters throughout most of the basin area. The oxygen conditions are consistent with the observed distribution of habitat quality throughout the Harbor System, with the deep waters showing oxygen depletion, but with oxygen levels generally supportive of a high habitat quality for infauna. However, since the system does show oxygen levels less than full atmospheric saturation, additional organic matter loads, (e.g. through nitrogen inputs) will likely increase the magnitude and frequency of the oxygen declines, again indicating a system at or just beyond its nitrogen assimilative capacity (nitrogen threshold) Based upon all available data it appears that eelgrass is presently a widespread critical habitat within the Nantucket Harbor System. The present distribution of eelgrass results from recolonization of the Harbor from its loss in the 1930's. A map of eelgrass from the 1940's "shows it to be primarily confined to parts of the Jetties and Horse shed at the Harbor entrance (Kelley 1989). Kelley (1989) concluded that from the 1960's to 1989, "eelgrass distribution has been relatively stable in Nantucket Harbor...". However, it is clear that eelgrass beds have been lost from this System. Both the MassDEP analysis and the direct observations of Kelley in 1989 indicated that there has been measurable eelgrass loss. The primary locations are within Head of the Harbor and East Polpis Harbor. The other major region experiencing gradual losses, the marginal areas of Head of the Harbor, is supported by both Kelley (1989) and the MassDEP survey data. This larger areal loss appears to be gradual and occurring primarily in the least well flushed areas of this basin (note the counterclockwise circulation). Eelgrass loss has also been noted to the west of Pocomo, which was observed in the 1980 surveys and more recently Executive Summary 7 in changes from 1995-2001. It is important to note that the eelgrass bed loss is both from the shallow area of the upper and mid regions of Head of the Harbor (<8' depth) and from the "deeper" areas (8'-12') in the lower reach and from the shallow east basin of Polpis. The data indicate that that on the order of 1000 acres of eelgrass habitat within the Nantucket Harbor System is impaired. It is important to note that the nitrogen levels throughout the Nantucket Harbor System remain relatively low, consistent with the observed oxygen conditions, lack of macroalgae and chlorophyll a levels. However, due to the water depth in the Harbor, it is possible that vertical and horizontal mixing rates appear to have resulted in a decline in eelgrass bed coverage from the deeper areas and more enclosed basin areas. Macro-algal abundance within the Harbor surveyed in 1994 (Harbor Study 1997) was typical of a relatively healthy environment. Algal cover was highest on the Nantucket Sound side between the points of Coatue (Figure VII-10). The highest concentrations of macro-algae were consistent with the circulation patterns associated with the cusps of land present around the Harbor edge. It also appears that the macro-algal accumulations are not related to terrestrial nitrogen inputs, since the "island" side of the Harbor, which dominates the land based loadings, had lower algal accumulations than Coatue. The absence of macroalgal accumulations and drift algae is consistent with the generally low nitrogen levels throughout this System and the relatively low watershed nitrogen input. The infaunal data clearly show that the lower basins and shallower areas (<12') of the main Harbor basins generally support high quality infaunal habitat. The lowermost basin (Town) exhibited a dense, highly diverse and relatively evenly distributed community, with some variation. The shallower margins of both Quaise and Head of the Harbor were only slightly less diverse than areas nearer the tidal inlet, but were clearly of high quality. This is further evidenced by the growth of epibenthic scallops in these areas. Within the main Harbor basins, only the deep "holes" showed reduced numbers of species and individuals and organic enrichment indicators. This indication of moderate to poor habitat in these deep regions is consistent with previous analyses and supported by the observed accumulations of organic detritus in these natural depositional areas. It is unlikely that management of nitrogen loading will be able to create significant improvement within these deep basin regions and it is likely that these areas have been "stressed" by natural processes for a long time. Overall, the MEP system-wide infaunal survey found higher numbers of species and individuals in communities that were generally more diverse and evenly distributed than the other 20 embayments examined to date by the MEP in southeastern Massachusetts. This is consistent with the relatively low tidally averaged nitrogen levels within the system, <0.40 mg N L-1 and generally 0.285-0.361 mg N L-1. 3. Conclusions of the Analysis The threshold nitrogen level for an embayment represents the average watercolumn concentration of nitrogen that will support the habitat quality being sought. The watercolumn nitrogen level is ultimately controlled by the integration of the watershed nitrogen load, the nitrogen concentration in the inflowing tidal waters (boundary condition) and dilution and flushing via tidal flows. The water column nitrogen concentration is modified by the extent of sediment regeneration and by direct atmospheric deposition. Executive Summary 8 Threshold nitrogen levels for this embayment system were developed to restore or maintain SA waters or high habitat quality. In this system, high habitat quality was defined as supportive of eelgrass and supportive of diverse benthic animal communities. Dissolved oxygen and chlorophyll a were also considered in the assessment. Watershed nitrogen loads (Tables ES-1 and ES-2) for the Town of Nantucket, Nantucket Harbor embayment system was comprised primarily of runoff from impervious surfaces, fertilizers and wastewater nitrogen. Land-use and wastewater analysis found that generally about 28% - 53% of the controllable watershed nitrogen load to the embayment was from wastewater. A major finding of the MEP clearly indicates that a single total nitrogen threshold can not be applied to Massachusetts’ estuaries, based upon the results of the Great, Green and Bournes Pond Systems, Popponesset Bay System, the Hamblin / Jehu Pond / Quashnet River analysis in eastern Waquoit Bay, the analysis of the adjacent Rushy Marsh system and the Pleasant Bay and Nantucket Sound embayments associated with the Town of Chatham. This is almost certainly going to be true for the other embayments within the MEP area, as well. The threshold nitrogen levels for the Nantucket Harbor embayment system in Nantucket were determined as follows: Nantucket Harbor Threshold Nitrogen Concentrations • Following the MEP protocol, the restoration target for the Nantucket Harbor system should reflect both recent pre-degradation habitat quality and be reasonably achievable. Determination of the critical nitrogen threshold for maintaining high quality habitat within the Nantucket Harbor Estuarine System is based primarily upon the nutrient and oxygen levels, temporal trends in eelgrass distribution and current benthic community indicators. The Nantucket Harbor System is presently supportive of infaunal habitat throughout its main basins, but is clearly impaired by nitrogen enrichment within the Head of the Harbor basin and in the eastern basin of Polpis Harbor, based upon eelgrass losses. Given the documented importance of eelgrass habitat to these basins and the demonstrable loss of eelgrass that were supported, eelgrass restoration in these basins was set as the primary nitrogen management goal for the overall System. Due to the semi-isolated nature of Polpis Harbor from Nantucket Harbor, it is necessary to establish 2 sentinel stations for eelgrass, one in the Head of the Harbor and one in the east basin of Polpis Harbor (e.g. where eelgrass had been observed in 1951-1989). • It is important to note that the nitrogen levels throughout the Nantucket Harbor System remain relatively low, consistent with the oxygen conditions, lack of macroalgae and chlorophyll a levels. However, the water depth of the Harbor and possibly vertical and horizontal mixing rates appear to have resulted in a decline in eelgrass bed coverage from the deeper areas and more enclosed basin areas. While eelgrass was only recently lost from the east basin of Polpis Harbor, it is presently absent at a tidally average total nitrogen (TN) level of 0.361 mg N L-1. Loss at this nitrogen level is consistent with observed losses in West Falmouth Harbor above 0.350 mg N L-1, however, given the shallower depth of Polpis Harbor, it is likely that it is just slightly above its threshold level at present. Similarly, tidally averaged levels in the lower reach of Head of the Harbor (0.340-0.353) and mid and upper reach (0.390 mg N L-1) also suggest that the recent bed losses are from a recent exceedance of the supportive nitrogen threshold. Given all of the factors discussed above and the similarity of Head of Executive Summary 9 the Harbor to conditions in West Falmouth and Phinneys Harbors and its present nitrogen levels, a nitrogen threshold of 0.350 mg N L-1 was determined to be supportive of eelgrass habitat in this system. This threshold should also support eelgrass in the shallower regions as well. As the east basin of Polpis Harbor has only recently lost its eelgrass and is presently 0.361 mg N L-1, but has shallower waters than Head of the Harbor, only a slight reduction over present levels appears to be needed to support eelgrass habitat. Clearly the threshold must be lower than the present 0.361 mg N L-1 and higher than that for Head of the Harbor (0.350 mg N L-1). Therefore, a threshold of 0.355 mg N L-1 was set for the sentinel station in Polpis Harbor. It should be noted that the Polpis Harbor threshold is well constrained by the available data, but is at the limits of the sensitivity of the MEP approach. It is important to note that the analysis of future nitrogen loading to the Nantucket Harbor estuarine system focuses upon additional shifts in land-use from forest/grasslands to residential and commercial development. However, the MEP analysis indicates that increases in nitrogen loading can occur under present land-uses, due to shifts in occupancy, shifts from seasonal to year-round usage and increasing use of fertilizers. Therefore, watershed-estuarine nitrogen management must include management approaches to prevent increased nitrogen loading from both shifts in land-uses (new sources) and from loading increases of current land-uses. The overarching conclusion of the MEP analysis of the Nantucket Harbor estuarine system is that protection/restoration will necessitate a reduction in the present (2003) nitrogen inputs and management options to negate additional future nitrogen inputs. Executive Summary 10 Table ES-1. Existing total and sub-embayment nitrogen loads to the estuarine waters of the Nantucket Harbor system, observed nitrogen concentrations, and sentinel system threshold nitrogen concentrations. Loads to estuarine waters of the Nantucket Harbor system include both upper watershed regions contributing to the major surface water inputs. Sub-embayments Natural Background Watershed Load 1 (kg/day) Present Land Use Load 2 (kg/day) Present Septic System Load (kg/day) Present WWTF Load 3 (kg/day) Present Watershed Load 4 (kg/day) Direct Atmospheric Deposition 5 (kg/day) Present Net Benthic Flux (kg/day) Present Total Load 6 (kg/day) Observed TN Conc. 7 (mg/L) Threshold TN Conc. 8 (mg/L) NANTUCKET HARBOR SYSTEM Head of the Harbor 0.526 1.152 0.705 0.000 1.858 22.239 -17.211 6.886 0.34-0.41 -- Polpis Harbor 1.836 3.094 0.435 0.000 3.529 2.190 27.441 33.160 0.36-0.39 -- Quaise Basin 0.896 1.731 0.392 0.000 2.123 20.126 43.896 66.145 0.34 -- Town Basin 1.321 10.708 5.194 0.000 15.901 13.888 -2.793 26.997 0.30-0.34 -- Nantucket Harbor System Total 4.578 16.685 6.726 0.000 23.411 58.443 51.333 133.187 0.30-0.41 0.355 1 assumes entire watershed is forested (i.e., no anthropogenic sources) 2 composed of non-wastewater loads, e.g. fertilizer and runoff and natural surfaces and atmospheric deposition to lakes 3 existing unattenuated wastewater treatment facility discharges to groundwater 4 composed of combined natural background, fertilizer, runoff, and septic system loadings 5 atmospheric deposition to embayment surface only. 6 composed of natural background, fertilizer, runoff, septic system atmospheric deposition and benthic flux loadings 7 average of data collected between 1988 and 2005, ranges show the upper to lower regions (highest-lowest) of a sub-embayment. 8 Eel grass threshold for sentinel site located at Polpis Harbor. Executive Summary 11 Table ES-2. Present Watershed Loads, Thresholds Loads, and the percent reductions necessary to achieve the Thresholds Loads for the Nantucket Harbor system. Two threshold scenarios are presented for the Harbor: Scenario A (N1) with 100% removal of septic load from the Town watershed together with 80% removal of anthropogenic watershed loads (septic, fertilizer and non-pervious surfaces) from the remaining three Harbor watersheds; and Scenario B (N2) with the removal of 100% of septic loads from all four of the Harbor Watersheds. Sub-embayments Present Watershed Load 1 (kg/day) Target Threshold Watershed Load 2 (kg/day) Direct Atmospheric Deposition (kg/day) Benthic Flux Net 3 (kg/day) TMDL 4 (kg/day) Percent watershed reductions needed to achieve threshold load levels NANTUCKET HARBOR SYSTEM Head of the Harbor 1.858 N1: 0.792 N2: 1.153 22.239 N1: -16.795 N2: -17.182 N1: 6.235 N2: 6.210 N1: -57.4% N2: -37.9% Polpis Harbor 3.529 N1: 2.175 N2: 3.093 2.190 N1: 26.450 N2: 26.655 N1: 30.816 N2: 31.939 N1: -38.4% N2: -12.3% Quaise Basin 2.123 N1: 1.140 N2: 1.732 20.126 N1: 43.010 N2: 42.885 N1: 64.276 N2: 64.743 N1: -46.3% N2: -18.5% Town Basin 15.901 N1: 10.707 N2: 10.707 13.888 N1: -2.892 N2: -2.892 N1: 21.702 N2: 21.702 N1: -32.7% N2: -32.7% Nantucket Harbor System Total 23.411 N1: 14.814 N2: 16.685 58.443 N1: 49.772 N2: 49.466 N1: 123.029 N2: 124.594 N1: -36.7% N2: -28.7% (1) Composed of combined natural background, fertilizer, runoff, and septic system loadings. (2) Target threshold watershed load is the load from the watershed needed to meet the embayment threshold concentration identified in Table ES-1. (3) Projected future flux (present rates reduced approximately proportional to watershed load reductions). (4) Sum of target threshold watershed load, atmospheric deposition load, and benthic flux load. Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Threshold for the Madaket Harbor and Long Pond Estuarine System, Town of Nantucket, MA FINAL REPORT – November 2010 Massachusetts Department of Environmental Protection University of Massachusetts Dartmouth School of Marine Science and Technology Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Threshold for the Madaket Harbor and Long Pond System, Towns of Nantucket, MA FINAL REPORT – NOVEMBER 2010 Contributors: US Geological Survey Don Walters and John Masterson Applied Coastal Research and Engineering, Inc. Elizabeth Hunt and Trey Ruthven Massachusetts Department of Environmental Protection Charles Costello and Brian Dudley (DEP project manager) SMAST Coastal Systems Program Jennifer Benson, Michael Bartlett, Sara Sampieri and Elizabeth White Cape Cod Commission Tom Cambareri Brian Howes Roland Samimy David Schlezinger Ed Eichner John Ramsey Robert Acker Phil “Jay” Detjens Executive Summary 1 Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Madaket Harbor and Long Pond Nantucket, Massachusetts Executive Summary 1. Background This report presents the results generated from the implementation of the Massachusetts Estuaries Project’s Linked Watershed-Embayment Approach to the Madaket Harbor and Long Pond embayment system, a complex coastal embayment of the Island of Nantucket within the Town of Nantucket, Massachusetts. Analyses of the Madaket Harbor / Long Pond embayment system was performed to assist the Town with up-coming nitrogen management decisions associated with the Towns’ current and future wastewater planning efforts, as well as wetland restoration, anadromous fish runs, shell fishery, open-space, and harbor maintenance programs. As part of the MEP approach, habitat assessment was conducted on the embayment based upon available water quality monitoring data, historical changes in eelgrass distribution, time-series water column oxygen measurements, and benthic community structure. Nitrogen loading thresholds for use as goals for watershed nitrogen management are the major product of the MEP effort. In this way, the MEP offers a science-based management approach to support the Town of Nantucket resource planning and decision-making process. The primary products of this effort are: (1) a current quantitative assessment of the nutrient related health of the Madaket Harbor / Long Pond embayment, (2) identification of all nitrogen sources (and their respective N loads) to embayment waters, (3) nitrogen threshold levels for maintaining Massachusetts Water Quality Standards within embayment waters, (4) analysis of watershed nitrogen loading reduction to achieve the N threshold concentrations in embayment waters, and (5) a functional calibrated and validated Linked Watershed-Embayment modeling tool that can be readily used for evaluation of nitrogen management alternatives (to be developed by the Town) for the protection of Madaket Harbor and restoration of Hither Creek and Long Pond. Wastewater Planning: As increasing numbers of people occupy coastal watersheds, the associated coastal waters receive increasing pollutant loads. Coastal embayments throughout the Commonwealth of Massachusetts (and along the U.S. eastern seaboard) are becoming nutrient enriched. The elevated nutrients levels are primarily related to the land use impacts associated with the increasing population within the coastal zone over the past half-century. Massachusetts Department of Environmental Protection Executive Summary 2 The regional effects of both nutrient loading and bacterial contamination span the spectrum from environmental to socio-economic impacts and have direct consequences to the culture, economy, and tax base of Massachusetts’s coastal communities. The primary nutrient causing the increasing impairment of our coastal embayments is nitrogen, with its primary sources being wastewater disposal, and nonpoint source runoff that carries nitrogen (e.g. fertilizers) from a range of other sources. Nitrogen related water quality decline represents one of the most serious threats to the ecological health of the nearshore coastal waters. Coastal embayments, because of their shallow nature and large shoreline area, are generally the first coastal systems to show the effect of nutrient pollution from terrestrial sources. In particular, the Madaket Harbor / Long Pond embayment system within the Town of Nantucket is at risk of eutrophication (over enrichment) from enhanced nitrogen loads entering through groundwater from the increasingly developed watershed to this coastal system. Eutrophication is a process that occurs naturally and gradually over a period of tens or hundreds of years. However, human-related (anthropogenic) sources of nitrogen may be introduced into ecosystems at an accelerated rate that cannot be easily absorbed, resulting in a phenomenon known as cultural eutrophication. In both marine and freshwater systems, cultural eutrophication results in degraded water quality, adverse impacts to ecosystems, and limits on the use of water resources. The relatively pristine nature of Nantucket's nearshore and Harbor waters has historically been a valuable asset to the island. However, concern over the potential degradation of Harbor water quality began to arise, which resulted in monitoring, scientific investigations and management planning which continues to this day. Madaket Harbor is one of the largest enclosed bays in southeastern Massachusetts and one of the few with a relatively high water quality capable of supporting significant high quality ecological habitats, such as eelgrass beds. Ironically, it is the pristine nature of this system which may indirectly threaten its ecological health as the coastal waters throughout Southeastern New England become increasingly degraded and the pressure for access and development of remaining high quality environments increases. The Town of Nantucket and work groups have long ago recognized that a rigorous scientific approach yielding site-specific nitrogen loading targets was required for decision- making, alternatives analysis and ultimately, habitat protection. The completion of this multi- step process has taken place under the programmatic umbrella of the Massachusetts Estuaries Project, which is a partnership effort between all MEP collaborators and the Town. The modeling tools developed as part of this program provide the quantitative information necessary for the Towns’ nutrient management groups to predict the impacts on water quality from a variety of proposed management scenarios. Nitrogen Loading Thresholds and Watershed Nitrogen Management: Realizing the need for scientifically defensible management tools has resulted in a focus on determining the aquatic system’s assimilative capacity for nitrogen. The highest-level approach is to directly link the watershed nitrogen inputs with embayment hydrodynamics to produce water quality results that can be validated by water quality monitoring programs. This approach when linked to state-of- the-art habitat assessments yields accurate determination of the “allowable N concentration increase” or “threshold nitrogen concentration”. These determined nitrogen concentrations are then directly relatable to the watershed nitrogen loading, which also accounts for the spatial distribution of the nitrogen sources, not just the total load. As such, changes in nitrogen load from differing parts of the embayment watershed can be evaluated relative to the degree to which those load changes drive embayment water column nitrogen concentrations toward the “threshold” for the embayment system. To increase certainty, the “Linked” Model is independently calibrated and validated for each embayment. Executive Summary 3 Massachusetts Estuaries Project Approach: The Massachusetts Department of Environmental Protection (DEP), the University of Massachusetts – Dartmouth School of Marine Science and Technology (SMAST), and others including the Cape Cod Commission (CCC) have undertaken the task of providing a quantitative tool to communities throughout southeastern Massachusetts (the Linked Watershed-Embayment Management Model) for nutrient management in their coastal embayment systems. Ultimately, use of the Linked Watershed-Embayment Management Model tool by municipalities in the region results in effective screening of nitrogen reduction approaches and eventual restoration and protection of valuable coastal resources. The MEP provides technical guidance in support of policies on nitrogen loading to embayments, wastewater management decisions, and establishment of nitrogen Total Maximum Daily Loads (TMDLs). A TMDL represents the greatest amount of a pollutant that a waterbody can accept and still meet water quality standards for protecting public health and maintaining the designated beneficial uses of those waters for drinking, swimming, recreation and fishing. The MEP modeling approach assesses available options for meeting selected nitrogen goals that are protective of embayment health and achieve water quality standards. The core of the Massachusetts Estuaries Project analytical method is the Linked Watershed-Embayment Management Modeling Approach, which links watershed inputs with embayment circulation and nitrogen characteristics. The Linked Model builds on well-accepted basic watershed nitrogen loading approaches such as those used in the Buzzards Bay Project, the CCC models, and other relevant models. However, the Linked Model differs from other nitrogen management models in that it:  requires site-specific measurements within each watershed and embayment;  uses realistic “best-estimates” of nitrogen loads from each land-use (as opposed to loads with built-in “safety factors” like Title 5 design loads);  spatially distributes the watershed nitrogen loading to the embayment;  accounts for nitrogen attenuation during transport to the embayment;  includes a 2D or 3D embayment circulation model depending on embayment structure;  accounts for basin structure, tidal variations, and dispersion within the embayment;  includes nitrogen regenerated within the embayment;  is validated by both independent hydrodynamic, nitrogen concentration, and ecological data;  is calibrated and validated with field data prior to generation of “what if” scenarios. The Linked Model Approach’s greatest assets are its ability to be clearly calibrated and validated, and its utility as a management tool for testing “what if” scenarios for evaluating watershed nitrogen management options. For a comprehensive description of the Linked Model, please refer to the Full Report: Nitrogen Modeling to Support Watershed Management: Comparison of Approaches and Sensitivity Analysis, available for download at http://www.mass.gov/dep/water/resources/coastalr.htm. A more basic discussion of the Linked Model is also provided in Appendix F of the Massachusetts Estuaries Project Embayment Restoration Guidance for Implementation Strategies, available for download at http://www.mass.gov/dep/water/resources/coastalr.htm. The Linked Model suggests which management solutions will adequately protect or restore embayment water quality by enabling Executive Summary 4 towns to test specific management scenarios and weigh the resulting water quality impact against the cost of that approach. In addition to the management scenarios modeled for this report, the Linked Model can be used to evaluate additional management scenarios and may be updated to reflect future changes in land-use within an embayment watershed or changing embayment characteristics. In addition, since the Model uses a holistic approach (the entire watershed, embayment and tidal source waters), it can be used to evaluate all projects as they relate directly or indirectly to water quality conditions within its geographic boundaries. Unlike many approaches, the Linked Model accounts for nutrient sources, attenuation, and recycling and variations in tidal hydrodynamics and accommodates the spatial distribution of these processes. For an overview of several management scenarios that may be employed to restore embayment water quality, see Massachusetts Estuaries Project Embayment Restoration Guidance for Implementation Strategies, available for download at http://www.mass.gov/dep/water/resources/coastalr.htm. Application of MEP Approach: The Linked Model was applied to the Madaket Harbor / Long Pond embayment system by using site-specific data collected by the MEP and water quality data from the Water Quality Monitoring Program conducted by the Nantucket Marine Department, with technical guidance from the Coastal Systems Program at SMAST (see Section II). Evaluation of upland nitrogen loading was conducted by the MEP. Estuaries Project staff obtained digital parcel and tax assessors data from the Town of Nantucket Geographic Information Systems Department, watershed specific water use data from the Wannacomet Water Company (WWC) and watershed boundaries adopted by the town as the Harbor Watershed Protection District (http://www.nantucket-ma.gov). During the development of the Nantucket Water Resources Management Plan, an island-wide groundwater mapping project, using many of the USGS wells on the Island, was completed to characterize the water table configuration of Nantucket (Horsley, Whittan, Hegeman, 1990). Estuary watershed delineations completed in areas with relatively transmissive sand and gravel deposits, like most of Cape Cod and the Islands, have shown that watershed boundaries are usually better defined by elevation of the groundwater and its direction of flow, rather than by land surface topography (Cambareri and Eichner 1998, Millham and Howes 1994a,b). This approach was used by Horsley, Whittan and Hegeman, Inc. (HWH) to complete a watershed delineation for Madaket Harbor (Section III); this watershed delineation was been largely confirmed by subsequent water table characterizations (e.g., Lurbano, 2001, Gardner and Vogel, 2005). MEP staff compared the HWH Harbor watershed to a 2004 aerial base map. This comparison found some slight discrepancies likely based on a better characterization of the shoreline; changes were made based on best professional judgment and watershed/water table characterization experience in similar geologic settings. The watershed to Madaket Harbor has been adopted in the town zoning bylaws as the Madaket Harbor Watershed Protection District. (http://www.nantucket-ma.gov/Pages/NantucketMA_IT/gismapsfolder/madaketharborwpd.pdf). The land-use data obtained from the Town was used to determine watershed nitrogen loads within the Madaket Harbor embayment system and each of the systems sub-embayments as appropriate (current and build-out loads are summarized in Section IV). Water quality within a sub-embayment is the integration of nitrogen loads with the site-specific estuarine circulation. Therefore, water quality modeling of this tidally influenced estuary included a thorough evaluation of the hydrodynamics of the estuarine system. Estuarine hydrodynamics control a variety of coastal processes including tidal flushing, pollutant dispersion, tidal currents, sedimentation, erosion, and water levels. Once the hydrodynamics of the system was quantified, transport of nitrogen was evaluated from tidal current information developed by the numerical models. Executive Summary 5 A two-dimensional depth-averaged hydrodynamic model based upon the tidal currents and water elevations was employed for the Madaket Harbor / Long Pond embayment system. Once the hydrodynamic properties of the estuarine system were computed, two-dimensional water quality model simulations were used to predict the dispersion of the nitrogen at current loading rates. Using standard dispersion relationships for estuarine systems of this type, the water quality model and the hydrodynamic model was then integrated in order to generate estimates regarding the spread of total nitrogen from the site-specific hydrodynamic properties. The distributions of nitrogen loads from watershed sources were determined from land-use analysis. Boundary nutrient concentrations in Nantucket Sound source waters were taken from water quality monitoring data. Measurements of current salinity distributions throughout the estuarine waters of the Madaket Harbor / Long Pond embayment system was used to calibrate the water quality model, with validation using measured nitrogen concentrations (under existing loading conditions). The underlying hydrodynamic model was calibrated and validated independently using water elevations measured in time series throughout the embayments. MEP Nitrogen Thresholds Analysis: The threshold nitrogen level for an embayment represents the average water column concentration of nitrogen that will support the habitat quality being sought. The water column nitrogen level is ultimately controlled by the watershed nitrogen load and the nitrogen concentration in the inflowing tidal waters (boundary condition). The water column nitrogen concentration is modified by the extent of sediment regeneration. Threshold nitrogen levels for the embayment systems in this study were developed to restore or maintain SA waters or high habitat quality. High habitat quality was defined as supportive of eelgrass and infaunal communities. Dissolved oxygen and chlorophyll a were also considered in the assessment. The nitrogen thresholds developed in Section VIII-2 were used to determine the amount of total nitrogen mass loading reduction required for restoration of eelgrass and infaunal habitats in the Madaket Harbor / Long Pond system. Tidally averaged total nitrogen thresholds derived in Section VIII.1 were used to adjust the calibrated constituent transport model developed in Section VI. Watershed nitrogen loads were sequentially lowered, using reductions in septic effluent discharges only, until the nitrogen levels reached the threshold level at the sentinel station chosen for the Madaket Harbor system. It is important to note that load reductions can be produced by reduction of any or all sources or by increasing the natural attenuation of nitrogen within the freshwater systems to the embayment. The load reductions presented below represent only one of a suite of potential reduction approaches that need to be evaluated by the community. The presentation is to establish the general degree and spatial pattern of reduction that will be required for protection/restoration of this nitrogen threatened embayment. The Massachusetts Estuaries Project’s thresholds analysis, as presented in this technical report, provides the site-specific nitrogen reduction guidelines for nitrogen management of the Madaket Harbor / Long Pond embayment system in the Town of Nantucket. Future water quality modeling scenarios should be run which incorporate the spectrum of strategies that result in nitrogen loading reduction to the embayment. The MEP analysis has initially focused upon nitrogen loads from on-site septic systems as a test of the potential for achieving the level of total nitrogen reduction for restoration of the embayment system. The concept was that since septic system nitrogen loads generally represent 58% of the controllable watershed load to the Madaket Harbor embayment system and are more manageable than other of the nitrogen sources, the ability to achieve needed reductions through this source is a good gauge of the feasibility for protection/restoration of the system. Additionally, an alternative scenario was completed which focused on the elimination of nitrogen loads to the Long Pond portion of the embayment system as that source represents 24% of the controllable watershed load to the Executive Summary 6 Madaket Harbor embayment system and is also more manageable than other of the nitrogen sources. 2. Problem Assessment (Current Conditions) A habitat assessment was conducted throughout the Madaket Harbor / Long Pond system based upon available water quality monitoring data, historical changes in eelgrass distribution, time-series water column oxygen measurements, and benthic community structure. The Madaket Harbor-Long Pond Embayment System is a complex estuary with full tidal marine basins (Madaket Harbor, Hither Creek) connected via Madaket Ditch to tidally restricted brackish water basins (Long Pond, North Head Long Pond) that have significant wetland influence. Each of type of functional component (salt marsh basin, embayment, tidal river, deep basin (sometimes drown kettles), shallow basin, etc.) has a different natural sensitivity to nitrogen enrichment and organic matter loading. Evaluation of eelgrass and infaunal habitat quality must consider the natural structure of the specific type of basin and the ability to support eelgrass beds and the types of infaunal communities that they support. At present, some of the component basins within the Madaket Harbor-Long Pond Estuary are showing nitrogen enrichment and impairment of both eelgrass and infaunal habitats (Section VII), indicating that nitrogen management of this system will be for restoration rather than for protection or maintenance of an unimpaired system. Overall, the large open water semi-enclosed main basin of Madaket Harbor is presently supporting high quality eelgrass habitat and productive benthic animal communities. Oxygen generally shows little depletion and chlorophyll a levels were consistently low. It is clear that the open nature of this basin and its relatively small watershed have resulted in only a low level of nitrogen enrichment and high quality habitat. In contrast, the enclosed basin of Hither Creek is presently nitrogen enriched, with high chlorophyll levels and periodic hypoxia (low oxygen). Habitat impairment is clear from the loss of previously existing eelgrass beds and the near absence of benthic animals in the upper reaches. The brackish basins of Long Pond and North Head of Long Pond are also nitrogen enriched beyond their assimilative capacity, but given the natural nutrient and organic matter enrichment of wetland influenced tidal basins their level of impairment is only moderate. There is no evidence that eelgrass habitat has existed previously in these basins, so the present absence does not indicate impairment of this habitat. The level of oxygen depletion and the magnitude of daily oxygen excursion and chlorophyll a levels indicate only slightly nutrient enriched conditions within Madaket Harbor and moderate to significant impairment of the enclosed component basins. However, the degree of enrichment and subsequent effect on habitat quality varied widely between these impaired sub- basins. Madaket Harbor, which functions as a open marine basin generally has only moderate declines in oxygen, moderate amounts of phytoplankton biomass (chlorophyll a), and a low level of nitrogen enrichment (tidally averaged TN <0.33 mg L-1), all factors consistent with its high quality eelgrass habitat. In contrast, Hither Creek's oxygen and chlorophyll a levels indicate a nitrogen and organic matter enriched basin with oxygen frequently declining below 4 mg L-1 and 3 mg L-1. Chlorophyll a levels were also significantly elevated. These elevated levels of phytoplankton are consistent with the observed periodic bottom water hypoxia and organic rich soft sediments of the basin. The periodic hypoxia, elevated chlorophyll levels and sediment characteristics are consistent with a nitrogen enriched basin with significantly impaired eelgrass Executive Summary 7 habitat. The oxygen and chlorophyll a data further support the conclusion that Hither Creek habitats are likely presently impaired by nitrogen enrichment. Long Pond is a tidally restricted brackish pond dominated by fringing wetlands. Oxygen depletion is large and frequent, generally following the diurnal light/dark cycle. Oxygen frequently declined to <2 mg L-1, with a large daily excursion frequently rising to 2-3 times air equilibration. Although natural wetland channels periodically are hypoxic/anoxic at night, the large daily oxygen excursions are atypical and indicate impairment. Consistent with the oxygen levels, chlorophyll a levels were also very high. The oxygen and chlorophyll a data indicate that while the middle portion of Long Pond is a wetland dominated basin and therefore naturally nutrient and organic matter enriched, the large phytoplankton blooms coupled with the large oxygen excursions suggest that it is currently beyond its nutrient assimilative capacity. The southern tidal reach of Long Pond is less nutrient enriched and shows a lower degree of habitat impairment. While Long Pond, overall, has significant wetland influence and therefore is naturally enriched in nutrients and organic matter the chlorophyll a and to a lesser extent oxygen records indicate that this lower basin is also beyond its nutrient assimilative capacity. Overall, the oxygen and chlorophyll a levels within the Madaket Harbor - Long Pond System indicate little to no impairment of the outer harbor consistent with its low level of nitrogen enrichment. In contrast, Hither Creek which receives high quality waters on the flooding tide from Madaket Harbor, but nutrient and organic matter enrichment from its watershed inputs and from the upper estuarine reaches via Madaket Ditch, has oxygen declines and chlorophyll levels consistent with its tidally averaged TN of 0.51 mg L-1 (Section VI), indicating nitrogen related habitat impairment. Long Pond and North Head of Long Pond are brackish wetland influenced systems that are naturally enriched with nutrients and organic matter. The North Head of Long Pond supported generally high oxygen conditions and moderate chlorophyll a levels at a high tidally averaged TN (0.89 mg L-1). Based upon the function type of this basin, the oxygen and chlorophyll a levels are indicative of high quality to possibly slightly impaired habitat. In contrast, the wetland dominated Long Pond basin is presently showing wide oxygen excursions, frequent hypoxia/anoxia and very high chlorophyll levels indicating that even this naturally enriched system is receiving external nitrogen loading that is resulting in habitat impairments. The survey of infauna communities throughout the Madaket Harbor-Long Pond Estuary indicated a system presently supporting impaired benthic infaunal habitat in its enclosed component sub-basins (Hither Creek, Long Pond, North Head of Long Pond). A wide range of benthic animal habitat quality exists within the Madaket Harbor-Long Pond Embayment System. The highest quality infauna habitat was found throughout the main basin of Madaket Harbor that also presently supports extensive eelgrass beds and sustains high oxygen levels and low chlorophyll levels, consistent with its low level of nitrogen enrichment. In contrast, Hither Creek has low numbers of individuals, species and diversity and is dominated by organic enrichment tolerant species (Capitellids). The upper reach of Hither Creek (between water quality monitoring sites MAD 9 & 10) did not support any significant infaunal habitat. The observed impaired infauna habitat is consistent with the observed oxygen and chlorophyll levels in this basin. Long Pond and North Head of Long Pond are brackish water basins with significant wetland influence. As such, these basins are naturally nutrient and organic matter enriched, and assessment of infaunal habitat accounted for their functional types. Overall, these brackish basins presently support productive benthic animal communities. Long Pond supports high numbers of individuals, but low species numbers, diversity and Evenness. The low numbers of total species and overall diversity indicate an impaired habitat consistent with Executive Summary 8 the observed hypoxic conditions and elevated chlorophyll levels. The North Head of Long Pond is similar to Long Pond with lower numbers of individuals, but the community is dominated by amphipods rather than oligochaeta worms, indicative of a productive organic rich habitat and consistent with the observed oxygen levels in this basin. At present, eelgrass coverage is extensive and stable throughout the main portion of Madaket Harbor. The existing beds have increased significantly relative to the estimate from 1951. The temporal pattern of eelgrass coverage in Hither Creek clearly indicates that the eelgrass habitat within this basin is presently significantly impaired. In 1951, eelgrass beds covered much of the main basin of the Creek. However, by 1995 the beds had been significantly reduced and limited to the margins of the basin and eelgrass was not found in the 2001 and 2006 MassDEP surveys or the MEP 2003 observations. The recent loss of the 1995 beds coupled with measured periodic hypoxia and high chlorophyll a levels supports the contention that nitrogen enrichment caused the decline in eelgrass habitat. Deepening the basin does impact the ability to restore eelgrass in this basin to 1951 coverage, since the basin is now deeper and depositional. In its present basin configuration, restoration of the eelgrass habitat in Hither Creek, should focus on restoration of the fringing beds in the shallower margins of the basin to the inland extent of the 1951 coverage (water quality station, M11). In contrast to Madaket Harbor and Hither Creek, the Long Pond basins do not appear to have eelgrass habitat, as there is not present or historical evidence of eelgrass within these basins. Management of nitrogen levels through reduction in watershed nitrogen inputs or increased tidal flushing, as appropriate, is required for restoration of eelgrass and infaunal habitats within the Madaket Harbor-Long Pond Embayment System. 3. Conclusions of the Analysis The threshold nitrogen level for an embayment represents the average watercolumn concentration of nitrogen that will support the habitat quality being sought. The watercolumn nitrogen level is ultimately controlled by the integration of the watershed nitrogen load, the nitrogen concentration in the inflowing tidal waters (boundary condition) and dilution and flushing via tidal flows. The water column nitrogen concentration is modified by the extent of sediment regeneration and by direct atmospheric deposition. Threshold nitrogen levels for this embayment system were developed to restore or maintain SA waters or high habitat quality. In this system, high habitat quality was defined as supportive of eelgrass and supportive of diverse benthic animal communities. Dissolved oxygen and chlorophyll a were also considered in the assessment. Watershed nitrogen loads (Tables ES-1 and ES-2) for the Town of Nantucket, Madaket Harbor / Long Pond embayment system was comprised primarily of runoff from impervious surfaces, fertilizers and wastewater nitrogen. Land-use and wastewater analysis found that generally about 58% of the controllable watershed nitrogen load to the embayment was from wastewater. A major finding of the MEP clearly indicates that a single total nitrogen threshold cannot be applied to Massachusetts’ estuaries, based upon the results of the Great, Green and Bournes Pond Systems, Popponesset Bay System, the Hamblin / Jehu Pond / Quashnet River analysis in eastern Waquoit Bay and the analysis of the adjacent Nantucket Harbor and Sesechacha Pond systems on the Island of Nantucket. This is almost certainly going to be true for the other embayments within the MEP area, as well as Madaket Harbor and Long Pond. Executive Summary 9 The threshold nitrogen levels for the Madaket Harbor / Long Pond embayment system in Nantucket were determined as follows: Madaket Harbor / Long Pond Threshold Nitrogen Concentrations:  Following the MEP protocol, the restoration target for the Madaket Harbor / Long Pond system should reflect both recent pre-degradation habitat quality and be reasonably achievable. Determination of the critical nitrogen threshold for maintaining high quality habitat within the Madaket Harbor Estuarine System is based primarily upon the nutrient and oxygen levels, temporal trends in eelgrass distribution and current benthic community indicators. Given the information on a variety of key habitat and basin characteristics, it is possible to develop a site-specific threshold at a sentinel location within the embayment. The sentinel location is selected such that the restoration of that one site will necessarily bring the other regions of the system to acceptable habitat quality levels, which is a refinement upon more generalized threshold analyses frequently employed. Evaluation of eelgrass and infaunal habitat quality must consider the natural structure of the specific type of basin and the ability to support eelgrass beds and the types of infaunal communities that they support. At present, some of the component basins within the Madaket Harbor-Long Pond Estuary are showing nitrogen enrichment and impairment of both eelgrass and infaunal habitats (Section VII), indicating that nitrogen management of this system will be for restoration rather than for protection or maintenance of an unimpaired system.  Overall, the large open water semi-enclosed main basin of Madaket Harbor is presently supporting high quality eelgrass habitat and productive benthic animal communities. Oxygen generally shows little depletion and chlorophyll a levels were consistently low, with only very sparse macroalgal abundance.  The enclosed basin of Hither Creek is presently nitrogen enriched with a tidally averaged TN of 0.51 mg N L-1 compared to 0.33 mg N L-1 in Madaket Harbor. The result is high chlorophyll levels and periodic hypoxia (low oxygen), complete loss of eelgrass habitat and regions of dense accumulations of drift macroalgae. In addition, the benthic animal habitat is impaired and nearly absent in much of the northern tidal basin. While nitrogen management needs to target eelgrass restoration in this basin, it will also restore benthic animal habitat, as benthic communities are generally more tolerant of nitrogen enrichment effects than is eelgrass.  The brackish basins of Long Pond and North Head of Long Pond are also nitrogen enriched beyond their assimilative capacity, but given the natural nutrient and organic matter enrichment of wetland influenced tidal basins their level of impairment is only moderate. TN levels are elevated in these basins, 0.85 - 1.05 mg N L-1, typical of wetland basins and tidal creeks. However, some impairment of habitat presently exists, seen primarily in the high chlorophyll levels and periodic blooms and structure of the benthic animal community. There is no evidence that eelgrass habitat has existed previously in these basins, so the present absence does not indicate impairment of this habitat.  The decline in eelgrass within Hither Creek makes restoration of eelgrass the target for TMDL development by MassDEP and the primary focus of threshold development for Executive Summary 10 this system. Additionally, restoration of the basins with impaired benthic animal habitat is also required. However, given the level of impairment in the brackish basins and the goal of restoring eelgrass in Hither Creek, it is certain that nitrogen management to restore eelgrass habitat within Hither Creek the will also result in restoration of the impaired infaunal habitat, as nitrogen enrichment will be significantly reduced to the overall estuary. As such, it appears that the appropriate sentinel station for the Madaket Harbor-Long Pond Embayment System should be located at the northern most extent of the 1951 eelgrass coverage in Hither Creek, which coincides with the baseline Nantucket Water Quality Monitoring Station, M11. To achieve the restoration target of restoring the fringing eelgrass beds in Hither Creek requires lowering the level of nitrogen enrichment. Within Madaket Harbor the basin-wide tidally averaged TN is presently <0.33 mg N L-1, and the basin is supporting high quality eelgrass and benthic infaunal habitat. However, Madaket Harbor eelgrass coverage includes areas in deeper water than that of the location of the fringing eelgrass beds to be restored in Hither Creek (< 1 m) and so a higher level of nitrogen is appropriate for restoration in Hither Creek.  In shallow systems like the restoration area in Hither Creek, eelgrass beds are sustainable at higher TN (higher chlorophyll a) levels than in deeper waters, because of the "thinner" water column that light has to pass through to support eelgrass growth (less water to penetrate). Therefore to restore eelgrass habitat in Hither Creek the nitrogen concentration (tidally averaged TN) at the sentinel location needs to be between 0.48 and 0.43 mg TN L-1. A threshold of 0.45 mg TN L-1 was determined to be appropriate for the Hither Creek sentinel station to restore eelgrass (and infaunal habitat) within this basin.  It should be noted that as the benthic habitats in the brackish components (Long Pond and the North Head of Long Pond) of the overall system are naturally nitrogen enriched, a moderate reduction in nitrogen levels should be sufficient to restore the benthic habitat. In tidal wetlands the nitrogen levels between 1 and 2 mg N L-1 are associated with unimpaired habitat. This is consistent with the only slight impairment of the North Head of Long Pond at TN levels of 0.894 mg L-1 and the moderately impaired benthic habitat in Long Pond at a basin averaged TN (tidally averaged) of 0.939 mg N L-1. Given the observed level of impairment in these brackish basins and the frequent association of high quality benthic habitat in wetland influenced tidal channels at 1 mg N L-1, a threshold of 0.8 mg N L-1 is appropriate as the average basin TN level to be supportive of benthic animal habitat. This is a secondary threshold and one that should be met as nitrogen management options are implemented to meet the nitrogen threshold at the down-gradient sentinel station in Hither Creek. It is important to note that the analysis of future nitrogen loading to the Madaket Harbor / Long Pond estuarine system focuses upon additional shifts in land-use from forest/grasslands to residential and commercial development. However, the MEP analysis indicates that increases in nitrogen loading can occur under present land-uses, due to shifts in occupancy, shifts from seasonal to year-round usage and increasing use of fertilizers. Therefore, watershed-estuarine nitrogen management must include management approaches to prevent increased nitrogen loading from both shifts in land-uses (new sources) and from loading increases of current land-uses. The overarching conclusion of the MEP analysis of the Madaket Harbor / Long Pond estuarine system is that protection/restoration will necessitate a reduction in the present (2009) nitrogen inputs and management options to negate additional future nitrogen inputs. Executive Summary 11 Table ES-1. Existing total and sub-embayment nitrogen loads to the estuarine waters of the Madaket Harbor and Long Pond estuary system, observed nitrogen concentrations, and sentinel system threshold nitrogen concentrations. Sub-embayments Natural Background Watershed Load 1 (kg/day) Present Land Use Load 2 (kg/day) Present Septic System Load (kg/day) Present WWTF Load 3 (kg/day) Present Watershed Load 4 (kg/day) Direct Atmospheric Deposition 5 (kg/day) Present Net Benthic Flux (kg/day) Present Total Load 6 (kg/day) Observed TN Conc. 7 (mg/L) Threshold TN Conc. (mg/L) SYSTEMS Madaket Bay 0.238 0.279 0.384 -- 0.663 8.603 17.952 27.218 0.34-0.42 -- Hither Creek 0.425 1.134 2.907 -- 4.041 0.534 -0.583 3.992 0.58-0.78 -- Madaket Ditch 0.507 0.923 1.510 -- 2.433 - 0.061 2.494 -- -- Long Pond 0.142 2.888 0.342 -- 3.230 0.975 3.065 7.270 0.24-0.40 System Total 1.457 5.392 5.214 -- 10.605 10.805 21.490 42.901 -- 0.458 1 assumes entire watershed is forested (i.e., no anthropogenic sources) 2 composed of non-wastewater loads, e.g. fertilizer and runoff and natural surfaces and atmospheric deposition to lakes 3 existing wastewater treatment facility discharges to groundwater 4 composed of combined natural background, fertilizer, runoff, and septic system loadings 5 atmospheric deposition to embayment surface only 6 composed of natural background, fertilizer, runoff, septic system atmospheric deposition and benthic flux loadings 7 average of 2001 – 2008 data, ranges show the upper to lower regions (highest-lowest) of an sub-embayment. Individual yearly means and standard deviations in Table VI-1. 8 Threshold for sentinel site located in Hither Creek at water quality station M-11 Executive Summary 12 Table ES-2. Present Watershed Loads, Thresholds Loads, and the percent reductions necessary to achieve the Thresholds Loads for the Madaket Harbor and Long Pond estuary system, Town of Madaket, Massachusetts. Sub-embayments Present Watershed Load 1 (kg/day) Target Threshold Watershed Load 2 (kg/day) Direct Atmospheric Deposition (kg/day) Benthic Flux Net 3 (kg/day) TMDL 4 (kg/day) Percent watershed reductions needed to achieve threshold load levels SYSTEMS Madaket Bay 0.663 0.663 8.603 17.952 27.22 0.00% Hither Creek 4.041 1.134 0.534 -0.583 1.09 -71.94% Madaket Ditch 2.433 2.433 - 0.061 2.49 0.00% Long Pond 3.230 1.101 0.975 3.065 5.14 -65.91% North Head Long Pond 0.238 0.238 0.693 0.995 1.93 0.00% System Total 10.605 5.570 10.805 21.49 37.86 -47.48% (1) Composed of combined natural background, fertilizer, runoff, and septic system loadings. (2) Target threshold watershed load is the load from the watershed needed to meet the embayment threshold concentration identified in Table ES-1. (3) Projected future flux (present rates reduced approximately proportional to watershed load reductions). (4) Sum of target threshold watershed load, atmospheric deposition load, and benthic flux load. Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Sesachacha Pond, Town of Nantucket, Massachusetts University of Massachusetts Dartmouth School of Marine Science and Technology Massachusetts Department of Environmental Protection FINAL REPORT – NOVEMBER 2006 Sesachahcha Pond Quidnet Hoicks Hollow Sesachahcha Pond Quidnet Hoicks Hollow Sesachahcha Pond Quidnet Hoicks Hollow © [2006] University of Massachusetts All Rights Reserved Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Sesachacha Pond, Town of Nantucket Nantucket Island, Massachusetts FINAL REPORT – NOVEMBER 2006 Brian Howes Roland Samimy David Schlezinger Sean Kelley John Ramsey Mark Osler Ed Eichner Contributors: US Geological Survey Don Walters and John Masterson Applied Coastal Research and Engineering, Inc. Elizabeth Hunt Massachusetts Department of Environmental Protection Charles Costello and Brian Dudley (DEP manager) SMAST Coastal Systems Program George Hampson and Sara Sampieri Cape Cod Commission Xiaotong Wu © [2006] University of Massachusetts All Rights Reserved ACKNOWLEDGMENTS The Massachusetts Estuaries Project Technical Team would like to acknowledge the contributions of the many individuals who have worked tirelessly for the restoration and protection of the critical coastal resources of the Nantucket Harbor System. Without these stewards and their efforts, this project would not have been possible. First and foremost is the significant time and effort in data collection and discussion spent by members of the Town of Nantucket Water Quality Monitoring Program, particularly Dave Fronzuto and its Coordinator, Keith Conant and former Coordinator, Tracey Curley. These individuals gave of their time to collect nutrient samples from this system over many years and without this information, the present analysis would not have been possible. A special thank you is extended to Richard Ray of the Town of Nantucket Health Department for all the assistance provided over the years thus making this report as specific as possible to the Island. In addition, over the years, the Town of Nantucket Shellfish and Marine Department has worked tirelessly with SMAST Coastal Systems Staff, engineers from Applied Coastal Research and Engineering, and the Cape Cod Commission towards the development of a restoration and management strategy for this system over the past decade. The Marine Department has also provided important support to the present MEP effort. The technical team would also like to specifically acknowledge the efforts of Cormac Collier of the Nantucket Land Council and Andrew Vorce, Director of the Nantucket Planning and Economic Development Commission for facilitating the land use analysis effort within the MEP. A special thanks is given to Linda Holland the prior Director of the Nantucket Land Council who played a key role in promoting scientifically based management of Nantucket's estuarine systems throughout the 1990's. In addition to local contributions, technical, policy and regulatory support has been freely and graciously provided by Dr. Tony Millham of the Lloyd Center for Environmental Studies who provided previously collected data on pond elevations. Tom Cambareri and Margo Fenn of the Cape Cod Commission; MaryJo Feurbach, Art Clark and Nora Conlon of the USEPA; and our MADEP colleagues: Andrew Gottlieb (now at ODC), Arleen O’Donnell, Art Screpetis, Rick Dunn, Steve Halterman, and Russ Issacs. We are also thankful for the long hours in the field and laboratory spent by the technical staff (Paul Henderson, Nat Donkin, George Hampson), interns and students within the Coastal Systems Program at SMAST-UMD. Support for this project was provided by the Town of Nantucket (Shellfish and Marine Department), Barnstable County, MADEP, and the USEPA. CITATION Howes B., S. W. Kelley, M. Osler, J. S. Ramsey, R. Samimy, D. Schlezinger, E. Eichner (2006). Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Sesachacha Pond, Town of Nantucket, Nantucket Island, Massachusetts. Massachusetts Estuaries Project, Massachusetts Department of Environmental Protection. Boston, MA. Massachusetts Estuaries Project i TABLE OF CONTENTS I. INTRODUCTION ......................................................................................................................1 I.1 THE MASSACHUSETTS ESTUARIES PROJECT APPROACH........................................6 I.2 SITE DESCRIPTION...........................................................................................................9 I.3 NUTRIENT LOADING.......................................................................................................12 I.4 WATER QUALITY MODELING.........................................................................................13 I.5 REPORT DESCRIPTION..................................................................................................14 II. PREVIOUS STUDIES RELATED TO NITROGEN MANAGEMENT.....................................15 III. DELINEATION OF WATERSHEDS.....................................................................................24 III.1 BACKGROUND...............................................................................................................24 III.2 SESACHACHA POND CONTRIBUTORY AREAS .........................................................24 IV. WATERSHED NITROGEN LOADING TO EMBAYMENT: LAND USE, STREAM INPUTS, AND SEDIMENT NITROGEN RECYCLING....................................................27 IV.1 WATERSHED LAND USE BASED NITROGEN LOADING ANALYSIS.........................27 IV.1.1 Land Use and Water Use Database Preparation.....................................................28 IV.1.2 Nitrogen Loading Input Factors................................................................................30 IV.1.3 Calculating Nitrogen Loads......................................................................................34 IV.2 ATTENUATION OF NITROGEN IN SURFACE WATER TRANSPORT.........................38 IV.2.1 Background and Purpose.........................................................................................38 IV.3 BENTHIC REGENERATION OF NITROGEN IN BOTTOM SEDIMENTS..................38 IV.3.1 Sediment-Watercolumn Exchange of Nitrogen........................................................38 IV.3.2 Method for determining sediment-watercolumn nitrogen exchange.........................39 IV.3.3 Rates of Summer Nitrogen Regeneration from Sediments......................................42 Sesachacha Pond................................................................................................................44 V. HYDRODYNAMIC MODELING ............................................................................................47 V.1 INTRODUCTION..............................................................................................................47 V.1.1 System Physical Setting............................................................................................47 V.1.2 System Hydrodynamic Setting...................................................................................48 V.2 GEOMORPHIC AND ANTHROPOGENIC EFFECTS TO THE SYSTEM .......................49 V.2.1 Pond Management Practices.....................................................................................49 V.2.2 Shoreline Change Analysis........................................................................................50 V.3 HYDRODYNAMIC FIELD DATA COLLECTION AND ANALYSIS...................................51 V.3.1. Bathymetry................................................................................................................53 V.3.2 Tide Data...................................................................................................................53 V.4 HYDRODYNAMIC MODEL DEVELOPMENT..................................................................53 V.4.1 Modeling flow through a breach................................................................................54 V.4.2 Modeling the breach at Sesachacha Pond.................................................................59 V.4.3 RMA2 model theory...................................................................................................59 V.4.4 RMA2 model development........................................................................................60 V.5. FLUSHING CHARACTERISTICS...................................................................................62 VI. WATER QUALITY MODELING ............................................................................................63 VI.1 DATA SOURCES FOR THE MODEL.............................................................................63 VI.1.1 Hydrodynamics and Tidal Flushing in the Embayments ..........................................63 VI.1.2 Nitrogen Loading to the Embayments......................................................................63 Massachusetts Estuaries Project ii VI.1.3 Measured Nitrogen Concentrations in the Embayments..........................................64 VI.2 MODEL DESCRIPTION AND APPLICATION ................................................................64 VI.2.1 Model Formulation.....................................................................................................65 VI.2.1.1 Dispersion Model...............................................................................................65 VI.2.1.2 Mass Balance Model..............................................................................................66 VI.2.2 Boundary Condition Specification ............................................................................67 VI.2.3 Development of Present Conditions Model.............................................................67 VI.2.4 Total Nitrogen Model Verification.............................................................................70 VI.2.5 Build-Out and No Anthropogenic Load Scenarios....................................................72 VI.2.5.1 Build-Out............................................................................................................72 VI.2.5.2 No Anthropogenic Load.....................................................................................73 VII. ASSESSMENT OF EMBAYMENT NUTRIENT RELATED ECOLOGICAL HEALTH........75 VII.1 OVERVIEW OF BIOLOGICAL HEALTH INDICATORS.................................................75 VII.2 BOTTOM WATER DISSOLVED OXYGEN....................................................................76 VII.3 EELGRASS DISTRIBUTION - TEMPORAL ANALYSIS................................................81 VII.4 BENTHIC INFAUNA ANALYSIS....................................................................................81 VIII. CRITICAL NUTRIENT THRESHOLD DETERMINATION AND DEVELOPMENT OF WATER QUALITY TARGETS........................................................................................84 VIII.1 ASSESSMENT OF NITROGEN RELATED HABITAT QUALITY .................................84 VIII.2 THRESHOLD NITROGEN CONCENTRATIONS.........................................................85 VIII.3 DEVELOPMENT OF TARGET NITROGEN LOADS....................................................86 IX. REFERENCES......................................................................................................................91 Massachusetts Estuaries Project iii LIST OF FIGURES Figure I-1. Location of the Sesachacha Pond system, Island of Nantucket, Town of Nantucket, Massachusetts. Sesachacha Pond is a great salt pond, historically maintained by periodic breaching of the barrier beach to allow exchange with Atlantic Ocean waters....................................................................1 Figure I-2. Study region for the Massachusetts Estuaries Project analysis of the Sesachacha Pond System. Tidal waters enter the Pond from the Atlantic Ocean during periodic openings of the barrier beach. Freshwaters enter from the watershed primarily through direct groundwater discharge and direct precipitation. ................................................................................................2 Figure I-3. Sesachacha Pond bathymetry depicting major basins, Town of Nantucket, Massachusetts (EIR 1989)..................................................................4 Figure I-4. Massachusetts Estuaries Project Critical Nutrient Threshold Analytical Approach.............................................................................................................11 Figure II-1. Town of Nantucket Water Quality Monitoring Program sampling stations for Sesachacha Pond as provided by the Town of Nantucket Marine Department..........................................................................................................23 Figure III-1. Watershed delineations for the Sesachacha estuary system..............................25 Figure IV-1. Land-use in the Sesachacha Pond watershed. The watershed is completely contained within the Town of Nantucket. Land use classifications are based on assessors’ records provided by the town...............29 Figure IV-2. Distribution of land-uses by area within the watershed to Sesachacha Pond....................................................................................................................30 Figure IV-3. Parcels, Parcelized Watersheds, and Developable Parcels in the Sesachacha Pond watershed..............................................................................35 Figure IV-4. Land use-specific unattenuated nitrogen load (by percent) to the Sesachacha Pond System watershed. “Overall Load” is the total nitrogen input within the watershed, while the “Local Control Load” represents only those nitrogen sources that could potentially be under local regulatory control..................................................................................................................37 Figure IV-5. Sesachacha Pond embayment system sediment sampling sites (red symbols) for determination of nitrogen regeneration rates. Numbers are for reference to Table IV-3...................................................................................41 Figure IV-6. Conceptual diagram showing the seasonal variation in sediment N flux, with maximum positive flux (sediment output) occurring in the summer months, and maximum negative flux (sediment up-take) during the winter months.................................................................................................................43 Figure IV-7. Time course of average total nitrogen concentrations in Sesachacha Pond during non-open periods in summers of 2004 (top) and 2005 (bottom). The linear increase in total nitrogen is directly proportional to duration of pond closure......................................................................................46 Figure V-1. Topographic map detail of Sesachacha Pond, Nantucket Island, Massachusetts. ...................................................................................................48 Figure V-2. Salinity of Sesachacha Pond between 1967 and 1988 (from Kelly, 1988)..........49 Figure V-3. Record of pond openings between 1997 and 2004 indicating the relative success of the opening (in days), as well average annual salinity levels (Curley, 2004)......................................................................................................50 Figure V-4. Historical shoreline change rates (1955-2003) in the area of Sesachacha Pond....................................................................................................................52 Massachusetts Estuaries Project iv Figure V-5. Bathymetry survey lines (yellow) followed by the boat in Sesachacha Pond. The final RMA2 grid used for hydrodynamic and water quality modeling is also shown as the white mesh. ........................................................54 Figure V-6. Nantucket Harbor tides used for the water level outside Sesachacha Pond for the hydrodynamic model. Elevations are referenced to MLLW. ..........55 Figure V-7. Area map detail of Edgartown Great Pond, Martha’s Vineyard, Massachusetts. ...................................................................................................56 Figure V-8. Water elevations during the breach event in Edgartown Great Pond..................57 Figure V-9. A comparison of the broad-crested weir model results with the recorded pond elevations during the breach event at Edgartown Great Pond...................58 Figure V-10. Weir model results for a breach event at Sesachacha Pond. The blue line represents the predicted water elevation in the pond. These values were used as the boundary condition for the RMA2 hydrodynamic model of the pond. ...................................................................................................................60 Figure V-11. Interpolated bathymetric contours of the final RMA2 computational mesh of Sesachacha Pond. Depth contours are relative to the MLLW........................61 Figure VI-1. 2005 aerial photo showing monitoring station location in Sesachacha Pond that was used in the water quality analysis................................................65 Figure VI-2. RMA-4 salinity dispersion model output for simulation of the spring 2004 opening of Sesachacha Pond. For this opening event, the inlet allowed tidal exchange with the Atlantic Ocean for 25 days before it closed again..........68 Figure VI-3. Comparison of measured (black circles) and modeled (red triangles) salinities through the summer of 2004, beginning with the spring breaching of an inlet to the Atlantic Ocean. The first two data points bracket the period of time that the inlet was open, and the Pond was tidally flushed. This breach period was simulated using the RMA-4 model of the Pond. Between May and November, the breach was closed, which prevented any tidal exchange. This period through the summer was simulated using the mass balance model. Results of the sensitivity analysis are also presented, showing model output using recharge rate determined by the Cape Cod Commission (CCC) and zero recharge. ...............69 Figure VI-4. Model salinity target values are plotted against measured concentrations, together with the unity line, for the simulation period from May through November 2004. RMS error for this model verification run is 0.89 ppt and the R2 correlation coefficient is 0.75....................................................................69 Figure VI-5. RMA-4 total nitrogen dispersion model output for simulation of the spring 2004 opening of Sesachacha Pond. For this opening event, the inlet allowed tidal exchange with the Atlantic Ocean for 25 days before it closed again. .......................................................................................................70 Figure VI-6. Comparison of measured (black circles) and modeled (red triangles) total nitrogen concentrations through the summer of 2004, beginning with the spring breaching of an inlet to the Atlantic Ocean. The first two data points bracket the period of time that the inlet was open, and the Pond was tidally flushed. Between May and November, the breach was closed, which prevented any tidal exchange. Results of the sensitivity analysis are also presented, showing model output using recharge rate determined by the Cape Cod Commission (CCC) and zero recharge. ...............71 Figure VI-7. Model total nitrogen calibration target values are plotted against measured concentrations, together with the unity line, for the simulation period from May through November 2004.. Computed correlation (R2) and error (rms) for the model are also presented................................................71 Massachusetts Estuaries Project v Figure VII-1. Average watercolumn respiration rates (micro-Molar/day) from water collected throughout the Popponesset Bay System (Schlezinger and Howes, unpublished data). Rates vary ~7 fold from winter to summer as a result of variations in temperature and organic matter availability....................77 Figure VII-2. Aerial Photograph of the Sesachacha Pond system in Falmouth showing locations of Dissolved Oxygen mooring deployments conducted in the summer of 2002. .................................................................................................77 Figure VII-3. Bottom water record of dissolved oxygen at the Sesachacha Pond station, summer 2002. Calibration samples represented as red dots. ................79 Figure VII-4. Bottom water record of chlorophyll-a at the Sesachacha Pond station, summer 2002. Calibration samples represented as red dots..............................79 Figure VII-5. Aerial photograph of the Sesachacha Pond system showing location of benthic infaunal sampling stations (red symbol). Station 1 in each of the transects is at the southern end of the pond (bottom).........................................82 Figure VIII-1. Comparison of measured (black circles) and modeled (red triangles) salinities through the summer of 2003 (R2=0.74, RMS error=1.31 ppt). Present conditions with pond openings in Spring and Fall..................................87 Figure VIII-2. Comparison of measured (black circles) and modeled (red triangles) TN concentrations through the summer of 2003 (R2=0.83, RMS error=0.13 mg/L). Present conditions with pond openings in Spring and Fall......................88 Figure VIII-3. Comparison of modeled 2003 salinities for case where the pond is breached only in the spring (thick black dot-dashed line) and also when it is breached an additional time mid-summer. Model results for the following 2004 spring- to-fall season (thin red dash dot line) show how salinities change if the mid-summer breach is performed again. ........................89 Figure VIII-4. Comparison of modeled 2003 TN for case where the pond is breached only in the spring (thick black line) and also when it is breached an additional time mid-summer (dot-dashed line). Model results for the following 2004 spring- to-fall season (thin red dash dot line) show how TN concentrations change if the mid-summer breach is performed again................89 Massachusetts Estuaries Project vi LIST OF TABLES Table IV-1. Primary Nitrogen Loading Factors used in the Sesachacha Pond MEP analyses. General factors are from MEP modeling evaluation (Howes & Ramsey 2001). Site-specific factors are derived from Barnstable data. *Data from MEP lawn study in Falmouth, Mashpee & Barnstable 2001. ............34 Table IV-2. Sesachacha Pond Nitrogen Loads. All values are kg N yr-1...............................37 Table IV-3. Rates of net nitrogen return from sediments to the overlying waters of Sesachacha Pond. These values are combined with the basin areas to determine total nitrogen mass in the water quality model (see Chapter VI). Measurements represent July -August rates. N = number of sites .....................44 Table V-1. Tide datums reported by NOAA for Nantucket Harbor. Datum elevations are given relative to MLLW..................................................................................55 Table VI-1. Measured nitrogen concentrations and salinities for the Sesachacha Pond estuarine. “Data mean” values are calculated as the average of the separate yearly means. Data represented in this table were collected in 1992 through 2005 in Sesachacha Pond and the summer of 2005 in the Atlantic Ocean (offshore Pleasant Bay Inlet).......................................................64 Table VI-2. Sub-embayment and surface water loads used for total nitrogen modeling of Sesachacha Pond, with total watershed N loads, atmospheric N loads, and benthic flux. These loads represent present loading conditions for the listed sub-embayments..................................................................................67 Table VI-3. Model TN concentrations and salinities verses inlet days open. For modeled Spring though Fall 2004 conditions. .....................................................72 Table VI-4. Comparison of sub-embayment watershed loads used for modeling of present, build-out (scenarios “A” and “B”), and no-anthropogenic (“no- load”) loading scenarios of Sesachacha Pond. These loads do not include direct atmospheric deposition (onto the sub-embayment surface) or benthic flux loading terms. ..............................................................................72 Table VI-5. Build-out scenario sub-embayment and surface water loads used for total nitrogen modeling of the Sesachacha Pond system, with total watershed N loads, atmospheric N loads, and benthic flux.................................73 Table VI-6. “No anthropogenic loading” (“no load”) sub-embayment and surface water loads used for total nitrogen modeling of the Sesachacha Pond system, with total watershed N loads, atmospheric N loads, and benthic flux.......................................................................................................................73 Table VII-1. Percent of time during deployment of in situ sensors that bottom water oxygen levels were below various benchmark oxygen levels. ............................80 Table VII-2. Duration (% of deployment time) that chlorophyll a levels exceed various benchmark levels within the embayment system. “Mean” represents the average duration of each event over the benchmark level and “S.D.” its standard deviation. Data collected by the Coastal Systems Program, SMAST................................................................................................................80 Table VII-3. Benthic infaunal community data for the Sesachacha Pond embayment system. Estimates of the number of species adjusted to the number of individuals and diversity (H’) and Evenness (E) of the community allow comparison between locations. Samples represent surface area of 0.018 m2, N/A indicates that numbers of individuals prevent calculation of species numbers @ 75 individuals......................................................................83 Massachusetts Estuaries Project vii Table VIII-1. Summary of Nutrient Related Habitat Health within the Sesachacha Pond Estuary on the eastern coast of Nantucket Island within the Town of Nantucket, MA, based upon assessment data presented in Chapter VII. The system is presently structured as a great salt pond consisting of a single basin formed from seawater entry to a coastal kettle pond.......................85 MASSACHUSETTS ESTUARIES PROJECT 1 I. INTRODUCTION The Sesachacha Pond Embayment is a simple estuary located within the Town of Nantucket on the Island of Nantucket, Massachusetts. Sesachacha Pond is stabilized as an estuarine system by periodic management breaching of the barrier beach which separates the salt pond from the marine waters of the Atlantic Ocean (Figure I-1 and I-2). The Pond is breached 2-3 times per year to lower its nitrogen levels and raise its salinity through the exchange of brackish pond waters with the high quality offshore waters. Pond openings are also to allow the entry of marine larvae and potentially herring. Studies of Sesachacha Pond in the late 1980's indicated that periodic tidal exchange was required to help stabilize the ecology. Data indicated that not breaching the Pond regularly for management would result in long term cycling of pond waters between saline and near freshwater (~1 ppt), due to the freshening by groundwater inflow and periodic storm inflows of salt water (Howes and Goehringer 1989). This salinity cycling would result in highly unstable conditions and impairment of habitat quality. The natural breaching of the barrier beach was subsequently observed during Hurricane Bob in 1991. Sesachacha Pond has been breached for management purposes for more than a century, with greater and lesser success. However, it is clear that the health of this estuary's habitats are dependent on the amount and timing of periodic tidal exchanges. One of the goals of the MEP analysis was to determine the best protocol for pond openings aimed at producing the highest quality habitat within this embayment. Figure I-1. Location of the Sesachacha Pond system, Island of Nantucket, Town of Nantucket, Massachusetts. Sesachacha Pond is a great salt pond, historically maintained by periodic breaching of the barrier beach to allow exchange with Atlantic Ocean waters. Sesachacha Pond, Nantucket, MA. MASSACHUSETTS ESTUARIES PROJECT 2 Figure I-2. Study region for the Massachusetts Estuaries Project analysis of the Sesachacha Pond System. Tidal waters enter the Pond from the Atlantic Ocean during periodic openings of the barrier beach. Freshwaters enter from the watershed primarily through direct groundwater discharge and direct precipitation. Sesachacha Pond is approximately 6.0 miles northeast of the Nantucket town center and its watershed abuts the watershed to Nantucket Harbor. Sesachacha Pond is situated on the eastern coast of Nantucket Island between Squam Head and Sankaty Head. The watershed to Sesachacha Pond is fully within the Town of Nantucket, making Nantucket the sole municipal steward of this small estuary. Virtually all watershed freshwater and nutrients enter Sesachacha Pond via groundwater seepage, as there are no significant surface inflows to this system. As a result, there is little opportunity for nitrogen removal during transport from watershed source to estuarine waters. Sesachacha Pond is comprised of a single basin and a narrow barrier beach which is periodically breached to the Atlantic Ocean for pond management. The open water area of 255-267 acres makes Sesachacha Pond a great salt pond. Sesachacha Pond was formed by the flooding of a kettle pond as a result of rising sea level following the last glaciation approximately 18,000 years BP. Sesachacha Pond consists of two deep "holes", reaching a maximum depth of 6.6 meters, and 3 functional sub-basin areas. The pond is approximately 1,320 meters long and is oriented north-northeast paralleling the shore of the Atlantic Ocean. The maximum width of the pond is 1,200 meters with an irregular shore that makes for an average width of approximately 850 meters. The pond possesses approximately 5.5 kilometers of shoreline, 870 meters of which is on the inland shore of the barrier beach separating the Pond from the Atlantic Ocean. The Pond is non-tidal and the salinity is maintained by periodic breaching of the barrier beach by the Town. Water levels vary from a low immediately after a breaching event and a high after an extended period of closure, which allows groundwater inflow to raise pond levels and dilute the salinity of pond waters. Sesachahcha Pond Quidnet Polpis Road Hoicks Hollow Sesachahcha Pond Quidnet Polpis Road Hoicks Hollow Breach MASSACHUSETTS ESTUARIES PROJECT 3 Sesachacha Pond is predominantly groundwater fed with no significant surface inflows of freshwater. The Town openings of the channel from the Pond to the Atlantic Ocean is to enhance flushing of the Pond, maintain "acceptable" levels of salinity and nitrogen within the Pond waters and to allow for entry of marine organisms (e.g. fish and larvae). Generally, Sesachacha Pond is a brackish waterbody with salinities ranging between 10 – 25 ppt with salinities increasing to approximately 32 ppt during times when the Pond is opened to the Atlantic Ocean. Analysis of the long term record of the surface water salinity of the Pond indicates that with proper management salinities can be maintained at levels >20 ppt (Chapter VI). Recent Management History: Historically, Sesachacha Pond has been opened to tidal exchange each spring and fall to maintain salinity, manage nutrients and to allow passage of marine larvae and herring. The pond was not opened from 1981-1991, resulting in a freshening of Pond waters and a loss of all marine species (Howes and Goehringer 1989). After a decision to again manage the Pond as a “marine” resource area, the pond has been opened to Atlantic Ocean waters each spring and fall over the past decade, with openings persisting for 3.5 to 25 days per year (Curley 2004). During closed periods, groundwater inflow dilutes pond salinities periodically to ~10 ppt and raises pond levels by several feet. Water quality within this system is primarily controlled by the frequency and duration of openings to tidal exchange. There is very little nitrogen loading from development within the relatively small watershed to this great salt pond system and atmospheric deposition of nitrogen is the major source of external nitrogen to pond waters (Chapter IV). The embayment has traditionally been managed as a source of seed shellfish, although there are anecdotal reports of significant shellfish harvest from this system. Based on the soundings, the depth of Sesachacha Pond averages approximately 5.5 meters. There are two deep basins (basin 1 and basin 2) 6.6 meters and 6.1 meters respectively, with a third less distinct basin being shallower, 4.3 m (Figure I-3). Basin 1 is the deepest of the three basins making up Sesachacha Pond and is situated in the northeastern quadrant of the pond closest to the location of historical and future breaches of the barrier beach. Moreover, this deepest of the three basins is closest to the area of the pond that supports the greatest extent of residential development. While Sesachacha Pond presently has a relatively low nitrogen load from its watershed, due to its small watershed and proportionally large undeveloped areas, it is still significantly impaired by nitrogen enrichment and is clearly eutrophic. This apparent paradox results from its very low tidal exchange rate due to barrier beach processes closing the inlet to the Atlantic Ocean on an annual basis. As presented in a Sesachacha Pond 1989 Draft Environmental Impact Report (EIR), the barrier beach separating Sesachacha Pond from the Atlantic Ocean was dredged out once and sometimes twice per year as far back as the 1930’s. This cycle of periodic openings continued generally uninterrupted up until 1981. The man-made breach to the pond was developed using the hydraulic gradient between the pond and the ocean to create a rapid outflow of pondwater to scour a channel in the barrier beach to a depth low enough to allow tidal exchange to occur for as long as possible (1-14 days). Infrequently the opening was reported to have stayed open for longer than two weeks. These periodic openings were undertaken as a means of controlling salinity in the pond in order to safeguard shellfish resources as well as allow for the passage of finfish into the pond, lower pond levels as a flood control measure, and allow nutrient rich waters to flush out of the pond as a water quality control measure. MASSACHUSETTS ESTUARIES PROJECT 4 Figure I-3. Sesachacha Pond bathymetry depicting major basins, Town of Nantucket, Massachusetts (EIR 1989). In the early 1980’s ownership of the land that constitutes the barrier beach resided with a Mrs. Evans who reportedly initiated a study of the impact of periodic breaching on the pond. A hydrogeologic investigation of Sesachacha Pond was completed in 1985 (Perkins Jordan 1985), with the goal of understanding the interaction of the pond with surrounding groundwater and evaluate the long term changes in the quality of the pond water due to opening the pond to the ocean. It was reported in the 1989 Draft EIR of Sesachacha Pond that based on the findings of the hydrogeologic study, annual dredging of the pond was suspended for a period of time. In 1987, the barrier beach property changed ownership (Greenhill) at which point outstanding questions related to the value of pond openings on maintaining the ecological function of the system resurfaced. To address the pond opening issue, a scientific study to determine the likely impacts of various pond management alternatives on Sesachacha Pond and surrounding wetlands was initiated by the Greenhills and the Massachusetts Audubon Society. Based upon the data generated by this effort showing that the Pond habitats are best managed as estuarine Basin 1 Basin 2 Basin 3 MASSACHUSETTS ESTUARIES PROJECT 5 resources and that periodic opening are required to achieve the needed conditions. The 1989 EIR was developed and the Pond once again was breached for management. As presented in various Sesachacha Pond Annual Reports (as far back as 1992) developed by the Town of Nantucket Shellfish and Marine Department, the Pond again opened in 1991 and periodically opened in each subsequent year to allow exchange with Atlantic Ocean water. However, the highly restricted "flushing" of pond waters per annum serves to greatly increase the nitrogen sensitivity of this system, such that even low rates of nitrogen loading cause eutrophic conditions. The difficulty in achieving adequate tidal exchange during any given opening attempt has resulted in the present ecological impairment of the Sesachacha Pond System. The low rate of nitrogen removal through tidal flushing results in high nitrogen levels, large phytoplankton blooms and periodic anoxia of bottom waters. It is clear that restoration of Sesachacha Pond will require evaluating the timing and duration of the periodic openings that would achieve the highest habitat quality within this system, relative to the logistical realities involved. Although the nitrogen load to Sesachacha Pond is relatively low and dominated by atmospheric inputs, nitrogen management still needs to be evaluated in the development of the restoration and management plan. The Town of Nantucket has been among the steadily growing towns in the Commonwealth over the past two decades and does have a centralized wastewater treatment system that services the town center. However, the Sesachacha Pond watershed, being situated in a relatively remote and undeveloped area of the Island is not connected to any municipal sewerage system, but relies on privately maintained septic systems for treatment and disposal of wastewater. As existing and probable increasing levels of nutrients impact Nantucket’s coastal embayments, water quality degradation will accelerate, with further harm to invaluable environmental resources. As the stakeholder to the Sesachacha Pond System, the Town of Nantucket and its citizens have been active in promoting restoration of the coastal embayment systems of the Island. This local concern also led to the conduct of several studies (Section Chapter II) to support monitoring and restoration and the Town is presently willing to implement an appropriate plan for estuarine restoration. To this end, the Town of Nantucket Water Quality Monitoring Program was provided technical assistance by the Coastal Systems Program at SMAST-UMD and over the past several years has been able to develop a significant baseline of water quality in the embayments of the Island inclusive of Sesechacha Pond. This effort provides the quantitative water column nitrogen data (1988-89; 2000-2005) required for the implementation of the MEP’s Linked Watershed-Embayment Approach used in the present study. The common focus of the Nantucket water quality monitoring effort has been to gather site-specific data on the current nitrogen related water quality throughout the Sesachacha Pond System and determine its relationship to tidal flushing when the pond is opened to the ocean. This multi-year effort has provided the baseline information required for determining the link between upland loading, tidal flushing, and estuarine water quality. The MEP effort builds upon the Water Quality Monitoring Program, previous hydrodynamic studies and water quality analyses and includes high order biogeochemical analyses and water quality modeling necessary to develop critical nitrogen targets for each major sub-embayment. These critical nitrogen targets and the link to specific ecological criteria form the basis for the nitrogen threshold limits necessary to develop and implement management alternatives needed by the Town of Nantucket for estuarine restoration/protection. While the completion of this complex multi-step process of rigorous scientific investigation to support watershed and tidal flushing MASSACHUSETTS ESTUARIES PROJECT 6 based nitrogen management plans has taken place under the programmatic umbrella of the Massachusetts Estuaries Project, the results stem directly from the efforts of large number of Town staff and citizens over many years, most notably within the Shellfish and Marine Department, as well as the riparian land owners (most notably the Evans and Greenhills) and non-governmental entities such as the Nantucket Land Council. The modeling tools developed as part of this program provide the quantitative information necessary for the Town of Nantucket to develop and evaluate the most cost effective management alternatives to restore this coastal resource. Given this extensive prior data collection effort by the Town of Nantucket and its citizens, the MEP Technical Team conducted its analysis of Sesachacha Pond using Commonwealth matching funds at no additional cost to the Town. I.1 THE MASSACHUSETTS ESTUARIES PROJECT APPROACH Coastal embayments throughout the Commonwealth of Massachusetts (and along the U.S. eastern seaboard) are becoming nutrient enriched. The nutrients are primarily related to changes in watershed land-use associated with increasing population within the coastal zone over the past half century. Many of Massachusetts’ embayments have nutrient levels that are approaching or are currently over this assimilative capacity, which begins to cause declines in their ecological health. The result is the loss of fisheries habitat, eelgrass beds, and a general disruption of benthic communities and the food chain which they support. At higher levels, enhanced nitrogen loading from surrounding watersheds causes aesthetic degradation and inhibits even recreational uses of coastal waters. In addition to nutrient related ecological declines, an increasing number of embayments are being closed to swimming, shellfishing and other activities as a result of bacterial contamination. While bacterial contamination does not generally degrade the habitat, it restricts human uses. However like nutrients, bacterial contamination is frequently related to changes in land-use as watersheds become more developed. The regional effects of both nutrient loading and bacterial contamination span the spectrum from environmental to socio-economic impacts and have direct consequences to the culture, economy, and tax base of Massachusetts’s coastal communities. The primary nutrient causing the increasing impairment of the Commonwealth’s coastal embayments is nitrogen and the primary sources of this nitrogen are wastewater disposal, fertilizers, and changes in the freshwater hydrology associated with development. At present there is a critical need for state-of-the-art approaches for evaluating and restoring nitrogen sensitive and impaired embayments. Within Southeastern Massachusetts alone, almost all of the municipalities (as is the case with the Town of Nantucket) are grappling with Comprehensive Wastewater Planning and/or environmental management issues related to the declining health of their estuaries. Municipalities are seeking guidance on the assessment of nitrogen sensitive embayments, as well as available options for meeting nitrogen goals and approaches for restoring impaired systems. Many of the communities have encountered problems with “first generation” watershed based approaches, which do not incorporate estuarine processes. The appropriate method must be quantitative and directly link watershed and embayment nitrogen conditions. This “Linked” Modeling approach must also be readily calibrated, validated, and implemented to support planning. Although it may be technically complex to implement, results must be understandable to the regulatory community, town officials, and the general public. The Massachusetts Estuaries Project represents the next generation of watershed based nitrogen management approaches. The Massachusetts Department of Environmental Protection (MA DEP), the University of Massachusetts – Dartmouth School of Marine Science MASSACHUSETTS ESTUARIES PROJECT 7 and Technology (SMAST), and others including the Cape Cod Commission (CCC) have undertaken the task of providing a quantitative tool for watershed-embayment management for communities throughout Southeastern Massachusetts. The Massachusetts Estuary Project is founded upon science-based management. The Project is using a consistent, state-of-the-art approach throughout the region’s coastal waters and providing technical expertise and guidance to the municipalities and regulatory agencies tasked with their management, protection, and restoration. The overall goal of the Massachusetts Estuaries Project is to provide the DEP and municipalities with technical guidance to support policies on nitrogen management of their embayments. In addition, the technical reports prepared for each embayment system will serve as the basis for the development of Total Maximum Daily Loads (TMDLs). Development of TMDLs is required pursuant to Section 303(d) of the Federal Clean Water Act. TMDLs must identify sources of the pollutant of concern (in this case nitrogen) from both point and non-point sources, the allowable load to meet the state water quality standards and then allocate that load to all sources taking into consideration a margin of safety, seasonal variations, and several other factors. The TMDL includes the role of nitrogen removal through tidal flushing, not just watershed nitrogen loading rates. In addition, each TMDL must contain an outline of an implementation plan. For this project, the DEP recognizes that there are likely to be multiple ways to achieve the desired goals, some of which are more cost effective than others and therefore, it is extremely important for each Town to further evaluate potential options suitable to their community. As such, DEP will likely be recommending that specific activities and timelines be further evaluated and developed by the Towns (sometimes jointly) through the Comprehensive Wastewater Management Planning process. However, it is absolutely clear that any remediation of the nitrogen related impairment presently within Sesachacha Pond must include an evaluation of periodic breaching. In appropriate estuaries, TMDL’s for bacterial contamination will also be conducted in concert with the nutrient effort (particularly if there is a 303d listing). In these cases, the MEP (through SMAST) will produce a Technical Analysis and Report to support a bacterial TMDL for the system from which MA DEP develops the TMDL. The goal of the bacterial program is to provide information to guide targeted sampling for specific source identification and remediation. In contrast to the bacterial program, the MEP nitrogen program also includes site-specific habitat assessments and watershed/embayment modeling approaches to develop and assess various nitrogen management alternatives for meeting selected nitrogen goals supportive of restoration/protection of embayment health. The major MEP nitrogen management goals are to: • provide technical analysis and supporting documentation to Towns as a basis for sound nutrient management decision making towards embayment restoration • develop a coastal TMDL working group for coordination and rapid transfer of results, • determine the nutrient sensitivity of each of the 89 embayments in Southeastern MA • provide necessary data collection and analysis required for quantitative modeling, • conduct quantitative TMDL analysis, outreach, and planning, • keep each embayment’s model “alive” to address future municipal needs. The core of the Massachusetts Estuaries Project analytical method is the Linked Watershed-Embayment Management Modeling Approach. This approach represents the “next MASSACHUSETTS ESTUARIES PROJECT 8 generation” of nitrogen management strategies. It fully links watershed inputs with embayment circulation and nitrogen characteristics. The Linked Model builds on and refines well accepted basic watershed nitrogen loading approaches such as those used in the Buzzards Bay Project, the CCC models, and other relevant models. However, the Linked Model differs from other nitrogen management models in that it: • requires site specific measurements within each watershed and embayment; • uses realistic “best-estimates” of nitrogen loads from each land-use (as opposed to loads with built-in “safety factors” like Title 5 design loads); • spatially distributes the watershed nitrogen loading to the embayment; • accounts for nitrogen attenuation during transport to the embayment; • includes a 2D or 3D embayment circulation model depending on embayment structure; • accounts for basin structure, tidal variations, and dispersion within the embayment; • includes nitrogen regenerated within the embayment; • is validated by both independent hydrodynamic, nitrogen concentration, and ecological data; • is calibrated and validated with field data prior to generation of “what if” scenarios. The Linked Model has been applied for watershed nitrogen management in approximately 15 embayments throughout Southeastern Massachusetts. In these applications it has become clear that the Linked Model Approach’s greatest assets are its ability to be clearly calibrated and validated, and its utility as a management tool for testing “what if” scenarios for evaluating watershed nitrogen management options. The Linked Watershed-Embayment Model when properly parameterized, calibrated and validated for a given embayment becomes a nitrogen management planning tool, which fully supports TMDL analysis. The Model facilitates the evaluation of nitrogen management alternatives relative to meeting water quality targets within a specific embayment. The Linked Watershed-Embayment Model also enables Towns to evaluate improvements in water quality relative to the associated cost. In addition, once a model is fully functional it can be “kept alive” and updated for continuing changes in land-use or embayment characteristics (at minimal cost). In addition, since the Model uses a holistic approach (the entire watershed, embayment and tidal source waters), it can be used to evaluate all projects as they relate directly or indirectly to water quality conditions within its geographic boundaries. Linked Watershed-Embayment Model Overview: The Model provides a quantitative approach for determining an embayment’s: (1) nitrogen sensitivity, (2) nitrogen threshold loading levels (TMDL) and (3) response to changes in nitrogen loading rate or nitrogen removal through enhance tidal flushing. The approach is both calibrated and fully field validated and unlike many approaches, accounts for nutrient sources, attenuation, and recycling and variations in tidal hydrodynamics (Figure I-4). This methodology integrates a variety of field data and models, specifically: • Watercolumn Monitoring - multi-year embayment nutrient sampling • Hydrodynamics - - embayment bathymetry - site specific tidal record - current records (in complex systems only) - hydrodynamic model • Watershed Nitrogen Loading - watershed delineation MASSACHUSETTS ESTUARIES PROJECT 9 - stream flow (Q) and nitrogen load - land-use analysis (GIS) - watershed N model • Embayment TMDL - Synthesis - linked Watershed-Embayment N Model - salinity surveys (for linked model validation) - rate of N recycling within embayment - D.O record - Macrophyte survey - Infaunal survey I.2 SITE DESCRIPTION Sesachacha Pond is a "simple" estuary, with a single basin and occasionally open tidal inlet. The open water area of 267 acres, makes Sesachacha Pond a great salt pond. The Sesachacha Pond System presently exchanges tidal water only during periodic opening through the barrier beach, primarily as part of a management program and occasionally during major storms. Sesachacha Pond has been breached for management purposes for more than a century, with greater and lesser success. It is clear that the health of this estuary's habitats are dependent on the amount and timing of periodic tidal exchanges. For the MEP analysis, Sesachacha Pond is the principal estuarine basin in the modeling and thresholds analysis. Sesachacha Pond presently has a relatively low nitrogen load from its watershed, due to its small watershed and proportionally large undeveloped areas. It is still significantly impaired by nitrogen enrichment and is clearly eutrophic (Section VII). This apparent paradox results from its very low tidal exchange rate, resulting from barrier beach processes closing the inlet to the Atlantic Ocean on an annual basis. As presented in a Sesachacha Pond 1989 Draft Environmental Impact Report (EIR), the barrier beach separating Sesachacha Pond from the Atlantic Ocean was breached once and sometimes twice per year as far back as the 1930’s. This cycle of periodic openings continued generally uninterrupted up until 1981. The man-made breach to the pond was developed using the hydraulic gradient between the pond and the ocean to create a rapid outflow of pondwater to scour a channel in the barrier beach to a depth low enough to allow tidal exchange to occur for as long as possible (1-14 days). Infrequently the opening was reported to have stayed open for longer than two weeks. These periodic openings were undertaken as a means of controlling salinity in the pond in order to safe guard shellfish resources as well as allow for the passage of finfish into the pond, lower pond levels as a flood control measure, and allow nutrient rich waters to flush out of the pond as a water quality control measure. However, the highly restricted "flushing" of pond waters per annum serves to greatly increase the nitrogen sensitivity of this system, such that even low rates of nitrogen loading cause eutrophic conditions. The difficulty in achieving adequate tidal exchange during any given opening attempt has resulted in the present ecological impairment of the Sesachacha Pond System. The low rate of nitrogen removal through tidal flushing results in high nitrogen levels, large phytoplankton blooms and periodic anoxia of bottom waters. It is clear that restoration of Sesachacha Pond will require evaluating the timing and duration of the periodic openings that would achieve the highest habitat quality within this system, relative to the logistical realities involved. As management alternatives are being developed and evaluated, it is important to note that the Sesachacha Pond System is naturally a relatively dynamic system and has undergone significant alterations to its hydrologic and biological systems over the past 100 years. Within MASSACHUSETTS ESTUARIES PROJECT 10 such dynamic systems, restoration alternatives need to be evaluated relative to the system’s “maximum level of sustainable environmental health” in addition to traditional standards. While the nutrient related health of Sesachacha Pond as it exists today is linked to changes wrought by natural processes and human activities, it is the physical structure of the system laid down by the retreat of the Laurentide Ice Sheet that still controls much of the Systems’ tolerance to nutrient inputs. The physical structure, shape and depth of a coastal embayment plays a major role in its susceptibility to ecological impacts from nutrient loading. Physical structure (geomorphology), which includes embayment bathymetry, isolation by the barrier beach and presence of saltwater reaches, when coupled with the tidal range of the adjacent open waters which helps drive the periodic flushing, all come together to define the dynamics of the system. System flushing rate is generally the primary factor for removing nutrients from active cycling within coastal bays and harbors. As a result maximizing system flushing is one of the standard approaches for controlling the nutrient related health of coastal embayments in general and Sesachacha Pond specifically. The present configuration of the Sesachacha Pond system is relatively new in the coastal landscape, as the eastern coast of Nantucket Island is a dynamic region, where natural wave and tidal forces continue to reshape the shoreline (see Section V). All the while, Sesachacha Pond was formed by the flooding of a kettle pond as a result of rising sea level following the last glaciation, approximately 18,000 years BP. While Sesachacha Pond presently has a relatively low nitrogen load from its watershed, due to its small size and proportionally large undeveloped areas, it is still significantly impaired by nitrogen enrichment. In addition, the proportionally large estuarine surface area results in a dominance of the external nitrogen loading being through direct atmospheric deposition to embayment waters. Even so, the total external nitrogen load to this great salt pond is low yet the system is eutrophic. This apparent paradox results from the low rate of annual tidal flushing which serves to greatly increase the nitrogen sensitivity of this system. The inability of generate complete exchange of pond waters with normal breaching operations, has caused significant ecological degradation of the Pond System. The low rate of nitrogen removal through tidal flushing results in high nitrogen levels, large phytoplankton blooms and periodic anoxia of bottom waters. It is clear that restoration of Sesachacha Pond will require addressing the management openings, especially as the system has historically operated as a salt pond and its proximity to the Atlantic Ocean prevents its management as a freshwater system due to periodic overwash of salt water (similar to Oyster Pond, Falmouth, and Rushy Marsh, Barnstable see MEP Technical Reports 2005, 2006). MASSACHUSETTS ESTUARIES PROJECT 11Nitrogen Thresholds AnalysisNitrogen Thresholds AnalysisThresholds Thresholds DevelopmentDevelopmentSection IXSection IXD.O., Eelgrass Infauna SurveysSection VIIWatershed Delineation & N LoadSection III and IVBenthic Flux and Water Column MeasurementsSection IVTotal Nitrogen ModelingSection VIHydrodynamic ModelingSection VTide, Bathymetry, and Current Measurements Figure I-4. Massachusetts Estuaries Project Critical Nutrient Threshold Analytical Approach MASSACHUSETTS ESTUARIES PROJECT 12 I.3 NUTRIENT LOADING Surface and groundwater flows are pathways for the transfer of land-sourced nutrients to coastal waters. Fluxes of primary ecosystem structuring nutrients, nitrogen and phosphorus, differ significantly as a result of their hydrologic transport pathway (i.e. streams versus groundwater). In sandy glacial outwash aquifers, such as in the watershed to the Sesachacha Pond System, phosphorus is highly retained during groundwater transport as a result of sorption to aquifer minerals (Weiskel and Howes 1992). Since even Cape Cod, Nantucket and Martha’s Vineyard “rivers” are primarily groundwater fed, watersheds tend to release little phosphorus to coastal waters. In contrast, nitrogen, primarily as plant available nitrate, is readily transported through oxygenated groundwater systems on Cape Cod (DeSimone and Howes 1996, Weiskel and Howes 1992, Smith et al. 1991). The result is that terrestrial inputs to coastal waters tend to be higher in plant available nitrogen than phosphorus (relative to plant growth requirements). However, coastal estuaries tend to have algal growth limited by nitrogen availability, due to their flooding with low nitrogen coastal waters (Ryther and Dunstan 1971). Though Sesachacha Pond is only occasionally opened to the ocean, the system as a “tidally restricted” coastal embayment presently follows this general pattern, where the primary nutrient of eutrophication in the system is nitrogen. Nutrient related water quality decline represents one of the most serious threats to the ecological health of the nearshore coastal waters. Coastal embayments, because of their enclosed basins, shallow waters and large shoreline area, are generally the first indicators of nutrient pollution from terrestrial sources. By nature, these systems are highly productive environments, but nutrient over-enrichment of these systems worldwide is resulting in the loss of their aesthetic, economic and commercially valuable attributes. Each embayment system maintains a capacity to assimilate watershed nitrogen inputs without degradation. However, as loading increases a point is reached at which the capacity (termed assimilative capacity) is exceeded and nutrient related water quality degradation occurs. This point can be termed the “nutrient threshold” and in estuarine management this threshold sets the target nutrient level for restoration or protection. Because nearshore coastal salt ponds and embayments are the primary recipients of nutrients carried via surface and groundwater transport from terrestrial sources, it is clear that activities within the watershed, often miles from the water body itself, can have chronic and long lasting impacts on these fragile coastal environments. Protection and restoration of coastal embayments from nitrogen overloading has resulted in a focus on determining the assimilative capacity of these aquatic systems for nitrogen. While this effort is ongoing (e.g. USEPA TMDL studies), southeastern Massachusetts has been the site of intensive efforts in this area (Eichner et al., 1998, Costa et al., 1992 and in press, Ramsey et al., 1995, Howes and Taylor, 1990, and the Falmouth Coastal Overlay Bylaw). While each approach may be different, they all focus on changes in nitrogen loading from watershed to embayment, and aim at projecting the level of increase in nitrogen concentration within the receiving waters. Each approach depends upon estimates of circulation within the embayment; however, few directly link the watershed and hydrodynamic models, and virtually none include internal recycling of nitrogen (as was done in the present effort). However, determination of the “allowable N concentration increase” or “threshold nitrogen concentration” used in previous studies had a significant uncertainty due to the need for direct linkage of watershed and embayment models and site-specific data. In the present effort we have integrated site-specific data on nitrogen levels and the gradient in N concentration throughout MASSACHUSETTS ESTUARIES PROJECT 13 the Sesachacha Pond System monitored by the Town of Nantucket Water Quality Monitoring Program, with site-specific habitat quality data (D.O., eelgrass, phytoplankton blooms, benthic animals) utilized to refine the general nitrogen thresholds typically used by the Cape Cod Commission, Buzzards Bay Project, and Massachusetts State Regulatory Agencies. Unfortunately, Sesachacha Pond is presently beyond its ability to assimilate additional nutrients without further impairing the ecological health of this aquatic resource. This is in significant part due to the very restricted tidal exchange with Atlantic Ocean waters. Nitrogen levels are elevated, eelgrass beds have not been observed within Sesachacha Pond for the past half century or longer and there are large summer phytoplankton blooms and periodic hypoxia of bottom waters. The result is that nitrogen management of the Sesachacha Pond system is aimed at restoration, not protection or maintenance of existing conditions. In general, nutrient over-fertilization is termed “eutrophication” and when the nutrient loading is primarily from human activities, “cultural eutrophication”. Although the influence of human-induced changes has increased nitrogen loading to the systems and contributed to the degradation in ecological health, it is possible in systems like Sesachacha Pond that eutrophication occurs with only minor influence of humankind, which must be considered in the nutrient threshold analysis. While this finding would not change the need for restoration, it would change the approach and potential targets for management. As part of future restoration efforts, it is important to understand that it may not be possible to turn each embayment into a “pristine” system. In addition, to the impairment of Sesachacha Pond’s sub-tidal habitats, there has been a loss of emergent salt marsh from the system stemming from the restricted tidal exchange in recent years. I.4 WATER QUALITY MODELING Evaluation of upland nitrogen loading provides important “boundary conditions” (e.g. watershed derived and offshore nutrient inputs) for water quality modeling of the Sesachacha Pond System; however, a thorough understanding of hydrodynamics is required to accurately determine nitrogen concentrations within each system. Therefore, water quality modeling of even periodically tidal estuaries must include a thorough evaluation of the hydrodynamics. Estuarine hydrodynamics control a variety of coastal processes including tidal flushing, pollutant dispersion, tidal currents, sedimentation, erosion, and water levels. Numerical models provide a cost-effective method for evaluating tidal hydrodynamics since they require limited data collection and may be utilized to numerically assess a range of management alternatives. Once the hydrodynamics of an estuary system are understood, computations regarding the related coastal processes become relatively straightforward extensions to the hydrodynamic modeling. The spread of pollutants may be analyzed from tidal current information developed by the numerical models. In the case of Sesachacha Pond, the hydrodynamic analysis is tailored to the fact that the pond is essentially a closed system for larger periods of the year with periodic openings that drive the circulation, mixing and exchange of pond waters with Atlantic Ocean water. The MEP water quality evaluation examined the potential impacts of nitrogen loading into Sesachacha Pond under a variety of nitrogen input (loading) and hydrodynamic conditions (breaches of the barrier beach). A two-dimensional depth-averaged hydrodynamic model based upon the tidal currents resulting from barrier beach breaching, groundwater inflow to the pond and water elevations (both actual and projected under various breaching scenarios) was employed. Once the hydrodynamic properties of the estuarine system were computed, two- dimensional water quality model simulations were used to predict the dispersion of the nitrogen at current loading rates. MASSACHUSETTS ESTUARIES PROJECT 14 Using standard dispersion relationships for estuarine systems of this type, the water quality model and the hydrodynamic models were then integrated in order to generate estimates regarding the spread of total nitrogen from the site-specific hydrodynamic properties. The distributions of nitrogen loads from watershed sources were determined from land-use analysis, based upon watershed delineations and groundwater elevations (Section 3). Almost all nitrogen entering the Sesachacha Pond System is transported by freshwater, both through atmospheric deposition and through groundwater discharge. Concentrations of total nitrogen and salinity of Atlantic Ocean source waters and throughout Sesachacha Pond were taken from the Water Quality Monitoring Program (a coordinated effort between the Town of Nantucket, Coastal Systems Program at SMAST and others). Measurements of current salinity and nitrogen and salinity distributions throughout estuarine waters of the Systems (2000-2005), coupled to long- term salinity records were used to calibrate and validate the water quality model (under existing loading conditions). I.5 REPORT DESCRIPTION This report presents the results generated from the implementation of the Massachusetts Estuaries Project linked watershed-embayment approach to the Sesachacha Pond System for the Town of Nantucket. A review of existing water quality studies is provided (Section II). The development of the watershed delineations and associated detailed land use analysis for watershed based nitrogen loading to the coastal system is described in Sections III and IV. In addition, nitrogen input parameters to the water quality model are described. Since benthic flux of nitrogen from bottom sediments is a critical (but often overlooked) component of nitrogen loading to shallow estuarine systems, determination of the site-specific magnitude of this component also was performed (Section IV). Nitrogen loads from the watershed and sub- watershed surrounding the estuary were derived from Cape Cod Commission, Town of Nantucket Planning Department and the Nantucket Land Council data. Offshore water column nitrogen values were derived from an analysis of monitoring stations in Nantucket Sound and the Atlantic Ocean (Section IV). Intrinsic to the calibration and validation of the linked- watershed embayment modeling approach is the collection of background water quality monitoring data (conducted by municipalities) as discussed in Section IV. Results of hydrodynamic modeling of embayment circulation are discussed in Section V and nitrogen (water quality) modeling, as well as an analysis of how the measured nitrogen levels correlate to observed estuarine water quality are described in Section VI. This analysis includes modeling of current conditions, conditions at watershed build-out, and with removal of anthropogenic nitrogen sources. In addition, an ecological assessment of the component sub-embayments was performed that included a review of existing water quality information and the results of a benthic analysis (Section VII). The modeling and assessment information is synthesized and nitrogen threshold levels developed for restoration of the Estuary in Section VIII. Additional modeling is conducted to produce an example of the type of watershed nitrogen reduction required to meet the determined Bay threshold for restoration. This latter assessment represents only one of many solutions and is produced to assist the Town in developing a variety of alternative restoration options for this system. Finally, analyses of the Sesachacha Pond System were relative to potential alterations of circulation and flushing, including an analysis to identify hydrodynamic idiosyncrasies of the pond and an examination of various breach options to improve nitrogen related water quality (and wetland communities). The results of the nitrogen modeling for each scenario have been presented (Section VIII). Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Threshold for the Hummock Pond Estuarine System, Town of Nantucket, MA University of Massachusetts Dartmouth Massachusetts Department of School of Marine Science and Technology Environmental Protection DRAFT REPORT – December 2013 Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Threshold for the Hummock Pond System, Towns of Nantucket, MA DRAFT REPORT –DECEMBER 2013 Brian Howes Roland Samimy David Schlezinger Ed Eichner John Ramsey Sean Kelley Contributors: US Geological Survey Don Walters and John Masterson Applied Coastal Research and Engineering, Inc. Elizabeth Hunt and Trey Ruthven Massachusetts Department of Environmental Protection Charles Costello SMAST Coastal Systems Program Jennifer Benson, Michael Bartlett, and Sara Sampieri Nantucket Planning and Economic Development Commission Andrew Vorce Executive Summary 1 Massachusetts Estuaries Project Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Hummock Pond, Nantucket, Massachusetts Executive Summary 1. Background This report presents the results generated from the implementation of the Massachusetts Estuaries Project’s Linked Watershed-Embayment Approach to the Hummock Pond embayment system, a coastal embayment of the Island of Nantucket within the Town of Nantucket, Massachusetts. Analyses of the Hummock Pond embayment system was performed to assist the Town with up-coming nitrogen management decisions associated with the Towns’ current update of its Comprehensive Wastewater Management Plan (CWMP), as well as wetland restoration, anadromous fish runs, shell fishery, and open-space maintenance programs. As part of the MEP approach, habitat assessment was conducted on the embayment based upon available water quality monitoring data, historical changes in eelgrass/macroalgal distribution, time-series water column oxygen measurements, and benthic community structure. Nitrogen loading thresholds for use as goals for watershed nitrogen management are the major product of the MEP effort. In this way, the MEP offers a science-based management approach to support the Town of Nantucket resource planning and decision-making process. The primary products of this effort are: (1) a current quantitative assessment of the nutrient related health of the Hummock Pond embayment, (2) identification of all nitrogen sources (and their respective N loads) to embayment waters, (3) nitrogen threshold levels for maintaining Massachusetts Water Quality Standards within embayment waters, (4) analysis of watershed nitrogen loading reduction to achieve the N threshold concentrations in embayment waters, and (5) a functional calibrated and validated Linked Watershed-Embayment modeling tool that can be readily used for evaluation of nitrogen management alternatives (to be developed by the Town) for the restoration of the Hummock Pond embayment system. Wastewater Planning: As increasing numbers of people occupy coastal watersheds, the associated coastal waters receive increasing pollutant loads. Coastal embayments throughout the Commonwealth of Massachusetts (and along the U.S. eastern seaboard) are becoming nutrient enriched. The elevated nutrients levels are primarily related to the land use impacts associated with the increasing population within the coastal zone over the past half-century. Massachusetts Department of Environmental Protection Executive Summary 2 The regional effects of both nutrient loading and bacterial contamination span the spectrum from environmental to socio-economic impacts and have direct consequences to the culture, economy, and tax base of Massachusetts’s coastal communities. The primary nutrient causing the increasing impairment of our coastal embayments is nitrogen, with its primary sources being wastewater disposal, and nonpoint source runoff that carries nitrogen (e.g. fertilizers) from a range of other sources. Nitrogen related water quality decline represents one of the most serious threats to the ecological health of the nearshore coastal waters. Coastal embayments, because of their shallow nature and large shoreline area, are generally the first coastal systems to show the effect of nutrient pollution from terrestrial sources. In particular, the Hummock Pond embayment system within the Town of Nantucket is showing clear signs of eutrophication (over enrichment) from extremely limited tidal exchange with clean Atlantic Ocean water, atmospheric deposition, flux of nutrients from bottom sediments, as well as and to a lesser extent, enhanced nitrogen loads entering through groundwater from the gradually increasing development of the watershed to this coastal system. Eutrophication is a process that occurs naturally and gradually over a period of tens or hundreds of years. However, human-related (anthropogenic) sources of nitrogen may be introduced into ecosystems at an accelerated rate that cannot be easily absorbed, resulting in a phenomenon known as cultural eutrophication. In both marine and freshwater systems, cultural eutrophication results in degraded water quality, adverse impacts to ecosystems, and limits on the use of water resources. The relatively pristine nature of Nantucket's nearshore, Harbor and pond waters has historically been a valuable asset to the island. However, concern over the potential degradation of pond and Harbor water quality began to arise, which resulted in monitoring, scientific investigations and management planning which continues to this day. While Hummock Pond presently has a relatively low nitrogen load from its watershed, due to its moderately sized watershed and proportionally large undeveloped areas, it is still significantly impaired by nitrogen enrichment and is clearly eutrophic (e.g. Head of Hummock). This apparent paradox results from its very low tidal exchange rate, resulting from barrier beach processes closing the inlet to the Atlantic Ocean on an annual basis. The highly restricted "flushing" of pond waters per annum serves to greatly increase the nitrogen sensitivity of this system, such that even low rates of nitrogen loading cause eutrophic conditions. The difficulty in achieving adequate tidal exchange during any given opening attempt has resulted in the present ecological impairment of the Hummock Pond System. The low rate of nitrogen removal through tidal flushing results in high nitrogen levels, large phytoplankton blooms and periodic anoxia of bottom waters. As such, the Town of Nantucket and work groups have long ago recognized that a rigorous scientific approach yielding site-specific nitrogen loading targets was required for decision-making, alternatives analysis and ultimately, habitat restoration. The completion of this multi-step process has taken place under the programmatic umbrella of the Massachusetts Estuaries Project, which is a partnership effort between all MEP collaborators and the Town. The modeling tools developed as part of this program provide the quantitative information necessary for the Towns’ nutrient management groups to predict the impacts on water quality from a variety of proposed management scenarios. Nitrogen Loading Thresholds and Watershed Nitrogen Management: Realizing the need for scientifically defensible management tools has resulted in a focus on determining the aquatic system’s assimilative capacity for nitrogen. The highest-level approach is to directly link the watershed nitrogen inputs with embayment hydrodynamics to produce water quality results that can be validated by water quality monitoring programs. This approach when linked to state- of-the-art habitat assessments yields accurate determination of the “allowable N concentration Executive Summary 3 increase” or “threshold nitrogen concentration”. These determined nitrogen concentrations are then directly relatable to the watershed nitrogen loading, which also accounts for the spatial distribution of the nitrogen sources, not just the total load. As such, changes in nitrogen load from differing parts of the embayment watershed can be evaluated relative to the degree to which those load changes drive embayment water column nitrogen concentrations toward the “threshold” for the embayment system. To increase certainty, the “Linked” Model is independently calibrated and validated for each embayment. Massachusetts Estuaries Project Approach: The Massachusetts Department of Environmental Protection (DEP), the University of Massachusetts – Dartmouth School of Marine Science and Technology (SMAST), and others including the Cape Cod Commission (CCC) have undertaken the task of providing a quantitative tool to communities throughout southeastern Massachusetts and the Islands (the Linked Watershed-Embayment Management Model) for nutrient management in their coastal embayment systems. Ultimately, use of the Linked Watershed-Embayment Management Model tool by municipalities in the region results in effective screening of nitrogen reduction approaches and eventual restoration and protection of valuable coastal resources. The MEP provides technical guidance in support of policies on nitrogen loading to embayments, wastewater management decisions, and establishment of nitrogen Total Maximum Daily Loads (TMDLs). A TMDL represents the greatest amount of a pollutant that a waterbody can accept and still meet water quality standards for protecting public health and maintaining the designated beneficial uses of those waters for drinking, swimming, recreation and fishing. The MEP modeling approach assesses available options for meeting selected nitrogen goals that are protective of embayment health and achieve water quality standards. The core of the Massachusetts Estuaries Project analytical method is the Linked Watershed-Embayment Management Modeling Approach, which links watershed inputs with embayment circulation and nitrogen characteristics. The Linked Model builds on well-accepted basic watershed nitrogen loading approaches such as those used in the Buzzards Bay Project, the CCC models, and other relevant models. However, the Linked Model differs from other nitrogen management models in that it:  requires site-specific measurements within each watershed and embayment;  uses realistic “best-estimates” of nitrogen loads from each land-use (as opposed to loads with built-in “safety factors” like Title 5 design loads);  spatially distributes the watershed nitrogen loading to the embayment;  accounts for nitrogen attenuation during transport to the embayment;  includes a 2D or 3D embayment circulation model depending on embayment structure;  accounts for basin structure, tidal variations, and dispersion within the embayment;  includes nitrogen regenerated within the embayment;  is validated by both independent hydrodynamic, nitrogen concentration, and ecological data;  is calibrated and validated with field data prior to generation of “what if” scenarios. The Linked Model Approach’s greatest assets are its ability to be clearly calibrated and validated, and its utility as a management tool for testing “what if” scenarios for evaluating watershed nitrogen management options. Executive Summary 4 For a comprehensive description of the Linked Model, please refer to the Full Report: Nitrogen Modeling to Support Watershed Management: Comparison of Approaches and Sensitivity Analysis, available for download at http://www.state.ma.us/dep/smerp/smerp.htm. A more basic discussion of the Linked Model is also provided in Appendix F of the Massachusetts Estuaries Project Embayment Restoration Guidance for Implementation Strategies, available for download at http://www.state.ma.us/dep/smerp/smerp.htm. The Linked Model suggests which management solutions will adequately protect or restore embayment water quality by enabling towns to test specific management scenarios and weigh the resulting water quality impact against the cost of that approach. In addition to the management scenarios modeled for this report, the Linked Model can be used to evaluate additional management scenarios and may be updated to reflect future changes in land-use within an embayment watershed or changing embayment characteristics. In addition, since the Model uses a holistic approach (the entire watershed, embayment and tidal source waters), it can be used to evaluate all projects as they relate directly or indirectly to water quality conditions within its geographic boundaries. Unlike many approaches, the Linked Model accounts for nutrient sources, attenuation, and recycling and variations in tidal hydrodynamics and accommodates the spatial distribution of these processes. For an overview of several management scenarios that may be employed to restore embayment water quality, see Massachusetts Estuaries Project Embayment Restoration Guidance for Implementation Strategies, available for download at http://www.state.ma.us/dep/smerp/smerp.htm. Application of MEP Approach: The Linked Model was applied to the Hummock Pond embayment system by using site-specific data collected by the MEP and water quality data from the Water Quality Monitoring Program conducted by the Nantucket Marine Department, with technical guidance from the Coastal Systems Program at SMAST (see Section II). Evaluation of upland nitrogen loading was conducted by the MEP. Estuaries Project staff obtained digital parcel and tax assessors data from the Town of Nantucket Geographic Information Systems Department, watershed specific water use data from the Wannacomet Water Company (WWC) and watershed boundaries adopted by the town as the Harbor Watershed Protection District (http://www.nantucket-ma.gov). During the development of the Nantucket Water Resources Management Plan, an island-wide groundwater mapping project, using many of the USGS wells on the Island, was completed to characterize the water table configuration of Nantucket (Horsley, Witten, Hegeman, 1990). MEP staff compared the Hummock Pond watershed that was approved as part of the Nantucket Water Resources Management Plan (HWH, 1990) to available information on the configuration of Hummock Pond, including the now “permanent” separation of Hummock Pond and Clark Cove into two systems, the location of the barrier beach, the wetlands in the area, water level measurements in Hummock Pond and HWH (1990) regional water table mapping. Review of the most current (1977) USGS quadrangle of the area shows Hummock Pond and Clark Cove joined near their southern ends and in the vicinity of the barrier beach. However, recent aerial photographs show that Hummock Pond and Clark Cove have been separate systems since at least March 1995 (Google Earth). Indicating that overwash from storms between 20 and 40 years B.P. filled the channel and have built a barrier to flow that will not easily be removed. Based on the review of aerial photographs, MEP staff modified the 1990 combined Hummock Pond/Clark Cove watershed to delineate a watershed to only Hummock Pond. Estuary watershed delineations completed in areas with relatively transmissive sand and gravel deposits, like most of Cape Cod and the Islands, have shown that watershed boundaries are usually better defined by elevation of the groundwater and its direction of flow, rather than by land surface topography (Cambareri and Eichner 1998, Millham and Howes 1994a,b). This approach was used by Horsley, Witten and Hegeman, Inc. (HWH) to complete the watershed Executive Summary 5 delineations for Nantucket including Hummock Pond (Section III); this watershed delineation was been largely confirmed by subsequent water table characterizations (e.g., Lurbano, 2001, Gardner and Vogel, 2005). MEP staff compared the HWH Harbor watershed to a more current aerial base maps (1995 - 2012). This comparison found some slight discrepancies likely based on a better characterization of the shoreline; changes were made based on best professional judgment and watershed/water table characterization experience in similar geologic settings The land-use data obtained from the Town was used to determine watershed nitrogen loads within the Hummock Pond embayment system (current and build-out loads are summarized in Section IV). Water quality within an embayment is the integration of nitrogen loads with the site-specific estuarine circulation. Therefore, water quality modeling of this estuarine system, which is periodically open to tidal forcing, included a thorough evaluation of the hydrodynamics of the estuarine system. Estuarine hydrodynamics control a variety of coastal processes including tidal flushing, pollutant dispersion, tidal currents, sedimentation, erosion, and water levels. Once the hydrodynamics of the system was quantified, transport of nitrogen was evaluated from tidal current information (during breach events) developed by the numerical models. A two-dimensional depth-averaged hydrodynamic model based upon the tidal currents during breach events and water elevations was employed for the Hummock Pond embayment system. Once the hydrodynamic properties of the estuarine system were computed, two- dimensional water quality model simulations were used to predict the dispersion of the nitrogen at current loading rates. Using standard dispersion relationships for estuarine systems of this type, the water quality model and the hydrodynamic model was then integrated in order to generate estimates regarding the spread of total nitrogen from the site-specific hydrodynamic properties. The distributions of nitrogen loads from watershed sources were determined from land-use analysis. Boundary nutrient concentrations in Atlantic Ocean source waters were taken from water quality monitoring data. Measurements of current salinity distributions throughout the estuarine waters of the Hummock Pond embayment system was used to calibrate the water quality model, with validation using measured nitrogen concentrations (under existing loading conditions). The underlying hydrodynamic model was calibrated and validated independently using water elevations measured in time series throughout the embayments. MEP Nitrogen Thresholds Analysis: The threshold nitrogen level for an embayment represents the average water column concentration of nitrogen that will support the habitat quality being sought. The water column nitrogen level is ultimately controlled by the watershed nitrogen load and the nitrogen concentration in the inflowing tidal waters during breach events (boundary condition). The water column nitrogen concentration is modified by the extent of sediment regeneration. Threshold nitrogen levels for the embayment systems in this study were developed to restore or maintain SA waters or high habitat quality. High habitat quality was defined as supportive of infaunal communities. Dissolved oxygen and chlorophyll a were also considered in the assessment. After developing the dispersion-mass balance model of Hummock Pond to simulate conditions that exist as a result of present management practices, the model was used to simulate a modified management approach that could be followed to improve water quality conditions in the pond year-round. The habitat quality in Hummock Pond has been historically moderate to poor, depending on the intensity of management, specifically the frequency and duration of openings to the ocean. To that effect, with a goal of seeking further improvements in water quality conditions in the Pond, an alternate management scheme was modeled using the dispersion-mass balance model developed for Hummock Pond. One goal of this proposed Executive Summary 6 management scenario is to convert the Head of Hummock into a freshwater pond year round in order to better manage water quality in the Head of Hummock Pond and also improve its function as a natural attenuator of nitrogen. Another goal is to reduce TN concentrations in the main body of Hummock Pond during the summer months, when benthic regeneration and algae production is greatest. A simple way to achieve these goals is to reduce load to the pond while also modifying the breaching schedule of the pond each year (Section V and VI). The Massachusetts Estuaries Project’s thresholds analysis, as presented in this technical report, provides the site-specific nitrogen reduction guidelines for nitrogen management of the Hummock Pond embayment system in the Town of Nantucket. Future water quality modeling scenarios should be run which incorporate the spectrum of strategies that result in nitrogen loading reduction to the embayment. For the current analysis, the MEP modeling team has initially focused upon modifying the breaching schedule for the Pond as a means of reaching a threshold water column nitrogen concentration supportive of infauna. 2. Problem Assessment (Current Conditions) A habitat assessment was conducted throughout the Hummock Pond system based upon available water quality monitoring data, distribution of macroalgae, time-series water column oxygen measurements, and benthic community structure. At present, eelgrass is not found within Hummock Pond. The current lack of eelgrass beds is expected given the high chlorophyll a and low dissolved oxygen levels as well as water column nitrogen concentrations within this system. In addition, it does not appear that eelgrass beds have been present in this system at any time over the past century, due to the systems only periodic tidal exchange and "naturally" nitrogen enriched condition. Therefore, habitat restoration in this eutrophic system should focus on infaunal habitat quality. The effect of nitrogen enrichment and extremely limited tidal flushing as is the case in Hummock Pond is to cause oxygen depletion; however, with increased phytoplankton (or epibenthic algae) production, oxygen levels will rise in daylight to above atmospheric equilibration levels in shallow systems (generally ~7-8 mg L-1 at the mooring sites). The dissolved oxygen records indicate that the Hummock Pond system is currently under seasonal oxygen stress, consistent with its significant nitrogen enrichment. The oxygen records obtained from Hummock Pond show that the lower main basin of the system has moderate daily oxygen excursions, indicative of moderate nitrogen enrichment which gradually increases moving towards Head of Hummock. The evidence of oxygen levels slightly above atmospheric equilibration indicates that the main basin of the system is moderately nitrogen enriched whereas oxygen levels well above atmospheric equilibration in the Head of Hummock indicates this portion of the system is highly nitrogen enriched. However, in general in the lower portion of the main basin, the daily excursions reach upper concentrations approximating atmospheric equilibrium with a moderate number of significantly higher excursions, consistent with moderate nitrogen enrichment. Note that high levels of nitrogen enrichment can result in phytoplankton blooms that generate D.O. levels routinely in the 10-12 mg L-1 range or higher at mid-day as observed in the Head of Hummock. At present, eelgrass is not found within Hummock Pond. The current lack of eelgrass beds is expected given the high chlorophyll a and low dissolved oxygen levels as well as water column nitrogen concentrations within this system. In addition, it does not appear that eelgrass beds have been present in this system at any time over the past century, due to the systems Executive Summary 7 only periodic tidal exchange and "naturally" nitrogen enriched condition. Therefore, habitat restoration in this eutrophic system should focus on infaunal habitat quality. Hummock Pond is presently supporting significantly to moderately degraded benthic infauna habitat quality. Hummock Pond is supporting a gradient in impairment from significantly impaired in the upper basin to moderately impaired in the lowest reach near the barrier beach. However, the tributary basin of Head of Hummock is currently supporting severely degraded habitat with no marine invertebrates and only 2 species of insect larvae. Head of Hummock contains lower salinity water than the Hummock Pond main basin, likely due to its function as a drown kettle pond in the uppermost reach of the system. As such, Head of Hummock is the focus of groundwater discharge from the watershed and as the entire system is usually without tidal currents, mixing is limited. The salinity of Head of Hummock is low enough (<5 ppt) to influence the plant and animal species present, although estuarine benthic animal communities are fully capable of colonizing at salinities to 3 ppt. However, the Head of Hummock basin is virtually devoid of benthic animals, only supporting 2 insect larval species and no estuarine infauna. In contrast, the main basin of Hummock Pond, does currently support benthic animal communities, even in the same salinity range as Head of Hummock. Therefore, the loss of benthic animals in Head of Hummock appears to be related to the high organic matter loading and periodic anoxia, rather than the low salinity (as was also observed in Oyster Pond, Falmouth). 3. Conclusions of the Analysis The threshold nitrogen level for an embayment represents the average watercolumn concentration of nitrogen that will support the habitat quality being sought. The watercolumn nitrogen level is ultimately controlled by the integration of the watershed nitrogen load, the nitrogen concentration in the inflowing tidal waters (boundary condition) and dilution and flushing via tidal flows during breach events. The water column nitrogen concentration is modified by the extent of sediment regeneration and by direct atmospheric deposition. Threshold nitrogen levels for this embayment system were developed to restore or maintain SA waters or high habitat quality. In this system, high habitat quality was defined as supportive of diverse benthic animal communities. Dissolved oxygen and chlorophyll a were also considered in the assessment. Watershed nitrogen loads (Tables ES-1 and ES-2) for the Town of Nantucket, Hummock Pond embayment system was comprised primarily of runoff from natural surfaces, load directly to the waterbody surface, nitrogen from farm animals and wastewater nitrogen. Land-use and wastewater analysis found that generally about 81% of the controllable watershed nitrogen load to the embayment was from wastewater and 6 percent was from farm animals in the watershed. A major finding of the MEP clearly indicates that a single total nitrogen threshold can not be applied to Massachusetts’ estuaries, based upon the results of the Nantucket Harbor analysis as well as that completed for Sesachacha Pond, Madaket Harbor and Long Pond, in addition to analyses conducted across Martha's Vineyard and Cape Cod (e.g. Great, Green and Bournes Pond Systems, Popponesset Bay System, the Hamblin / Jehu Pond / Quashnet River analysis in eastern Waquoit Bay, the analysis of the adjacent Rushy Marsh system and the Pleasant Bay and Nantucket Sound embayments associated with the Town of Chatham). Executive Summary 8 The threshold nitrogen level for the Hummock Pond embayment system in Nantucket was determined as follows: Hummock Pond Threshold Nitrogen Concentrations  With a goal of seeking further improvements in water quality conditions in the Pond, an alternate management scheme was modeled using the dispersion-mass balance model developed for Hummock Pond. One goal of this proposed management scenario is to maintain the Head of Hummock Pond as a freshwater feature year round. Another goal is to reduce TN concentrations in the main basin of Hummock Pond during the summer months, when benthic regeneration and algae production is greatest. Both of these goals are related, as better flushing management results in both higher salinities and lower nitrogen levels in pond waters. A simple way to achieve these goals is to add an additional mid-summer breach event each year.  A significant improvement in the nitrogen related health of Hummock Pond infaunal animal habitat would result from the modeled addition of a mid summer opening. It would be possible to use the monthly monitoring data to indicate when the mid-summer breach should occur. Total nitrogen levels within the upper basin (Head of Hummock) >1.0 mg N L-1 is a level associated with impoverished and degraded benthic animal habitat in other southeastern Massachusetts estuaries. Benthic communities have been found to be impaired at TN levels lower than found in Hummock Pond, e.g. Falmouth Inner Harbor, 0.58 mg TN L-1, Fiddlers Cove and Rands Harbor, 0.56 mg TN L-1 and 0.57 mg TN L-1, respectively. It appears that Hummock Pond (particularly the Head of Hummock Pond) is well beyond its threshold TN level to support healthy benthic habitat. As there is no evidence of present or historic eelgrass beds within the Hummock Pond Estuary, management actions should focus on restoration of benthic animal habitat.  A sentinel station was established for the Hummock Pond Estuary for development of a nitrogen threshold target that when met will restore benthic animal habitat throughout its estuarine reach. Since there is a relatively small gradient in nitrogen in the main basin, the sentinel station was selected at the basin’s mid-point, which reflects the average conditions within Hummock Pond. The sentinel station for Head of Hummock was established at the long-term monitoring station 3 (HUM-3). The average total nitrogen levels at the sentinel station are currently 0.72 mg N L-1. It should be noted that the freshening of Head of Hummock must be managed as part of restoration of benthic animal habitat in this estuary. This TN level is comparable to other estuarine basins throughout the region that show similar levels of oxygen depletion, organic enrichment and moderately impaired benthic animal habitat. TN levels >0.70 mg N L-1 are generally characterized as having significantly impaired benthic habitat, phytoplankton blooms and periodic hypoxia and even fish kills (e.g. finger ponds in Falmouth). Given that in numerous estuaries it has been previously and empirically determined that 0.500 mg TN L-1 is the upper limit to sustain unimpaired benthic animal habitat (Eel Pond, Parkers River, upper Bass River, upper Great Pond, upper Three Bays, as well as the 7 inner basins of Pleasant Bay) this level is deemed most appropriate for restoration of benthic animal habitat within Hummock Pond.  It should be noted that the above mentioned management scenarios oriented around altering the timing of breaches of the barrier beach, effective as these may be, are contingent on the ability of the Town of Nantucket to obtain necessary permitting of such Executive Summary 9 actions. Breaching of the barrier beach is necessarily subject to compliance with applicable federal, state and local statutes and regulations. It is important to note that the analysis of future nitrogen loading to the Hummock Pond estuarine system focuses upon additional shifts in land-use from forest/grasslands to residential and commercial development. However, the MEP analysis indicates that increases in nitrogen loading can occur under present land-uses, due to shifts in occupancy, shifts from seasonal to year-round usage and increasing use of fertilizers. In the case of the Hummock Pond watershed, these potential increases are likely to be slight. Nevertheless, given the highly over-loaded state of the system, watershed-estuarine nitrogen management should consider management approaches to prevent increased nitrogen loading from both shifts in land-uses (new sources) and from loading increases of current land-uses. The overarching conclusion of the MEP analysis of the Hummock Pond estuarine system is that restoration will necessitate a modified breaching schedule for the pond in order to enhance flushing with low nutrient, clean Atlantic Ocean waters. Reduction in the present nitrogen inputs and management options to negate additional future nitrogen inputs should also be considered in the context of additional breaching. Executive Summary 10 Table ES-1. Existing total and sub-embayment nitrogen loads to the estuarine waters of the Hummock Pond estuary system, observed nitrogen concentrations, and sentinel system threshold nitrogen concentrations. Sub-embayments Natural Background Watershed Load 1 (kg/day) Present Land Use Load 2 (kg/day) Present Septic System Load (kg/day) Present WWTF Load 3 (kg/day) Present Watershed Load 4 (kg/day) Direct Atmospheric Deposition 5 (kg/day) Present Net Benthic Flux (kg/day) Present Total Load 6 (kg/day) Observed TN Conc. 7 (mg/L) Threshold TN Conc. (mg/L) Hummock Pond 0.693 2.759 8.436 -- 11.195 1.918 0.196 13.309 0.65-0.99 0.50 Head of Hummock 0.137 0.315 1.366 -- 1.682 0.208 1.321 3.211 1.63 -- Combined Total 0.830 3.074 9.801 -- 12.877 2.126 1.517 16.520 0.65-1.63 0.508 1 assumes entire watershed is forested (i.e., no anthropogenic sources) 2 composed of non-wastewater loads, e.g. fertilizer and runoff and natural surfaces and atmospheric deposition to lakes 3 existing wastewater treatment facility discharges to groundwater 4 composed of combined natural background, fertilizer, runoff, and septic system loadings 5 atmospheric deposition to embayment surface only 6 composed of natural background, fertilizer, runoff, septic system atmospheric deposition and benthic flux loadings 7 average of 2011 and 2012 data, ranges show the upper to lower regions (highest-lowest) of the sub-embayment. Individual yearly means and standard deviations in Table VI-1. 8 Average concentration through summer months at water quality monitoring station HUM-3, achieved by load reduction and successful breaching of the inlet in late spring and mid-summer. Executive Summary 11 Table ES-2. Present Watershed Loads, Thresholds Loads, and the percent reductions necessary to achieve the Thresholds Loads for the Hummock Pond estuarine system on Nantucket Island. Sub-embayments Present Watershed Load 1 (kg/day) Target Threshold Watershed Load 2 (kg/day) Direct Atmospheric Deposition (kg/day) Benthic Flux Net 3 (kg/day) TMDL 4 (kg/day) Percent watershed reductions needed to achieve threshold load levels Hummock Pond 11.195 4.446 1.918 0.109 6.473 -60.3% Head of Hummock 1.682 0.383 0.208 0.473 1.064 -77.2% Combined Total 12.877 4.829 2.126 0.582 7.537 -62.5% (1) Composed of combined natural background, fertilizer, runoff, and septic system loadings. (2) Target threshold watershed load is the load from the watershed needed to meet the embayment threshold concentration identified in Table ES-1. (3) Projected future flux (present rates reduced approximately proportional to watershed load reductions). (4) Sum of target threshold watershed load, atmospheric deposition load, and benthic flux load. ACKNOWLEDGMENTS The Massachusetts Estuaries Project Technical Team would like to acknowledge the contributions of the many individuals who have worked tirelessly for the restoration and protection of the critical coastal resources of the Hummock Pond System. Without the long term efforts of these stewards, this project and other efforts to manage and restore this estuary would not be possible. First and foremost is the significant time and effort in data collection and discussion spent by members of the Town of Nantucket Water Quality Monitoring Program conducted by the Town of Nantucket Marine Department with technical, analytical and field support from the Coastal Systems Analytical Facility at SMAST. Of particular note are Dave Fronzuto and past Coordinators, Tracey Sundell and Keith Conant and currently Ms. Tara Riley. These individuals gave of their time to collect nutrient samples from this system over many years and without this information, the present analysis would not have been possible. Similarly, we would like to thank the Hummock Pond Association for its care and concern for the pond and for providing critical information on historic surveys of aquatic vegetation. A special thank you is extended to the Board of Selectmen, Libby Gibson (Town Manager), Kara Buzanoski (Town of Nantucket, Director, Department of Public Works) and Richard Ray of the Town of Nantucket Health Department for all the assistance provided over the years thus making this report as site- specific as possible. In addition, over the years, the Town of Nantucket Shellfish and Marine Department has worked tirelessly with SMAST Coastal Systems Staff and engineers from Applied Coastal Research and Engineering towards the development of a restoration and management strategy for this system and systems island-wide. The Marine Department has also provided important support to the present MEP effort. The technical team would also like to specifically acknowledge the efforts of Cormac Collier of the Nantucket Land Council and Andrew Vorce, Director of the Nantucket Planning and Economic Development Commission for facilitating the land use analysis effort within the MEP. We would also like to thank Rosemary Blacquier (Woodard and Curran), who has been instrumental to getting this analysis funded and who has facilitated obtaining historical data sets that nobody else seemed capable of finding as well as Dr. Sarah Oktay from the University of Massachusetts-Boston, Nantucket Field Station. In addition to numerous local contributions, technical, policy and regulatory support has been freely and graciously provided by MaryJo Feurbach and Art Clark of the USEPA; and our MassDEP colleagues: Rick Dunn, Dave DeLorenzo, Geri Lambert and Brian Dudley. We are also thankful for the long hours in the field and laboratory spent by the technical staff (Jennifer Benson, Michael Bartlett, Sara Sampieri and Dahlia Medieros), interns and students within the Coastal Systems Program at SMAST-UMD both to support the water quality monitoring program and the assessment of the estuarine resources of Hummock Pond. Support for this project was provided entirely by the Town of Nantucket and its taxpayers as well as generous patrons of Hummock Pond, specifically Bob Williams, President of and representative for individuals of the Hummock Pond Association in addition to Cormac Collier and the Nantucket Land Council. PROPER CITATION Howes B.L., S. Kelley, , E.M. Eichner, R.I. Samimy, D.R. Schlezinger J. Ramsey (2013). Linked Watershed-Embayment Model to Determine the Critical Nitrogen Loading Threshold for Hummock Pond, Massachusetts. SMAST/DEP Massachusetts Estuaries Project, Massachusetts Department of Environmental Protection. Boston, MA. © [2013] University of Massachusetts & Massachusetts All Rights Reserved No permission required for non-commercial use i Table of Contents I. INTRODUCTION ...................................................................................................................... 1  I.1 THE MASSACHUSETTS ESTUARIES PROJECT APPROACH ........................................ 5  I.2 NUTRIENT LOADING ......................................................................................................... 8   I.3 WATER QUALITY MODELING ......................................................................................... 10  I.4 REPORT DESCRIPTION .................................................................................................. 11  II. PREVIOUS STUDIES RELATED TO NITROGEN MANAGEMENT ..................................... 13  III. DELINEATION OF WATERSHEDS ..................................................................................... 24  III.1 BACKGROUND ............................................................................................................... 24  III.2 HUMMOCK POND CONTRIBUTORY AREAS ............................................................... 24  IV. WATERSHED NITROGEN LOADING TO EMBAYMENT: LAND USE, STREAM INPUTS, AND SEDIMENT NITROGEN RECYCLING .................................................... 31  IV.1 WATERSHED LAND USE BASED NITROGEN LOADING ANALYSIS ......................... 31  IV.1.1 Land Use and Water Use Database Preparation ..................................................... 32  IV.1.2 Nitrogen Loading Input Factors ................................................................................ 34  IV.1.3 Calculating Nitrogen Loads ...................................................................................... 39  IV.2 ATTENUATION OF NITROGEN IN SURFACE WATER TRANSPORT ......................... 45  IV.2.1 Background and Purpose ......................................................................................... 45  IV.3 BENTHIC REGENERATION OF NITROGEN IN BOTTOM SEDIMENTS ...................... 47  IV.3.1 Sediment-Watercolumn Exchange of Nitrogen ........................................................ 47  IV.3.2 Method for determining sediment-water column nitrogen exchange ........................ 48  IV.3.3 Rates of Summer Nitrogen Regeneration from Sediments ...................................... 50  Hummock Pond ................................................................................................................... 53  V. HYDRODYNAMIC MODELING ............................................................................................ 54  V.1 INTRODUCTION.............................................................................................................. 54  V.1.1 System Physical Setting ............................................................................................ 55  V.1.2 System Hydrodynamic Setting ................................................................................... 55  V.1.3 Pond Management Practices ..................................................................................... 56  V.2 HYDRODYNAMIC FIELD DATA COLLECTION AND ANALYSIS ................................... 56  V.2.1. Bathymetry ................................................................................................................ 56  V.2.2 Tide Data ................................................................................................................... 57  V.3 HYDRODYNAMIC MODEL DEVELOPMENT .................................................................. 62  V.3.1 Modeling flow through a breach ................................................................................ 63  V.3.2 RMA-2 Model Theory ................................................................................................ 64  V.3.3 Model Setup .............................................................................................................. 65  V.3.3.1 Grid generation ................................................................................................... 65  V.3.3.2 Boundary condition specification ........................................................................ 67  V.3.3.3 Calibration ........................................................................................................... 67  ii V.3.4 Flushing Characteristics ............................................................................................ 70  VI. WATER QUALITY MODELING ............................................................................................ 74  VI.1 DATA SOURCES FOR THE MODEL ............................................................................. 74  VI.1.1 Hydrodynamics and Tidal Flushing in the Embayments .......................................... 74  VI.1.2 Nitrogen Loading to the Embayments ...................................................................... 75  VI.1.3 Measured Nitrogen Concentrations in the Embayments .......................................... 75  VI.2 MODEL DESCRIPTION AND APPLICATION ................................................................ 75  VI.2.1 Model Formulation..................................................................................................... 77  VI.2.2 Boundary Condition Specification ............................................................................ 78  VI.2.3 Development of Present Conditions Model ............................................................. 78  VI.2.4 Total Nitrogen Model Development .......................................................................... 80  VI.2.5 Build-Out and No Anthropogenic Load Scenarios .................................................... 84  VI.2.5.1 Build-Out ............................................................................................................ 84  VI.2.5.2 No Anthropogenic Load ..................................................................................... 85  VII. ASSESSMENT OF EMBAYMENT NUTRIENT RELATED ECOLOGICAL HEALTH ........ 87  VII.1 OVERVIEW OF BIOLOGICAL HEALTH INDICATORS ................................................. 87  VII.2 BOTTOM WATER DISSOLVED OXYGEN .................................................................... 88  VII.3 EELGRASS DISTRIBUTION - TEMPORAL ANALYSIS ................................................ 99  VII.4 BENTHIC INFAUNA ANALYSIS .................................................................................. 102  VIII. CRITICAL NUTRIENT THRESHOLD DETERMINATION AND DEVELOPMENT OF WATER QUALITY TARGETS ...................................................................................... 108  VIII.1. ASSESSMENT OF NITROGEN RELATED HABITAT QUALITY .............................. 108  VIII.2 THRESHOLD NITROGEN CONCENTRATIONS ....................................................... 111  VIII.3 DEVELOPMENT OF TARGET NITROGEN LOADS .................................................. 113  IX.1 FRESH WATER HEAD OF HUMMOCK....................................................................... 116  IX.2 FRESH WATER HEAD OF HUMMOCK THRESHOLD N LOADING ........................... 117  X. REFERENCES ..................................................................................................................... 119  iii List of Figures Figure I-1. Location of the Hummock Pond system, Island of Nantucket, Town of Nantucket, Massachusetts. Hummock Pond is a significant coastal salt pond, maintained by periodic breaching of the barrier beach to allow exchange with Atlantic Ocean waters.................................................................... 1  Figure I-2. Study region for the Massachusetts Estuaries Project analysis of the Hummock Pond Embayment System. Tidal waters enter the Pond through periodic breaching of the barrier beach and flow in from the Atlantic Ocean. Freshwaters enter from the watershed primarily through direct groundwater discharge. .............................................................................................................. 3  Figure I-3. Massachusetts Estuaries Project Critical Nutrient Threshold Analytical Approach ............................................................................................................... 9  Figure II-1a. Town of Nantucket Water Quality Monitoring Program. Hummock Pond Estuarine water quality monitoring stations sampled by the Nantucket Marine Department (2002-2007). ........................................................................ 15  Figure II-1b. Town of Nantucket Island-wide Water Quality Monitoring Program: Hummock Pond Estuarine water quality monitoring stations sampled by the Nantucket Marine and Coastal Resources Department (2010 and 2012). .................................................................................................................. 16  Figure II-2. Location of shellfish growing areas and their status relative to shellfish harvesting as determined by Mass Division of Marine Fisheries. Closures are generally related to bacterial contamination or "activities", such as the location of marinas. ............................................................................................. 21  Figure II-3. Estimated Habitats for Rare Wildlife and State Protected Rare Species within the Hummock Pond Estuary as determined by the Massachusetts Natural Heritage and Endangered Species Program (NHESP). ......................... 22  Figure II-4.  Anadromous fish run within the Hummock Pond Estuary as determined by Mass Division of Marine Fisheries. The red diamond shows area where fish were observed. ............................................................................................. 23  Figure III-1.  Watershed and sub-watershed delineations for the Hummock Pond estuary system. This MEP delineation is based an updated review of HWH (1990) and Town of Nantucket Watershed Protection District delineation, which has a watershed that includes both Hummock Pond and Clark Cove. MEP adjusted the watershed to include only Hummock pond and confirmed the delineation based on measured water level in the pond, wetland delineations and comparison to similar systems in the region. ........................... 25  Figure III-2.  Comparison of HWH and MEP Watersheds. HWH (1990) watershed includes Clark Cove and a northeastern bulge that includes a wetland system. Review of aerial photos shows that the Cove and Pond have not been hydraulically connected since at least 1995. Review of the wetlands in the upper watershed area shows a nearly radial distribution of streams around its borders, which is consistent with the HWH water table map that showed the regional groundwater divide in this area. ......................................... 26  Figure III-3.  Water Elevations in Hummock Pond follow 2006 and 2012 openings. Data collected by Applied Coastal Research and Engineering and the SMAST Coastal Systems Program. Change in water levels reflects groundwater discharge into Hummock Pond. Comparison of this data with the estimated inflows from the MEP watershed delineation show good agreement and reinforce the reasonableness of the watershed delineation. ............................... 28  iv Figure IV-1. Land-use in the Hummock Pond watershed. The 3 sub-watersheds are delineated by the heavy blue line, the outer blue line encompasses the entire contributing area to the estuary. The watershed is completely contained within the Town of Nantucket. Parcels and land use classifications are based on 2012 assessor’s records provided by the town and county and are grouped into the generalized categories used by MADOR (2012). Parcels in the “900s” category are lands owned by the town or non-profit entities, such as land banks or churches. Parcels in the “unknown” category do not have land use classifications in the provided town assessor’s database. .................................................................................. 33  Figure IV-2.  Distribution of land-uses within the 3 subwatersheds and whole system watershed to Hummock Pond. Land use categories are generally based on town assessor’s land use classification and groupings recommended by MADOR (2012). Unclassified parcels do not have an assigned land use code in the town assessor’s databases. Only percentages greater than or equal to 4% are labeled. ...................................................................................... 35  Figure IV-3. Land use-specific unattenuated nitrogen load (by percent) to the overall Hummock Pond System watershed. “Overall Load” is the total nitrogen input within the watershed, while the “Local Control Load” represents those nitrogen sources that could potentially be under local regulatory control. ........... 42  Figure IV-4. Developable Parcels in the Hummock Pond watershed. Developable parcels were determined by reviewing minimum lot sizes specified under current town zoning. Initial MEP buildout results were reviewed with the town planner and modified. Parcels colored yellow are developed residential parcels with additional development potential based on existing zoning, while parcel colored green are undeveloped parcels classified as developable for residential land uses by the town assessor. Parcels colored purple do not have assigned land use codes in the town assessor’s database, but are classified as developable........................................................ 46  Figure IV-5. Hummock Pond embayment system sediment sampling sites (yellow symbols) for determination of nitrogen regeneration rates. Numbers are for reference to Table IV-3. ....................................................................................... 49  Figure IV-6. Conceptual diagram showing the seasonal variation in sediment N flux, with maximum positive flux (sediment output) occurring in the summer months, and maximum negative flux (sediment up-take) during the winter months. ................................................................................................................ 51  Figure V-1. Topographic map detail of Hummock Pond on the southern shore of Nantucket Island. ................................................................................................. 54  Figure V-2. Bathymetry survey lines (yellow) and tide locations (red) in Hummock Pond. ................................................................................................................... 58  Figure V-3. Observed water levels at the time of the autumn 2006 breach event. The blue line shows water levels in the pond, while tides recorded offshore of the pond are shown by the black line. ................................................................. 59  Figure V-4. Observed water levels at the time of the autumn 2012 breach event. The blue line shows water levels in the pond, the black line shows tides recorded at the Martha’s Vineyard Coastal Observatory. .................................... 59  Figure V-5. Example of an observed astronomical tide as the sum of its primary constituents. ........................................................................................................ 60  Figure V-6. Measured tide from the gauge station offshore of Hummock Pond, starting in October 2006, with the computed 22 components of astronomical tide v resulting from the harmonic analysis, and the resulting non-tidal residual water level. .......................................................................................................... 62  Figure V-7. A comparison of the broad-crested weir model results with the recorded pond elevations during a simulated breach of Hummock Pond that is open for one month. This simulation show the likely range of possible tides in the pond after a breaching. ................................................................................. 64  Figure V-8. Bathymetry data interpolated to the finite element mesh used with the RMA-2 hydrodynamic model. Contours represent the bottom elevation relative to North American Vertical Datum 1988. The primary data sources used to develop the grid mesh are the February 2012 surveys of the system. ................................................................................................................ 66  Figure V-9. Plot of hydrodynamic model grid mesh for Hummock Pond. Colors are used to designate the different model material types used to vary model calibration parameters and compute flushing rates. ............................................ 68  Figure V-10. Comparison of results calculated using the breach model (section V.4.1) and the hydrodynamic model of Hummock Pond. The R2 correlation between the two models for the time period shown in the plot is 0.89, with a RMS error of 0.07 feet. ........................................................................................ 70  Figure V-11. Time variation of computed flow rates for the modeled Hummock Pond breach. Model period shown corresponds to spring tide conditions, where the tide range is the largest, and resulting flow rates are correspondingly large compared to neap tide conditions. Positive flow indicated flooding tide flows into the Pond, while negative flow indicates ebbing tide flows discharging from the pond. .................................................................................. 71  Figure VI-1. USGS topographic map showing monitoring station locations in Hummock Pond that were designated by the Nantucket Marine Department. ..................... 76  Figure VI-2. Model salinity target values are plotted against measured data, together with the unity line, for the simulation period from June 27 through August 24, 2012. RMS error for this model verification run is 0.9 ppt. ........................... 80  Figure VI-3. Plot of salinity contours in Hummock Pond and Black Point Pond at the end of the modeled August 2006 calibration period. .................................................. 81  Figure VI-4. RMA-4 model output for Hummock Pond showing how pond salinities vary with the number of days open for a breached inlet. Model output is taken at monitoring station HUM-3. Model results also assume a fully open breach for the complete simulation period........................................................... 81  Figure VI-5. Model TN target values are plotted against measured concentrations, together with the unity line, for the simulation period from June 27 through August 24, 2012. RMS error for this model verification run is 0.058 mg/L and the R2 correlation coefficient is 0.71. ............................................................ 82  Figure VI-6. Plot of TN contours in Hummock Pond and Black Point Pond at the end of the modeled August 2006 calibration period. ...................................................... 83  Figure VI-7. RMA-4 model output for Hummock Pond showing how pond TN concentrations vary as a function of initial salinity concentration (here for 10, 15 and 20 ppt) and number of days open for the breach. Model output is taken at monitoring station HUM-3. Model results also assume a fully open breach for the complete simulation period. ................................................. 83  Figure VI-8. Modeled TN concentrations in the main basin of Hummock Pond (at monitoring stations HUM-3) after a simulated four-day open breach and its subsequent closure, with an initial concentration of 0.60 mg/L, for the build- out N loading scenario. ........................................................................................ 85  vi Figure VI-9. Modeled TN concentrations in the main basin of Hummock Pond (at monitoring stations HUM-3) after a simulated four-day open breach and its subsequent closure, with an initial concentration of 0.60 mg/L, for the no anthropogenic N loading scenario. ...................................................................... 86  Figure VII-1. Example of typical average water column respiration rates (micro- Molar/day) from water collected throughout the Popponesset Bay System, Cape Cod (Schlezinger and Howes, unpublished data). Rates vary ~7 fold from winter to summer as a result of variations in temperature and organic matter availability. ................................................................................................ 90  Figure VII-2. Aerial Photograph of the Hummock Pond embayment system in the Town of Nantucket showing the location of the continuously recording Dissolved Oxygen / Chlorophyll-a sensors deployed during the Summer of 2007.The gauge, “Hummock Pond Upper”, is located in Head of Hummock, while the 2 other gauges are located within the upper and lower reaches of the main basin of Hummock Pond. .................................................................................... 91  Figure VII-3. Bottom water record of dissolved oxygen in Head of Hummock (Hummock Pond upper station, Figure VII-2), Summer 2007. Calibration samples represented as red dots. ..................................................................................... 92  Figure VII-4. Bottom water record of Chlorophyll-a in the Hummock Pond upper station in Head of Hummock, Summer 2007. Calibration samples represented as red dots. .............................................................................................................. 93  Figure VII-5. Bottom water record of dissolved oxygen at the Hummock Pond middle gauge, Summer 2007. Calibration samples represented as red dots. ................ 93  Figure VII-6. Bottom water record of Chlorophyll-a in the Hummock Pond middle gauge, Summer 2007. Calibration samples represented as red dots. ............................ 94  Figure VII-7. Bottom water record of dissolved oxygen at the Hummock Pond lower station, Summer 2007. Calibration samples represented as red dots. ................ 94  Figure VII-8. Bottom water record of Chlorophyll-a in the Hummock Pond lower station, Summer 2007. Calibration samples represented as red dots. ............................ 95  Figure VII-9. Redhead Pondgrass, mixed Redhead Pondgrass and Sago Pondweed. ......... 100  Figure VII-10. Sago Pondweed. ............................................................................................... 100  Figure VII-11. Eel Grass. .......................................................................................................... 100  Figure VII-12. Coontail. ............................................................................................................ 101  Figure VII-13. Submerged aquatic vegetation survey of the Hummock Pond embayment system showing location of different types of aquatic vegetation observed in 2005 (courtesy of Hummock Pond Association - 2006 Weed Inventory Map). This map and associated data can be obtained by contacting Bob Williams, President HPA, rwilliams@npb.com or Toni Moores, “Chief Weed Watcher” HPA, tonimoores@comcast.net. ........................................................ 102  Figure VII-14. Submerged aquatic vegetation survey of the Hummock Pond embayment system showing location of different types of aquatic vegetation observed in 2006 (courtesy of Hummock Pond Association - 2006 Weed Inventory Map). This map and associated data can be obtained by contacting Bob Williams, President HPA, rwilliams@npb.com or Toni Moores, “Chief Weed Watcher” HPA, tonimoores@comcast.net. ........................................................ 103  Figure VII-15. Aerial photograph of the Hummock Pond embayment system showing location of benthic infaunal sampling stations (yellow symbols) within the main pond basin and Head of Hummock Pond. ................................................ 104  Figure VII-16. Location of shellfish growing areas and their status relative to shellfish harvesting as determined by Mass Division of Marine Fisheries. Closures vii are generally related to bacterial contamination or "activities", such as the location of marinas. ........................................................................................... 107  Figure VIII-1. Time series of modeled TN concentrations at monitoring station TGP 7 from the threshold model scenario where the pond is breached in late May for four days. ..................................................................................................... 115  Figure IX-1. Modeled TN concentrations in the main basin of Hummock Pond (at monitoring stations HUM-3) after a simulated four-day open breach and its subsequent closure, with an initial concentration of 0.60 mg/L, showing the N attenuation effect of changing Head of Hummock into a fresh water pond, with no other change in watershed loading. ............................................ 117  Figure IX-2. Modeled TN concentrations in the main basin of Hummock Pond (at monitoring stations HUM-3) after a simulated four-day open breach and its subsequent closure, with an initial concentration of 0.60 mg/L, for the alternate Threshold N loading scenario that includes the attenuation effect of turning Head of Hummock into a fresh water pond. ...................................... 118  viii List of Tables Table III-1. Daily groundwater discharge from each of the sub-watersheds to the Hummock Pond Estuary. ..................................................................................... 29  Table IV-1. Primary Nitrogen Loading Factors used in the Hummock Pond MEP analyses. General factors are from MEP modeling evaluation (Howes & Ramsey 2001). Site-specific factors are derived from watershed-specific data. .................................................................................................................... 40  Table IV-2. Hummock Pond Nitrogen Loads. Present nitrogen loads are based on current conditions. Buildout nitrogen loads are based on the additional development allowed under current zoning at minimum lot sizes. Factors used to determine nitrogen loads are discussed in the text. Attenuation assigned to Maxcy Pond is a standard MEP assumption based on data collected from other ponds within the same ecoregion. All values are kg N yr-1. ...................................................................................................................... 41  Table IV-3. Rates of net nitrogen return from sediments to the overlying waters of the Hummock Pond Basins. These values are combined with the basin areas to determine total nitrogen mass in the water quality model (see Chapter VI). Measurements represent July -August rates. N = number of sites .............. 53  Table V-1. Annual Hummock Pond openings between 1995 and 2007, Town Marine Department records. ............................................................................................ 56  Table V-2. Tide datums computed from 92-day records collected offshore Hummock Pond starting October 20, 2006. Datum elevations are given relative to the mean sea level reference of the area. ................................................................. 60  Table V-3. Tidal constituents computed for tide station offshore Hummock Pond using the record from October 2006 through January 2007. ........................................ 61  Table V-4. Percentages of Tidal versus Non-Tidal Energy using a 23 constituent analysis for the full tide record recorded offshore of Hummock Pond between October 20, 2006 and January 19, 2007. ............................................. 62  Table V-5. Manning’s Roughness and eddy viscosity coefficients used in simulations of Hummock Pond. These embayment delineations correspond to the material type areas shown in Figure V-10. .......................................................... 69  Table V-6.  Embayment mean volumes and average tidal prism for the Hummock Pond system. ................................................................................................................ 72  Table V-7. Computed System and Local residence times for the whole of the Hummock Pond estuarine system and for the Head of Hummock sub- embayment. ......................................................................................................... 73  Table VI-1. Measured nitrogen concentrations and salinities for Hummock Pond. “Data mean” values are calculated as the average of the separate yearly means. TN data represented in this table were collected in 2010 and 2012. The offshore Atlantic Ocean data (offshore Pleasant Bay Inlet) are from the summer of 2005. ................................................................................................. 75  Table VI-2. Present conditions sub-embayment and surface water loads used for total nitrogen modeling of Hummock Pond, with total watershed N loads, atmospheric N loads, and benthic flux. ............................................................... 78  Table VI-3. Values of longitudinal dispersion coefficient, E, used in calibrated RMA4 model runs of salinity and nitrogen concentration for the Hummock Pond estuary system. ................................................................................................... 79  Table VI-4. Comparison of sub-embayment watershed loads used for modeling of present (2003), present 2007, build-out, and no-anthropogenic (“no-load”) ix loading scenarios of Hummock Pond. These loads do not include direct atmospheric deposition (onto the sub-embayment surface) or benthic flux loading terms. ...................................................................................................... 84  Table VI-5. Build-out conditions sub-embayment and surface water loads used for total nitrogen modeling of Hummock Pond, with total watershed N loads, atmospheric N loads, and benthic flux. ............................................................... 84  Table VI-6. No Anthropogenic conditions sub-embayment and surface water loads used for total nitrogen modeling of Hummock Pond, with total watershed N loads, atmospheric N loads, and benthic flux. ..................................................... 85  Table VII-1. Days and percent of time during deployment of in situ sensors that bottom water oxygen levels were below various benchmark oxygen levels within the Hummock Pond (including Head of Hummock) Embayment System. .......... 97  Table VII-2. Duration (days and % of deployment time) that chlorophyll-a levels exceed various benchmark levels within the Hummock Pond (including Head of Hummock, “upper”) Estuary. “Mean” represents the average duration of each event over the benchmark level and “S.D.” its standard deviation. Data collected by the Coastal Systems Program, SMAST. ................................. 98  Table VII-3. Benthic infaunal community data for the Hummock Pond Embayment System (inclusive of Head of Hummock). Estimates of the number of species adjusted to the number of individuals and diversity (H’) and Evenness (E) of the community allow comparison between locations (Samples represent surface area of 0.0625 m2). Stations refer to map in Figure VII-15, Head of Hummock is fresher than Hummock Pond and was colonized by insect larvae (chironomidae, chaoboridae) not estuarine benthic animals. Note the clear gradient in habitat quality from the uppermost to lowermost regions. ...................................................................... 105  Table VIII-1. Summary of nutrient related habitat quality within the Hummock Pond Estuary, Town of Nantucket, MA, based upon assessments detailed in Section VII. Head of Hummock is a kettle pond opened via a channel to the upper main basin of Hummock Pond. Hummock Pond is periodically opened to tidal flows, but receives salt water in storm overwash of the barrier beach. .................................................................................................... 112  Table VIII-2. Comparison of sub-embayment septic loads used for modeling of present and modeled threshold loading scenarios of Hummock Pond. These loads do not include direct atmospheric deposition (onto the sub-embayment surface) or benthic flux loading terms................................................................ 114  Table VIII-3. Comparison of sub-embayment watershed loads used for modeling of present and modeled threshold loading scenarios of Hummock Pond. These loads do not include direct atmospheric deposition (onto the sub- embayment surface) or benthic flux loading terms. ........................................... 114  Table VIII-4. Sub-embayment and surface water loads used for total nitrogen modeling of threshold conditions for Hummock Pond, with total watershed N loads, atmospheric N loads, and benthic flux. ............................................................. 115  Table IX-1. Comparison of sub-embayment watershed loads used for modeling of present (2003), present 2007, build-out, and no-anthropogenic (“no-load”) loading scenarios of Hummock Pond. These loads do not include direct atmospheric deposition (onto the sub-embayment surface) or benthic flux loading terms. .................................................................................................... 118  Table IX-2. Build-out conditions sub-embayment and surface water loads used for total nitrogen modeling of Hummock Pond, with total watershed N loads, atmospheric N loads, and benthic flux. ............................................................. 118  University of Massachusetts Dartmouth School of Marine Science and Technology Coastal Systems Group 706 South Rodney French Blvd. New Bedford, MA 02744-1221 ************************Technical Memorandum **************************** To: David Fronzuto,Nantucket Marine Department Richard Ray, Nantucket Health Department From: Brian Howes, Director Coastal Systems Program Ed Eichner, Coastal Systems Program Roland Samimy, Coastal Systems Program John Ramsey, Applied Coastal Research & Engineering, Inc. RE: Scenarios 1, 2, 3, 4 of Nantucket Harbor MEP Linked Model Date: Original: August 23, 2011 Updated:January 4, 2012 ****************************************************************************** The present Technical Memorandum details the results of four (4) Scenario Runs completed using the MEP Linked Watershed-Embayment Model developed for the Nantucket Harbor System. Development of the model and establishment of the nitrogen thresholds for the Nantucket Harbor System are described in the MassDEP/SMAST MEP Nitrogen Threshold Report for the Nantucket Harbor Estuary1. These Scenarios are the initial planning runs for this system for the Town of Nantucket. The scenarios focus on nitrogen management strategies within the watershed (scenario 1 and 2), increasing tidal flushing (scenario 3 which elevates the jetties) and a combination of increasing tidal flushing and nitrogen management within the watershed (scenario 4 elevates the jetties and utilizes watershed loading developed for scenario 2). The effects of the watershed and flushing alterations on nitrogen levels throughout the waters of the Nantucket Harbor System are compared to the MEP target nitrogen levels (thresholds) needed to achieve restoration. The scenarios were developed by the Town of Nantucket in order to provide guidance to municipal officials, private citizens and environmental groups to support decisions regarding the nitrogen management planning and load allocation related to the stewardship of this critical coastal system. At present, historic eelgrass and benthic animal habitat within Nantucket Harbor is showing impairment in the Head of the Harbor and Polpis Harbor sub-basins, although most of the estuary is generally supporting high quality habitat. Impairment stems from nitrogen enrichment due to watershed nitrogen inputs that exceed this estuary's assimilative capacity under its present hydrodynamic regime. As part of nitrogen management planning, the Town of Nantucket is working with the MEP Technical Team (through SMAST)in the use of the MEP Linked Model developed for this estuary. 1 Howes, B.L., S.W. Kelley, J.S. Ramsey, R.I. Samimy, D.R. Schlezinger, E. Eichner. 2006. Linked Watershed- Embayment Modeling Approach to Determine Critical Nitrogen Loading Thresholds for Nantucket Harbor, Town of Nantucket, MA. Massachusetts Estuaries Project Final Report to Massachusetts Department of Environmental Protection, Boston MA. 168pp. The two sewering scenarios assume that wastewater is collected in two areas within the Harbor watershed and is then treated and discharged at the existing Town Waste Water Treatment Facility. The third modeling run (scenario 3)focuses on tidal flushing by elevating the main jetties at the Harbor inlet. The fourthmodeling run combines the wastewater loading reduction from scenario 2 with the tidal flushing alteration in scenario 3. Details of the scenarios are as follows: Scenario 1, Monomoy: The MEP Nantucket Harbor linked model was used to evaluate the extent of improvement in nitrogen related water quality that would be achieved by lowering nitrogen loading to the watershed from septic systems through the extension of sewer lines into the Monomoy area (Figure 1) and connecting all dwellings possible. This scenario is based on existing, not buildout, watershed nitrogen loading and model output was assessed relative to the MassDEP TMDL targets for Nantucket Harbor. Scenario 2, Monomoy / Shimmo: The MEP Nantucket Harbor linked model was used to evaluate the extent of improvement in nitrogen related water quality that would be achieved by lowering nitrogen loading to the watershed from septic systems through the extension of the sewer lines into both the Monomoy and Shimmo areas (see Figure 1) and connecting all dwellings possible. This scenario is based on existing, not buildout, watershed nitrogen loading and model output was assessed relative to the MassDEP TMDL targets for Nantucket Harbor. Scenario 3, Elevate jetties: The MEP Nantucket Harbor linked model was used to evaluate the extent of improvement in nitrogen related water quality that would be achieved by elevating the jetties to the main tidal inlet of the Harbor to at or above high tide (full tide jetty). This scenario is based on existing watershed nitrogen loading documented in the MEPthreshold reportand model output was assessed relative to the MassDEP TMDL targets for Nantucket Harbor. Scenario4, Monomoy / Shimmo + elevate jetties: The MEP Nantucket Harbor linked model was used to evaluate the extent of improvement in nitrogen related water quality that would be achieved by the combined actions of (a)lowering nitrogen loading to the watershed from septic systems through the extension of sewer lines into Monomoy and Shimmo areas (Scenario 2) plus (b) increased tidal flushing by elevating the jetties to the main tidal inlet of the Harbor to at or above high tide (full tide jetty; Scenario 3). This scenario is based on existing watershed nitrogen loading modification developed in Scenario 2 and model output was assessed relative to the MassDEP TMDLtargets for Nantucket Harbor. Scenario Results: As part of the development of the Monomoy and Shimmo sewering scenarios, MEP staff noted the following watershed/sewer district characteristics: 1. Monomoy seweringscenario (Scenario 1) has 181 new properties to be sewered, all are inthe Harbor subwatershed, some are also within the existing sewer district but not connected (see figure 1). 2. Monomoy/Shimmo scenario (Scenario 2) has 443 new properties to be sewered (including the properties in the Monomoysewering scenario above); 369 are in the Harbor subwatershed & 74 are in the Quaise subwatershed. 3. In the Monomoy scenario(Scenario 1) there are 1,014 properties that remain unsewered in the Town subwatershed, 716 of which are developed or developable. 4. Among the remaining 716 developed or developable properties in the Town subwatershed, 666 are in the existing town sewer district and have either a listing in the database we received from the town as using a septic system (262 parcels)2 or nolisting of wastewater treatment type (404 parcels). 5. Among the 404 properties within the existing sewer district that have no wastewater classification type, 106 of them have town assessor-assigned land use codes that would indicate that they are developed and would need a septic system or sewer connection. 6. Review of the town-supplied databases used in the MEP N loading model indicates that some of the properties with land use classifications that would not automatically mean they have a wastewatersystem have buildings on them. Adjusting the count with these properties, indicates that the number of potential septic systems inside the sewer district would be close to 400. 7. Connecting the ~400 properties already inside the existing town sewer district would have approximately the same watershed nitrogen loading reduction as the proposed combined sewering of Monomoy/Shimmo. The caveat to this is the need to confirm the listings in the Town database, which might be a useful next step if the Town opts to move in this directionat some time in the future. The effect of extending the sewer lines into the Monomoy area (Scenario 1) and the combined Monomoy and Shimmo area(Scenario 2) to remove nitrogen loads from existing on-site wastewater septic systems was to lower the watershed nitrogen load to the Nantucket Harbor Town basin (Scenario 1: Table 1) and Town and Quaise basins (Scenario 2: Table 2), respectively. No changes in the watershed nitrogen loads occurred in Scenario 3, only tidal flushing was effected (Table 3). Scenario 4 was the combination of the septic effluent removal in Monomoy and Shimmo (Scenario 2) plus the tidal flushing enhancement (Scenario 3). All scenarios resulted in lower nitrogen levels within the receiving waters of the Harbor (Table 4). The resulting nitrogen levels within the waters of Nantucket Harbor and its tributary basin, Polpis Harbor, were lower compared to present conditions in all scenarios, with resulting TN levels in: Scenario 1 > Scenario 2 > Scenario 3 > Scenario 4. Scenario 4, the combined effect of extending sewers to Monomoy and Shimmo plus elevating the main inlet jetties, results in the greatest level of improvement throughout Nantucket Harbor relative to the TMDL. However, Scenario 3 yields nearly identical results, indicating that almost all of the improvement in the combined Scenario 4 results were due to the increase in tidal flushing resulting from the modification of the jetties. Both Scenario 3 and Scenario 4 attain the threshold nitrogen level/TMDL 2 Note that connecting these 262 parcels within the existing sewer district (according to the Town database), would have a similar effect on lowering watershed wastewater nitrogen as the reductions proposed in Scenario 1. (0.350 mg/L TN)at the sentinel station within the Head of the Harbor and both are extremely close to the threshold level/TMDL (0.355 mg/L TN) at the secondary sentinel station within Polpis Harbor. It should also be noted that all of thescenarios (1,2,3,4) are based upon existing, not build-out, conditions, the Town must mitigate any new loads from new development to sustain the improvements in any of the scenarios. These results indicate that sewer extension to Monomoy and Shimmo areas, alone, is insufficient to meet the threshold targets for restoring Nantucket Harbor’s impaired resources. The elevation of the jetties provides more improvement in nitrogen levels, but also is insufficient on its own to meet the threshold nitrogen level/TMDL at both sentinel stations. Both sewer extension and alteration of hydrodynamics hadpositive effects on nitrogen levels. It should also be noted that the parcel analysis conducted within the existing Town sewered area indicated that a large number of parcels may not presently be connected to the existing sewer system presenting an opportunity for additional removal of septic nitrogen (if the town database can be confirmed). Figure 1. Nantucket Harbor Existing and Proposed Wastewater Collection Areas. The area colored yellow indicates the existing sewer collection area, while the parcels outlined in red are in the Scenario 1/Monomoy collection area and the parcels outlined in purple are in the Shimmo collection area. Scenario 2 combines the Monomoy and Shimmo collection areas. Subwatershed boundaries for Nantucket Harbor are shown in green. Scenario 3 uses existing nitrogen loads and elevates the inlet jetties, increasing tidal flushing. Scenario 4 combines the results of Scenario 2 withelevating the main jetties to the Harbor. Existing Sewer Area Monomoy Sewer Area KEY Shimmo Sewer Area Nantucket Harbor Watershed Table 1.Nitrogen loads used for Scenario 1. The difference between the present watershed load and Scenario 1 stems from the removal of septic system wastewater nitrogen load from the Monomoy area (Figure 1). Subwatershed Area Present Watershed (kg/day) Scenario 1 Watershed (kg/day) Atmospheric (kg/day) Benthic (kg/day) Head of the Harbor 1.858 1.858 22.239 -17.082 Polpis Harbor 3.529 3.529 2.190 27.370 Quaise 2.123 2.123 20.126 43.643 Town 15.901 15.208 13.888 -2.775 Table 2.Nitrogen loads used for Scenarios 2 and 4. The difference between the present watershed load and Scenario 1 stems from the removal of septic system wastewater nitrogen load from the Monomoy and Shimmo areas (Figure 1). Subwatershed Area Present Watershed (kg/day) Scenarios 2 & 4 Watershed (kg/day) Atmospheric (kg/day) Benthic (kg/day) Head of the Harbor 1.858 1.858 22.239 -16.953 Polpis Harbor 3.529 3.529 2.190 27.335 Quaise 2.123 1.962 20.126 43.517 Town 15.901 14.784 13.888 -2.775 Table 3.Nitrogen loads used for Scenarios 3. Since this scenario only involves the elevation of the jetties, the present watershed nitrogen load, atmospheric load, and benthic flux is the same as used in the MEP Threshold Report assessment of existing conditions. Subwatershed Area Present Watershed (kg/day) Scenarios 3 Watershed (kg/day) Atmospheric (kg/day) Benthic (kg/day) Head of the Harbor 1.858 1.858 22.239 -17.211 Polpis Harbor 3.529 3.529 2.190 27.441 Quaise 2.123 2.123 20.126 43.896 Town 15.901 15.901 13.888 -2.793 Table 4.Results of watershed loading reductions and elevation of jetties detailed as Scenarios 1-4 above. Total nitrogen concentrations at each water quality station under present conditions and for each scenario are presented in mg/L. Sentinel stations (stations 2.1 and 4) are shown in bold. TN threshold levels at the respective sentinel stations are 0.350 and 0.355 mg/L. Station Station ID Present TN mg/L Scenario 1 mg/L Scenario 2 mg/L Scenario 3 mg/L Scenario 4 mg/L Head of the Harbor-Upper 2 0.397 0.396 0.396 0.395 0.394 Head of the Harbor- Mid 2.2 0.390 0.389 0.388 0.387 0.387 Head of the Harbor- Lower 2.1 0.353 0.352 0.352 0.350 0.349 Pocomo Head 3 0.340 0.339 0.339 0.336 0.336 Quaise Basin 3.1 0.325 0.325 0.324 0.321 0.321 East Polpis 4 0.361 0.361 0.360 0.357 0.357 West Polpis 4.1 0.371 0.370 0.370 0.367 0.367 Abrams Point 5 0.296 0.296 0.296 0.292 0.292 Monomoy 6 0.291 0.290 0.290 0.287 0.286 Mooring Area 7 0.285 0.284 0.284 0.281 0.281 1 --------------------------------- Technical Memorandum --------------------------------- To: Rosemary Blaquier, Woodard and Curran Kara Buzanoski, Town of Nantucket From: Brian Howes, Director Coastal Systems Program Ed Eichner, Coastal Systems Program Roland Samimy, Coastal Systems Program John Ramsey, Applied Coastal Research & Engineering, Inc. Sean Kelley, Applied Coastal Research & Engineering, Inc. RE: Round 2 Scenarios: Nantucket Harbor MEP Modeling Results in support of CWMP Update Date: February 4, 2014 ------------------------------------------------------------------------------------------------------------------------------- The Massachusetts Estuaries Project (MEP) completed an assessment of Nantucket Harbor in 2006.1 The MEP assessment included an assessment of the ecological status of the Harbor and development of a calibrated and validated water quality model linked to a watershed nitrogen loading model. This assessment indicated that the Harbor system had portions that were moderately impaired (i.e., Polpis Harbor and Head of Harbor) based on loss of historic eelgrass, impacted benthic communities, and periodic oxygen depletion. MEP staff developed recommended nitrogen thresholds to restore the system. These thresholds were converted into Total Maximum Daily Loads (TMDLs) by the Massachusetts Department of Environmental Protection2 and approved by the US Environmental Protection Agency. The MEP team has worked closely with the Town of Nantucket to use the MEP linked model to evaluate potential options to restore the Nantucket Harbor water quality and meet the TMDLs. The present Memorandum details the results from a second round of estuary water quality scenario runs for Nantucket Harbor in support of the Town of Nantucket CWMP.3 The details of these scenario runs were developed in consultation with the Town’s CWMP consultants (Woodard and Curran) and were completed using an updated version of the MEP linked model. The effects of the proposed watershed and flushing alterations on nitrogen levels throughout the waters of the Nantucket Harbor System are compared to the TMDL 1 Howes B., S.W. Kelley, J.S. Ramsey, R. Samimy, D. Schlezinger, and E. Eichner. 2006. Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Nantucket Harbor, Town of Nantucket, Nantucket Island, MA. Massachusetts Estuaries Project, Massachusetts Department of Environmental Protection. Boston, MA. 183 pp. 2 Nantucket Harbor Embayment System Total Maximum Daily Loads For Total Nitrogen. January 28, 2009. Report # 97-TMDL-2 Control #249.0. Commonwealth of Massachusetts, Department of Environmental Protection. 3 First round of scenarios were detailed in a January 4, 2012 CSP Technical Memorandum from MEP team to David Fronzuto and Richard Ray of the town. 2 thresholds needed to achieve restoration. The Round 2 Scenarios discussed in this memorandum focus on: a) updating the watershed nitrogen loading model to reflect the correction parcels connected to the municipal sewer system that were previously classified as being on septic, b) increased tidal flushing of Polpis Harbor based on planned dredging, c) increased tidal flushing of the overall Nantucket Harbor system based on elevation of the jetty structure that defines the entrance to the harbor and d) nitrogen management strategies (sewering) to be undertaken within the Monomoy service area. Nantucket Harbor Scenarios: Round 2 Results Scenario staff worked with the Town and the Town’s CWMP consultant to develop the details of the scenarios. The consultants supplied base information, including GIS coverages, that was used in the completion of the scenarios. Each scenario description below includes the review of the base information and scenario details. Scenario 1: Update the Nantucket Harbor MEP Watershed Nitrogen Loading Model to reflect Historically Sewered Parcels Scenario staff was asked to update the existing MEP watershed nitrogen loading to the Harbor to reflect revised listing of properties connected to the municipal sewer system. The parcel information utilized during both the original MEP assessment and the first round of scenarios was originally supplied by the town. Town staff completed a comprehensive review of this parcel information and indicated that there were 478 parcels within the Town Sewer District that were originally identified as connected to septic systems that were actually tied in to the Town of Nantucket Sewer system. These properties were not included in the town sewer billing databases, but are connected to the sewer system and have generally been connected for a number of years. Woodard and Curran utilized this updated database to indicate that 197 of these parcels are located within the Nantucket Harbor watershed. This review also found that there were also 5 parcels that were initially indicated as being sewered, but rely on septic systems for wastewater treatment. Scenario staff reviewed the updated GIS parcel coverage and database and compared the results to the sewered parcels identified in the MEP watershed nitrogen loading model for Nantucket Harbor. This review indicated the following: a) 115 of the 197 watershed parcels were already considered sewered in the MEP model, b) 35 were new parcels created since the original MEP land use database was received from the Town, so they would be counted in the buildout scenario rather than existing conditions, c) 9 were duplicate parcel listings, and d) 38 were previously identified as utilizing septic systems for wastewater treatment (among these are 4 that were listed as undeveloped lots in the original MEP land use database). The 38 newly-identified sewered parcels were corrected in the MEP watershed nitrogen loading model. Among the 38 parcels are six that were listed in the MEP land use database as developable residential parcels and that have subsequently been developed and are now listed in the 2013 land use database as developed properties (either single family or multi-family residences). If these parcels are maintained as undeveloped, the change in the remaining 32 from septic to sewer plus the 5 parcels changed from sewered to septic results in a decrease in the existing conditions system nitrogen load of 25 kg/yr or 0.08% of the total load (Table 1). If the 35 new parcels and the 6 parcels developed since the MEP 3 assessment are both added to the nitrogen loading model, the nitrogen load would increase slightly due to the associated increases in fertilized lawn areas and impervious surfaces. The relatively small change in the MEP existing conditions nitrogen load means the MEP water quality model does not need to be recalibrated and can be used to assess the impact of the other scenarios. The original estimated error in the MEP water quality model for predicting measured nitrogen concentrations was 5.1%.4 If one adds the nitrogen contributions from the harbor sediments to the updated watershed nitrogen load incorporating the corrected sewer properties, the cumulative system nitrogen loading change is less than the 0.08% change in the watershed load. Since this change is significantly less than the estimated error in the water quality modeling, no change in the calibration of the water quality model is required and it can be used for modelling of the other scenarios. Scenario 2: Update the Nantucket Harbor MEP Watershed Nitrogen Loading Model Buildout Conditions Scenario 2 was developed to review and confirm an alternative buildout scenario included in the Nantucket Harbor MEP Report that included sewering of all sewer district properties. The 2006 MEP report includes two buildout assessments: a) a standard MEP buildout assuming subdivision of all qualifying properties according to minimum lot sizes specified in the then-current town zoning regulations and b) an alternative assessment assuming that all potential future properties within the municipal sewer district, both existing and new buildout ones, are connected to the sewer system. Since the sewer system removes all wastewater nitrogen loads from the Nantucket Harbor watershed, new development within the sewer district only contributes watershed nitrogen loads from roads, roofs, and fertilized lawns in the alternative buildout scenario. The current Scenario 2 was developed in order to assess the impact of any changes in the original MEP buildout assessment in light of the findings in Scenario 1. For the current project, scenario staff initially reviewed the boundaries of the sewer district and found that the boundaries have also changed since the MEP assessment (Figure 1). The most significant changes in the district boundaries are outside of the Nantucket Harbor watershed; the changes within watershed are relatively minor. There are seven (7) properties within the watershed that have been added to the sewer district since the initial MEP assessment. In addition, as mentioned in Scenario 1, there are 35 new parcels that have been created since the MEP assessment. Many of these parcels were anticipated and were included in the original MEP alternative buildout scenario, but some of the new development occurred on properties that were originally assessed as having no additional development potential (e.g., properties previously classified as the town assessor as undevelopable). These properties have been included in the updated buildout scenario. The net result of the expansion of the sewer district and the buildout additions to the MEP Nantucket Harbor buildout scenario with sewering for all properties within the town sewer district is relatively insignificant increase of 17.5 kg/yr (a 0.06% increase) from the original MEP alternative buildout assessment. This updated buildout scenario is the starting point for the changes in the inlet to Polpis Harbor/the main Harbor jetties in Scenario 3 and the inclusion of sewering in the Monomoy needs area evaluated in Scenario 4. Scenario 3: Dredging the Inlet to Polpis Harbor and Elevating the Nantucket Harbor Inlet jetties Scenario 3 was developed to evaluate the water quality impacts of the planned dredging of the inlet to Polpis Harbor and the modification of the Nantucket Harbor inlet jetty structure to reflect the US Army Corps of Engineers approved height of +3 feet (MLW +1). The existing MEP hydrodynamic and water quality model was slightly modified to reflect the ACOE existing conditions and the model’s calibration 4 Figure VI-3 (p. 111) in the Nantucket Harbor MEP report. 4 was checked; the calibration held and the model was then modified to reflect the proposed changes. All changes were based on materials submitted to the scenario staff by the town. The watershed nitrogen loading in this scenario is based on the updated buildout TN loading to Nantucket Harbor as completed under Scenario 2, while the atmospheric deposition and net benthic flux are the same as developed originally under the MEP (Table 2). Scenario staff reviewed and confirmed the details of the dredging and jetty configurations with Woodard and Curran staff before proceeding with the scenario. The combined effect of dredging of the inlet to Polpis Harbor and the modification of the Nantucket Harbor inlet jetty structure does not attain the TN thresholds at either of the system sentinel stations (Table 3). The changes in this scenario reduce the TN concentration at the Head of the Harbor sentinel station closer to the 0.350 mg/L TN threshold compared to the buildout conditions in Scenario 2, but the threshold concentration is not attained. Similarly, the TN threshold concentration is not attained at the East Polpis sentinel station either. The East Polpis Harbor sentinel station TN concentration increases above the buildout concentration (0.3605 mg/L to 0.3614 mg/L). TN concentrations decrease throughout the system except for the increase at the East Polpis Harbor sentinel station. Increases in TN concentrations are often seen where dredging within the interior of a bay increases the volume of water that needs to be flushed out by the tides; water lingers longer in the system and, therefore, TN concentrations increase. Scenario 4: Combine Sewering of Monomoy Needs Area with Scenario 3 changes Scenario 4 was developed to evaluate the nitrogen concentration changes in Nantucket Harbor resulting from combining the: a) Scenario 3 changes (elevated jetty at Harbor entrance, dredging of Polpis Harbor inlet), b) Scenario 2 sewering of all developed and future buildout properties within the town Sewer District, and c) sewering of an additional set of parcels within the Monomoy Sewer Needs Area (Figure 2). The Monomoy Sewer Needs Area contains 168 parcels; 76% of the parcels are residential units (land use codes 101 or 109). This sewer needs area is different than the Monomoy area that was identified during the first round of scenarios for Nantucket Harbor.5 The sewering of the current Monomoy Sewer Needs Area reduces the Nantucket Harbor buildout load in Scenario 2 by 187 kg/yr (see Table 1). The combined effect of all the changes in this scenario does not attain the TN thresholds at either of the sentinel stations for Nantucket Harbor (see Table 3). The additional reduction in watershed nitrogen loading in the Town subwatershed further reduces the TN concentration at the Head of Harbor sentinel concentration below the TN concentration result in Scenario 3, but the 0.350 threshold is not attained. The sewering in the Monomoy needs area does not change the TN concentration at the East Polpis sentinel station in Scenario 3 (0.3614 mg/L in both Scenario 3 and 4). TN concentrations decrease throughout the system except for the increase at the East Polpis Harbor sentinel station; the decreases are generally greater than those modeled in Scenario 3. Further Discussion • None of the scenarios attain the threshold TN concentrations at the two sentinel stations. • Scenario 1 (existing conditions) has TN concentrations that are closest to the threshold concentrations at the sentinel stations. • Scenario 2 (buildout conditions) increases the TN concentrations at both sentinel stations with a greater increase projected at the East Polpis sentinel station. This suggests that this more interior sentinel station is more sensitive to watershed nitrogen loading increases. The watershed load 5 January 4, 2012 CSP Technical Memorandum, Figure 1 5 increase in the Polpis subwatershed is proportionally larger (+16%) than in the Town subwatershed (+4%). • Most of the increase in the Polpis subwatershed (60%) is septic system wastewater, as opposed to only 13% in the Town subwatershed. Lawn fertilizer loads are the predominant load (54%) in the Town subwatershed, followed by roads (24%), wastewater, and roofs. • Scenario 3 (buildout watershed conditions with elevation of the Nantucket Harbor inlet jetties, and dredging in Polpis Harbor inlet) reduces TN concentrations throughout the system except for the East Polpis sentinel station, where the TN concentration increased. This scenario results show that the increase in volume created by the dredging in Polpis Harbor has a greater impact on TN concentrations in Polpis than the increased tidal flushing created by the changes in the inlet. • Scenario 4 (scenario 2 changes plus sewering in the Monomoy Sewer Needs area) generally reduces TN concentrations throughout the system at greater reductions than Scenario 3 except for the East Polpis sentinel station, where the TN concentration remains the same. The sewering of the Monomoy area reduces the TN concentration at the Head of the Harbor sentinel station to a level less than the watershed buildout condition (Scenario 2), but not less than existing condition (Scenario 1) or the threshold TN concentration (0.350 mg/L). • Comparison of Scenario 3 and Scenario 4 results seem to indicate that the planned dredging of the Polpis Harbor inlet will make the TN concentration at the East Polpis sentinel station somewhat less sensitive to changes in watershed loading in other portions of the Nantucket Harbor system watershed. • Overall, the scenario results suggest that watershed management strategies should review nitrogen loading plans that address 1) septic system loads outside of the current sewer district, 2) lawn and stormwater loads with a particular focus on the Town subwatershed, and 3) future development and buildout within the watershed. For tidal management strategies, Scenario 3 demonstrates the general benefits of raising the jetties at the Harbor inlet, but the proposed dredging of the Polpis Harbor inlet will require additional watershed nitrogen reductions in order to balance the increase in Polpis Harbor TN concentration caused by the dredging. The MEP team is available to continue to assist the Town and Woodard and Curran with evaluations of planned water quality management strategies. 6 Table 1. Nantucket Harbor Watershed Nitrogen Loads used for Scenarios. Whole system and subwatershed nitrogen loads are shown (in kg/yr) for scenarios evaluated in this Technical Memo. Nitrogen loads developed in the MEP Nantucket Harbor Report are also provided for comparison. Brief descriptions of the scenarios are: Scenario 1 nitrogen loads are based on existing conditions and are modified from the original MEP existing conditions based on new information provided by the town about properties connected to the municipal sewer system. All changes in properties occurs in the Town subwatershed and changed the subwatershed nitrogen load from the original MEP existing conditions by <0.5%. Scenario 2 assumes development of all developable properties according to town zoning (i.e., buildout conditions) where all properties within the municipal sewer district are connected to the sewer system. This is the same assumption as an alternative buildout included in the original MEP Report and includes the corrections noted in Scenario 1. All changes in properties occurs in the Town subwatershed and changed the subwatershed nitrogen load from the original MEP alternative buildout conditions by <0.5%. Scenario 3 uses the Scenario 2 watershed loads assumes raising the main Harbor jetties to the USACOE recommended height and implementation of the proposed dredging within the inlet to Polpis Harbor. Scenario 4 uses the same system modifications in Scenario 3 and further modifies the watershed buildout loads by assuming that the properties within the Monomoy sewer service area are connected to the municipal sewer system. It should be noted that this service area is different than the area with the same label included in the first round of scenarios completed for Nantucket Harbor. NameWatershed ID#UnAtten N LoadAtten %Atten N LoadUnAtten N LoadAtten %Atten N LoadUnAtten N LoadAtten %Atten N LoadUnAtten N LoadAtten %Atten N LoadUnAtten N LoadAtten %Atten N LoadNantucket Harbor29852 29852 29877 29877 30579 30579 30562 30562 30393 30393Head of the Harbor8795 8795 8795 8795 8984 8984 8984 8984 8984 8984Head of the Harbor1 678678678678867867867867867867Head of the Harbor Estuary surface deposition8117811781178117811781178117811781178117Polpis2087 2087 2087 2087 2294 2294 2294 2294 2294 2294Polpis2 1288128812881288149414941494149414941494Polpis Estuary surface deposition799799799799799799799799799799Quaise8121 8121 8121 8121 8225 8225 8225 8225 8225 8225Quaise3 775775775775878878878878878878Quaise Estuary surface deposition7346734673467346734673467346734673467346Town10849 10849 10873 10873 11077 11077 11059 11059 10890 10890Town4 5780578058045804600860085990599058215821Town Estuary surface deposition506950695069506950695069 5069506950695069Original MEP Alt Buildout N LoadsScenario 4 Buildout N Loads: MonomoyScenario 1 Existing N LoadsOriginal MEP Existing N LoadsScenario 2 and 3 Buildout N Loads 7 Table 2. Sub-embayment and surface water nitrogen loads used for total nitrogen modeling of the Nantucket Harbor system in Scenarios 1, 2, 3 and 4. Total watershed N loads, atmospheric N loads, and benthic flux are shown for a) Scenario 1 existing conditions, b) Scenario 2 and 3 buildout conditions with all properties within the existing sewer district connected to the municipal system, and c) Scenario 4 buildout conditions with all properties within the existing sewer district and properties within the Monomoy service area connected to the municipal sewer system. These loads represent the loading conditions for the listed sub-embayments and used in the water quality model. Totals may not add due to rounding. a) Existing: properties connected to the municipal sewer system based on town data (corrected based on Scenario 1 findings) b) Buildout: all properties in existing sewer district connected to the municipal sewer system (corrected based on Scenario 2 findings; also used in Scenario 3) c) Buildout: all properties in existing sewer district and properties within the Monomoy service area connected to the municipal sewer system (used in Scenario 4) Sub-watershed Watershed Load (kg/day) Direct atmospheric deposition (kg/day) Benthic flux net (kg/day) Watershed Load (kg/day) Direct atmospheric deposition (kg/day) Benthic flux net (kg/day) Watershed Load (kg/day) Direct atmospheric deposition (kg/day) Benthic flux net (kg/day) Head of the Harbor 1.86 22.24 62.71 2.38 22.24 62.86 2.38 22.24 62.81 Polpis Harbor 3.53 2.19 27.44 4.09 2.19 27.67 4.09 2.19 27.58 Quaise 2.12 20.13 43.90 2.40 20.13 43.90 2.40 20.13 44.15 Town 15.84 13.89 -2.79 16.46 13.89 -2.81 15.95 13.89 -2.79 System Total 23.35 58.44 131.25 25.33 58.44 131.62 24.82 58.44 131.74 8 Table 3. Total nitrogen concentrations for the modeled Nantucket Harbor scenarios. Total nitrogen concentrations at each water quality station under present conditions and for each scenario are presented in mg/L. Sentinel stations (stations 2.1 and 4) are shown in bold. TN threshold levels at the respective sentinel stations are 0.350 and 0.355 mg/L. Changes between scenarios are based on comparison to offshore Nantucket Sound TN concentration (0.267 mg/L in these calculations); this comparison emphasizes the change between scenarios. Scenario 1 Scenario 2 Compare 1 and 2 Scenarios 3 Compare 2 and 3 Scenario 4 Compare 2 and 4 Compare 3 and 4 Station Station ID Existing Loads Buildout Loads Change above bkg Buildout Loads, rebuilt jetties, Polpis Harbor inlet dredging Change above bkg Buildout Loads, rebuilt jetties, Polpis Harbor inlet dredging, Monomoy Sewer Change above bkg Change above bkg Head of the Harbor - Upper 2 0.4111 0.4124 +0.9% 0.4121 -0.2% 0.4118 -0.4% -0.2% Head of the Harbor - Mid 2.2 0.4011 0.4023 +0.9% 0.4020 -0.2% 0.4017 -0.4% -0.2% Head of the Harbor - Lower 2.1 0.3539 0.3548 +1.0% 0.3544 -0.5% 0.3542 -0.7% -0.2% Pocomo Head 3 0.3380 0.3388 +1.1% 0.3383 -0.7% 0.3382 -0.8% -0.1% Quaise Basin 3.1 0.3234 0.3241 +1.2% 0.3236 -0.9% 0.3235 -1.1% -0.2% East Polpis 4 0.3590 0.3605 +1.6% 0.3614 +1.0% 0.3614 +1.0% 0.0% West Polpis 4.1 0.3690 0.3705 +1.5% 0.3703 -0.2% 0.3703 -0.2% 0.0% Abrams Point 5 0.2957 0.2961 +1.4% 0.2954 -2.4% 0.2954 -2.4% 0.0% Monomoy 6 0.2908 0.2911 +1.3% 0.2905 -2.5% 0.2903 -3.3% -0.9% Mooring Area 7 0.2847 0.285 +1.7% 0.2843 -3.9% 0.2842 -4.4% -0.6% 9 Figure 1. Comparison of Nantucket Sewer Districts 2006 and 2012. The orange line shows the Nantucket Harbor MEP watershed, while the yellow line outlines the October 2012 municipal sewer district. The red lines show the former 2006 boundaries of the sewer district, which was used for the MEP Nantucket Harbor assessment (Howes, et al., 2006). Scenario 2 assumes all properties within the sewer district are connected to the municipal sewer system and utilizes the 2012 delineation. As a result, seven (7) properties, which were excluded from the sewer district in the original MEP assessment, are included in the district in Scenario 2 evaluation. 10 Figure 2. Monomoy Sewer Needs Area: Nantucket Harbor Watershed. The orange line shows the Nantucket Harbor MEP watershed, while the yellow line outlines the October 2012 municipal sewer district and the parcels outlined in red are included in the Monomoy Sewer Needs area. Scenario 4 evaluates the nitrogen water quality impact of connecting the properties in the Monomoy area to the municipal sewer system combined with the Scenario 3 system configuration changes to the Harbor inlet jetties and the inlet to Polpis Harbor. The Monomoy area includes 168 parcels of which 76% are residential land uses. 1 --------------------------------- Technical Memorandum --------------------------------- To: Rosemary Blaquier, Woodard and Curran Kara Buzanoski, Town of Nantucket From: Brian Howes, Director Coastal Systems Program Ed Eichner, Coastal Systems Program Roland Samimy, Coastal Systems Program John Ramsey, Applied Coastal Research & Engineering, Inc. Sean Kelley, Applied Coastal Research & Engineering, Inc. RE: Comprehensive Scenario Review and Round 3 Scenario Results: Nantucket Harbor MEP Modeling Results in support of CWMP Update Date: May 30, 2014 ------------------------------------------------------------------------------------------------------------------------------- The Massachusetts Estuaries Project (MEP) completed an assessment of Nantucket Harbor in 2006.1 The MEP assessment included an assessment of the ecological status of the Harbor and development of a calibrated and validated water quality model linked to a watershed nitrogen loading model. This assessment indicated that the Harbor system had portions that were moderately impaired (i.e., Polpis Harbor and Head of Harbor) based on loss of historic eelgrass, impacted benthic communities, and periodic oxygen depletion. MEP staff developed recommended nitrogen thresholds to restore the system. These thresholds were converted into Total Maximum Daily Loads (TMDLs) by the Massachusetts Department of Environmental Protection2 and approved by the US Environmental Protection Agency. The MEP team has worked closely with the Town of Nantucket to use the MEP linked model to evaluate potential options to restore the Nantucket Harbor water quality and meet the TMDLs. The present Memorandum reviews all of the scenarios completed to date and details the results from a third round of estuary water quality scenario runs for Nantucket Harbor in support of the Town of Nantucket CWMP.3 Details of scenario runs, including the third round of runs, were developed in consultation with the Town’s CWMP consultants (Woodard and Curran) and town staff. Each run has included changes in the watershed nitrogen loading and/or the configuration 1 Howes B., S.W. Kelley, J.S. Ramsey, R. Samimy, D. Schlezinger, and E. Eichner. 2006. Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Nantucket Harbor, Town of Nantucket, Nantucket Island, MA. Massachusetts Estuaries Project, Massachusetts Department of Environmental Protection. Boston, MA. 183 pp. 2 Nantucket Harbor Embayment System Total Maximum Daily Loads For Total Nitrogen. January 28, 2009. Report # 97-TMDL-2 Control #249.0. Commonwealth of Massachusetts, Department of Environmental Protection. 3 First round of scenarios were detailed in a January 4, 2012 CSP Technical Memorandum from MEP team to David Fronzuto and Richard Ray of the town. Second round were detailed in a February 4, 2014 CSP Technical Memorandum from MEP team to Rosemary Blaquier, Woodard and Curran and Kara Buzanoski, Town of Nantucket. 2 of the Harbor inlet and/or bathymetry. All of these changes have been incorporated into revised versions of the MEP linked model. The effects of the proposed watershed and flushing alterations on nitrogen levels throughout the waters of the Nantucket Harbor System are compared to the MassDEP/USEPA TMDL thresholds needed to achieve restoration. Nantucket Harbor Scenarios: Round 3 Results Scenario staff worked with the Town and the Town’s CWMP consultant to develop the details of the Round 3 scenarios. Woodward and Curran supplied base information, including GIS coverages, which was used in the completion of the scenarios. Each scenario description below includes the review of the scenario details. Round 3, Scenario 1 (overall Scenario 9): Hybrid Watershed Land Use, Sewering of Monomoy Needs Area, and Raised Jetties In Scenario 1, existing land use development patterns were used, but watershed nitrogen loads are adjusted based on the assumption that all developed properties within the Town Sewer District will be connected to the Town of Nantucket Sewer system, including those that are in the District, but are not currently connected. This land use pattern does not include any additional new development over present conditions. This scenario also includes the sewer connection updates that were identified in the Round 2 scenarios (Scenario 5). In addition, all properties within the Monomoy Needs Area are also connected to the Town Sewer system. Finally, this scenario also includes the effect of raising the elevation of the jetties at the Harbor Inlet to reflect the US Army Corps of Engineers approved height of +3 feet (MLW +1). Watershed nitrogen loads, by sub-watershed, for this scenario are shown in Table 1. Round 3, Scenario 2 (overall Scenario 10): Hybrid Watershed Land Use, Sewering of Monomoy Needs Area, Lawn Fertilizer Restriction, and Raised Jetties In Scenario 2, the hybrid land use developed in Scenario 1 was used, along with the raising of the Harbor inlet jetties. The land use nitrogen loads in this scenario also includes a potential nitrogen reduction from a lawn fertilizer restriction applied throughout the Harbor System watershed. The fertilizer reduction relates to the Town’s recent efforts to reduce this nitrogen source. Current town BMP manual and regulation limit annual fertilizer N applications to 3 lbs/1,000 sq ft of lawn and individual N applications to 0.5 lbs/1,000 sq ft. Review of information gathered in the development of the BMP manual shows that healthy lawns can be sustained through minimal use of nitrogen fertilizers. Reduction of nitrogen fertilizer additions from an upper limit of 3 lbs/1,000 sq ft/yr can occur through established practices such as a) recycling of clippings, b) balancing of fast and slow release nitrogen applications, c) use of various nitrogen sources (compost, leaf litter, fertilizers), d) "spoon feeding" of nitrogen, and e) use of grasses and other ground cover with low fertilizer needs. Combining these practices with other established healthy turf practices, such as regular aeration, irrigation, and assessment of nutrient needs, can maintain the turf appearance and wear goals while minimizing nitrogen leaching into coastal waters. The MEP lawn fertilizer N loading rate (1.08 lbs/1,000 sq ft) was developed based on a thesis- level review of fertilizer practices of over 2,300 residences in three towns on Cape Cod. A 3 similar review has not been completed on Nantucket, but town and CWMP project staff observations within the Nantucket Harbor watershed seem to indicate that the majority of homeowners do not utilize fertilizers and most of the turf areas within the watershed are long- established and, therefore, would require only low levels of N application. In addition, CWMP staff consulted with MEP staff and found that selected golf courses, which rely on healthy turf and were contacted during MEP assessments, sustained various high-use turf types with low N application rates (1.2 to 1.7 lbs/1,000 sq ft/yr). It is thought that if professional turf areas such as golf courses can sustain turf that is extensively used, then more ornamental turf areas such as lawns can be sustained with even lower N application rates and proper maintenance. Given Nantucket's interest in reducing nitrogen loading to coastal waters, these consultations with MEP staff, and the willingness of the town to institute formal fertilizer reduction rules, CWMP staff selected a reduced N application rate (0.9 lbs/1,000 sq ft/yr) for use in this scenario. This annual rate is thought to be reasonably conservative given CWMP staff watershed observations and estimated homeowner practices. In this scenario, this rate was applied to 75% of the homeowners within the whole Nantucket Harbor watershed with the remaining 25% utilizing the standard MEP lawn fertilizer loading factor. This application split is based on regulatory compliance rates observed for similar turf limits approved within the Chesapeake Bay watershed. The net result of the inclusion of all these factors is that the standardized N application rate for turf areas within the Nantucket Harbor watershed is reduced to 0.945 lbs/1,000 sq ft/yr for this scenario. Watershed nitrogen loads, by sub-watershed, for this scenario are shown in Table 1. Round 3, Scenario 3 (overall Scenario 11): Hybrid Watershed Land Use, Sewering of Monomoy Needs Area (adjusted), Lawn Fertilizer Restriction, and Raised Jetties During the midst of the preliminary review of results from Scenarios 1 and 2, questions arose about the delineation of the Monomoy Needs Area. This issue had previously arisen during the development of the Round 2 scenarios because there had been updates in the Town Sewer District that necessitated changes in the Monomoy Needs Area delineation previously evaluated during the Round 1 scenarios. As a result, additional properties along Brewster Road were excluded from the Monomoy Needs Area during the Round 2 scenarios and during Round 3, Scenarios 1 and 2 discussed in this Technical Memorandum (Figure 1). For the present Round 3, Scenario 3 analysis, these properties were included along with the other changes previously included in Scenario 2. The inclusion of these properties in the Monomoy Needs area reduced the overall system watershed load by <0.1%. Watershed nitrogen loads, by sub-watershed, for this scenario are shown in Table 1. Comprehensive Review of Nantucket Scenario Results (including Round 3 Scenarios) Table 1 shows the watershed nitrogen loadings for all eleven (11) of the MEP scenarios conducted to date, including the scenarios discussed in this Technical Memorandum. Table 1 also shows the original scenarios in the MEP report. Table 2 shows the water quality modeling results, including concentrations at the TMDL threshold stations (2.1 and 4). The respective total nitrogen (TN) threshold concentrations are: 0.350 mg/L at Head of the Harbor – Lower (Station 2.1) and 0.355 mg/L at East Polpis (Station 4). The scenarios developed to date have include proposed changes in the Nantucket Harbor system configuration to improve tidal 4 flushing (e.g., raising the Harbor inlet jetties) and reductions in watershed nitrogen loads (e.g., wastewater N removal by sewering portions of the watershed). Scenarios have also evaluated differences in land use loads over time (i.e., looking at existing and buildout conditions). The completion of the scenarios has provided quantitative information as to which changes provide the largest reductions in nitrogen concentrations. The initial scenarios in the MEP Nitrogen Threshold Report were conducted to establish a baseline to review potential management options.4 Development of the existing conditions scenario combines all the various nitrogen loads from the watershed, on the surface of the Harbor, and regeneration from the sediments with the physical characteristics of the Harbor, including its volume and tidal movements, and ensures that the model results reasonably match the measured water quality throughout the Harbor System. Once this baseline is established and verified with field data, the model can then be used to reliably assess impacts of changes in the various nitrogen sources. Included in the original MEP report were five scenarios, including two buildout versions, a no anthropogenic loading scenario, and two scenarios demonstrating two of the many alternatives by which the threshold concentrations can be attained. It should be noted that the threshold concentrations can be attained any number of ways; MassDEP generally requires at least one scenario indicating that the threshold concentration can be attained before the MEP report is finalized. A total of eleven (11) scenarios (numbered 1-11 in Table 1) have been developed since the completion of the MEP report, including those described as Round 3 in this Technical Memorandum (described above). These scenarios have been developed through discussions between MEP staff and town staff and consultants and have included various refinements to portions of the linked Nantucket Harbor watershed/estuary models. Some of these refinements have created circumstances where past and current scenarios cannot be easily compared because the base model configuration has been updated based upon new information developed as part of the scenario process. For example, while the new existing conditions scenario (overall Scenario 5 in Table 1) did not have a substantial change in the watershed nitrogen loading, there was a refinement in treatment of the benthic flux in the water quality model for the Head of the Harbor that evolved from the conduct of the previous scenarios. This change in benthic flux did not alter the calibration of the model (i.e., everything remained in balance), but it slightly altered the baseline for the system and limits the comparison between Scenarios 5-11 and Scenarios 1-4. Round 3, Scenarios 1, 2, and 3 in this Technical Memo (overall Scenarios 9, 10, 11) are sufficient to meet the TN levels needed for restoration of the Nantucket Harbor System. These scenario results round directly to the TN thresholds of 0.350 mg/L and 0.355 mg/L for the Head of Harbor and Polpis Harbor locations, respectively. There was no difference in outcome between scenario 9 vs 10 vs 11 (see Table 2). These results are based primarily upon the MEP base model with the refinements developed in concert with the Town and its consultants. It is anticipated that monitoring will continue in order to allow for adaptive management as restoration progresses. The Round 3 scenario results indicate that combining complete sewering in the Sewer District and the Monomoy Service Area with raising of the jetties at the Harbor inlet are sufficient to 4 Howes B., S.W. Kelley, J.S. Ramsey, R. Samimy, D. Schlezinger, and E. Eichner. 2006. 5 attain restoration in the system (i.e., Scenario 9). Addition of the lawn fertilizer reductions (Scenario 10) and connection of the development along Brewster Road to the sewer system (Scenario 11) reduce nitrogen loads, but only change TN concentrations by <0.001 mg/L. Scenarios results show that lawn fertilizer reductions and sewering within the Shimmo Service provide relatively smaller nitrogen reductions, although fertilizer management does provide a buffer for new unanticipated future N loads. However, implementation of these nitrogen mitigation strategies may be delayed until after the water quality impact of the other system changes are assessed. It is also worth noting that the fertilizer reductions were based on the assumptions developed for Scenario 10 above and the impact of fertilizer reduction may be more meaningful if a more significant lawn fertilizer reduction is attained (i.e., higher compliance or watershed-specific data based on post-implementation surveys).. It is also notable that the dredging of the Polpis Harbor inlet does not reduce TN concentrations in the overall Harbor and causes TN concentrations at the Polpis Harbor sentinel station to increase. This increase in TN concentration due to interior system dredging has also been noted several times in scenarios for other MEP systems, mainly on Cape Cod. This increase is based on the physics of tidal flushing: since the volume of water coming through the inlet remains the same, increasing the volume of the basin inside of the inlet, in this case Polpis Harbor, results in more water remaining in the basin (i.e. longer residence time). This water then gathers more nitrogen inputs from the watershed and sediments, so that TN concentrations increase. The scenario results indicate that dredging within the Polpis Harbor inlet will have to be offset by greater reductions in nitrogen loading inputs or an increase in system tidal volumes in order move closer to the threshold concentrations. Overall, the scenario results show which management approaches provide sufficient reductions in TN concentrations within the Harbor to meet the N threshold levels and suggest that different mixes of alternatives used in scenarios 9, 10, and 11 are possible. As these results indicate threshold levels are attained, but are at the margin of the predictive ability of the Nantucket Harbor models, we recommend an adaptive management approach that includes implementation of the most impactful management steps based on the scenario modeling and a monitoring program to regularly assess the progress toward the TMDL. This regular, on-going monitoring and feedback review of collected data will allow the town to measure the actual improvements within the Harbor system and address additional issues of future management including nitrogen loading impacts of buildout/new development within the watershed, consideration of additional lawn fertilizer restrictions, completion of sewering within the existing Town Sewer District, and expansion of sewering to other portions of the Harbor watershed. This sort of approach would also allow future refinements of the MEP models as new data helps to better understand the details within the system. The MEP team is available to continue to assist the Town and Woodard and Curran with further evaluations of planned water quality management strategies. 6 Table 1. Comprehensive Listing of Watershed Nitrogen Loads used in MEP Nantucket Harbor Scenarios. Whole system and subwatershed nitrogen loads are shown (in kg/yr) for all past scenarios and the scenarios evaluated in this Technical Memo. Scenario are grouped by the four reporting documents: 1) Nantucket Harbor MEP Report, 2) January 4, 2012 MEP Technical Memorandum [Scenarios 1-4], 3) February 4, 2014 MEP Technical Memorandum [Scenarios 5-8], and 4) this current MEP Technical Memorandum [Scenarios 9-11]. It should be noted that watershed nitrogen loads in the MEP Report and the January 4, 2012 used the same land use database and listing of parcels connected to the Town sewer system, while later scenarios used updated information developed during each subsequent group of scenarios. 123 4 5 6 7 891011Jan 4, 2012 MEP Tech Memo Scenario 1Jan 4, 2012 MEP Tech Memo Scenario 2Jan 4, 2012 MEP Tech Memo Scenario 3Jan 4, 2012 MEP Tech Memo Scenario 4Feb 4, 2014 MEP Tech Memo Scenario 1Feb 4, 2014 MEP Tech Memo Scenario 2Feb 4, 2014 MEP Tech Memo Scenario 3Feb 4, 2014 MEP Tech Memo Scenario 4May 19, 2014 MEP Tech Memo Scenario 1May 19, 2014 MEP Tech Memo Scenario 2May 19, 2014 MEP Tech Memo Scenario 3Existing BuildoutAlt BuildoutNo AnthroExisting Existing Existing Existing Existing ExistingNew ExistingNew BuildoutNew BuildoutNew BuildoutHybrid ExistingHybrid ExistingHybrid ExistingAll Sewer District connected to town sewerThreshold A: 100% removal of septic from Town subwatershed + 80% of all anthro N loads from other shedsThreshold B: 100% removal of septic from whole shedMonomoy SeweringMonomoy and Shimmo SeweringElevate JettiesMonomoy and Shimmo Sewering, Elevate JettiesUpdate Historically Sewered Properties, changes to Sewer DistrictUpdate Historically Sewered Properties, changes to Sewer DistrictDredging the Inlet to Polpis Harbor, Elevate Inlet JettiesMonomoy Sewering, Dredging the Inlet to Polpis Harbor, Elevate Inlet JettiesMonomoy Sewering, Elevate Inlet JettiesMonomoy Sewering, Lawn Fertilizer Restriction, Elevate Inlet JettiesMonomoy Sewering (adjusted), Lawn Fertilizer Restriction, Elevate Inlet JettiesWatershed NameWatershed ID#Nantucket Harbor 29,877 31,905 30,562 23,003 26,739 27,422 29,624 29,410 29,877 29,410 29,852 30,579 30,579 30,393 28,277 28,068 28,042 Head of the Harbor8,795 8,984 8,984 8,309 8,406 8,538 8,795 8,795 8,795 8,795 8,795 8,984 8,984 8,984 8,795 8,788 8,788 Head of the Harbor 1 678 867 867 192 289 421 678 678 678 678 678 867 867 867 678 671 671 Head of the Harbor Estuary surface deposition8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 8,117 Polpis2,087 2,294 2,294 1,470 1,593 1,928 2,088 2,088 2,088 2,088 2,087 2,294 2,294 2,294 2,087 2,079 2,079 Polpis 2 1,288 1,494 1,494 670 794 1,129 1,288 1,288 1,288 1,288 1,288 1,494 1,494 1,494 1,288 1,279 1,279 Polpis Estuary surface deposition799 799 799 799 799 799 799 799 799 799 799 799 799 799 799 799 799 Quaise8,121 8,225 8,225 7,673 7,762 7,978 8,121 8,062 8,121 8,062 8,121 8,225 8,225 8,225 8,121 8,114 8,114 Quaise 3 775 878 878 327 416 632 775 716 775 716 775 878 878 878 775 768 768 Quaise Estuary surface deposition7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 7,346 Town10,873 12,402 11,059 5,551 8,977 8,977 10,620 10,465 10,873 10,465 10,849 11,077 11,077 10,890 9,274 9,086 9,061 Town 4 5,804 7,333 5,990 482 3,908 3,908 5,551 5,396 5,804 5,396 5,780 6,008 6,008 5,821 4,204 4,017 3,992 Town Estuary surface deposition5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 5,069 Overall Scenario CountReferenceWatershed Land UseBrief Scenario DescriptionOriginal MEP N LoadsMEP Report 7 Table 2. Comprehensive Listing of Nantucket Harbor MEP Scenario Water Quality Results. Modeling total nitrogen concentrations (all in mg/L) at each of the Nantucket Harbor water quality sampling stations are shown, along with brief descriptions of each of the scenarios and where the results were reported. Results for the two sentinel stations (stations 2.1 and 4) are indicated in the gray shade cells; cells shaded green are scenario results that attained the threshold concentrations at the sentinel stations: 0.350 mg/L TN at station 2.1 and 0.355 mg/L at station 4. Scenarios are grouped by the four reporting documents: 1) Nantucket Harbor MEP Report, 2) January 4, 2012 MEP Technical Memorandum [Scenarios 1-4], 3) February 4, 2014 MEP Technical Memorandum [Scenarios 5-8], and 4) this current MEP Technical Memorandum [Scenarios 9-11]. It should be noted that watershed nitrogen loads in the MEP Report and the January 4, 2012 Technical Memorandum used the same land use database, including listing of parcels connected to the Town sewer system. Later scenarios used updated information developed during each subsequent group of scenarios that supports refinement of water quality modeling results. 123 4 5 6 7 891011Jan 4, 2012 MEP Tech Memo Scenario 1Jan 4, 2012 MEP Tech Memo Scenario 2Jan 4, 2012 MEP Tech Memo Scenario 3Jan 4, 2012 MEP Tech Memo Scenario 4Feb 4, 2014 MEP Tech Memo Scenario 1Feb 4, 2014 MEP Tech Memo Scenario 2Feb 4, 2014 MEP Tech Memo Scenario 3Feb 4, 2014 MEP Tech Memo Scenario 4May 19, 2014 MEP Tech Memo Scenario 1May 19, 2014 MEP Tech Memo Scenario 2May 19, 2014 MEP Tech Memo Scenario 3Existing BuildoutAlt BuildoutNo AnthroExisting Existing Existing Existing Existing ExistingNew ExistingNew BuildoutNew BuildoutNew BuildoutHybrid ExistingHybrid ExistingHybrid ExistingAll Sewer District connected to town sewerThreshold A: 100% removal of septic from Town subwatershed + 80% of all anthro N loads from other shedsThreshold B: 100% removal of septic from whole shedMonomoy SeweringMonomoy and Shimmo SeweringElevate JettiesMonomoy and Shimmo Sewering, Elevate JettiesUpdate Historically Sewered Properties, changes to Sewer DistrictUpdate Historically Sewered Properties, changes to Sewer DistrictDredging the Inlet to Polpis Harbor, Elevate Inlet JettiesMonomoy Sewering, Dredging the Inlet to Polpis Harbor, Elevate Inlet JettiesMonomoy Sewering, Elevate Inlet JettiesMonomoy Sewering, Lawn Fertilizer Restriction, Elevate Inlet JettiesMonomoy Sewering (adjusted), Lawn Fertilizer Restriction, Elevate Inlet JettiesStationStation IDHead of the Harbor - Upper 2 0.397 0.400 0.398 0.387 0.392 0.393 0.396 0.396 0.395 0.394 0.411 0.412 0.412 0.412 0.409 0.408 0.408Head of the Harbor - Mid 2.2 0.390 0.392 0.391 0.380 0.385 0.386 0.389 0.388 0.387 0.387 0.401 0.402 0.402 0.402 0.399 0.399 0.399Head of the Harbor - Lower2.1 0.353 0.355 0.354 0.345 0.349 0.350 0.352 0.352 0.350 0.349 0.354 0.355 0.354 0.354 0.352 0.352 0.352Pocomo Head3 0.340 0.342 0.340 0.333 0.336 0.337 0.339 0.339 0.336 0.336 0.338 0.339 0.338 0.338 0.336 0.336 0.336Quaise Basin3.1 0.325 0.327 0.326 0.319 0.322 0.323 0.325 0.324 0.321 0.321 0.323 0.324 0.324 0.324 0.322 0.322 0.322East Polpis4 0.361 0.364 0.363 0.351 0.356 0.358 0.361 0.360 0.357 0.357 0.359 0.361 0.361 0.361 0.357 0.357 0.357West Polpis4.1 0.371 0.374 0.373 0.360 0.365 0.367 0.370 0.370 0.367 0.367 0.369 0.371 0.370 0.370 0.367 0.367 0.367Abrams Point5 0.296 0.297 0.296 0.293 0.294 0.295 0.296 0.296 0.292 0.292 0.296 0.296 0.295 0.295 0.294 0.294 0.294Monomoy6 0.291 0.292 0.291 0.286 0.289 0.289 0.290 0.290 0.287 0.286 0.291 0.291 0.291 0.290 0.289 0.289 0.289Mooring Area7 0.285 0.286 0.285 0.282 0.284 0.284 0.284 0.284 0.281 0.281 0.285 0.285 0.284 0.284 0.283 0.283 0.283Overall Scenario CountReferenceWatershed Land UseBrief Scenario DescriptionOriginal MEP N LoadsMEP Report 8 Figure 1. Comparison of Monomoy Service Area 2011 and 2014. The area along Brewster Road, which is within the green oval, was excluded from the Monomoy Service Area in Scenarios 9 and 10 during the initial review of scenarios completed for this Technical Memorandum. These parcels were included in Scenario 11. It should also be noted that the parcels included in the Monomoy and Shimmo Service Areas changed between the development of Scenarios 4 and 5 and that the boundary of the Town Sewer District also changed over the course of Nantucket Harbor MEP scenario reviews. The Service Areas shown above in the 2014 aerial map are the current delineation with the addition of the parcels along Brewster Road. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION I ONE CONGRESS STREET SUITE 1100 BOSTON, MASSACHUSETTS 02114-2023 May 12, 2009 Laurie Burt, Commissioner Department of Environmental Protection 1 Winter Street Boston, MA 02108 Re: Approval of Nantucket Harbor Embayment System Total Maximum Daily Loads For Total Nitrogen Dear Commissioner Burt: Thank you for submission of the Total Maximum Daily Loads (TMDLs) for total nitrogen in Nantucket Harbor and the work that went into these analyses. The U.S. Environmental Protection Agency (EPA) has reviewed the document entitled “Nantucket Harbor Embayment System Total Maximum Daily Loads for Total Nitrogen (Report # 97-TMDL-2 Control #249.0)” and approves these two TMDLs. EPA has determined, as set forth in the enclosed review document, that these TMDLs meet the requirements of Section 303(d) of the Clean Water Act (CWA) and EPA’s implementing regulations at 40 Code of Federal Regulations (CFR) part 130. My staff and I look forward to continued cooperation with the MassDEP in exercising our shared responsibility of implementing the requirements under Section 303(d) of the CWA. If you have questions regarding this approval, please contact Steve Silva at (617) 918-1561 or Mary Garren at (617) 918-1322. Sincerely, /s/ Ken Moraff, Acting Director Office of Ecosystem Protection Enclosure cc: Glenn Haas, MassDEP Rick Dunn, MassDEP Brian Dudley, MassDEP Steve Silva, EPA Mary Garren, EPA EPA NEW ENGLAND’S TMDL REVIEW DATE: May 12, 2009 TMDL: Nantucket Harbor Embayment System TMDL for Total Nitrogen (Report # MA97-TMDL-2, Control #249.0) STATUS: Final IMPAIRMENT/POLLUTANT: 2 TMDLs for Total Nitrogen (See Attachment 1) BACKGROUND: The Massachusetts Department of Environmental Protection (MassDEP) released a draft TMDL on September 25, 2007 for public review. Key stakeholders received copies of the document in the mail. The draft TMDL was posted on the Department’s web site on that date as well. In addition, a public meeting was held in the Town of Nantucket, Veteran’s Community Center on October 9, 2007. The public comment period was extended and comments accepted until November 2, 2007. MassDEP prepared a response to public comment which was submitted along with the final TMDL to EPA. All comments from the public were taken into account in the Response to Comments and the final TMDL submission. MassDEP notes that the public meeting was for Nantucket Harbor and Polpis Harbor. As such their response to comments document includes responses to issues and concerns raised for both embayments. The final submission to EPA was sent on February 3, 2009. In addition to the TMDL itself, the submittal included, either directly or by reference, the following additional documents: • Response to Comments for Draft TMDL Report for the Nantucket Harbor System. (Report dated September 12, 2007) • Massachusetts Year 2008 Integrated List of Waters, Final Listing of the Condition of Massachusetts’ Waters Pursuant to Sections 303(d) and 305(b) of the Clean Water Act (CN 282.1), December, 2008. http://www.mass.gov/dep/water/resources/2008il1.pdf • Howes B., S. W. Kelley, J. S. Ramsey, R. Samimy, D. Schlezinger, and E. Eichner (2006). Linked Watershed-Embayment Model to Determine Critical Nitrogen Loading Thresholds for Nantucket Harbor, Town of Nantucket, Nantucket Island, MA. Massachusetts Estuaries Project, Massachusetts Department of Environmental Protection. Boston, MA. http://www.oceanscience.net/estuaries/Nantucket.htm • Massachusetts Estuaries Project Embayment Restoration and Guidance for Implementation Strategies, MassDEP 2003. http://www.mass.gov/dep/water/resources/mepmain.pdf The following review explains how the TMDL submission meets the statutory and regulatory requirements of TMDLs in accordance with §303(d) of the Clean Water Act and EPA’s implementing regulations in 40 CFR Part 130. REVIEWER: Mary Garren, telephone number 617-918-1322, email: garren.mary@epa.gov REVIEW ELEMENTS OF TMDLs Section 303(d) of the Clean Water Act (CWA) and EPA’s implementing regulations at 40 C.F.R. § 130 describe the statutory and regulatory requirements for approvable TMDLs. The following information is generally necessary for EPA to determine if a submitted TMDL fulfills the legal requirements for approval under Section 303(d) and EPA regulations, and should be included in the submittal package. Use of the verb “must” below denotes information that is required to be submitted because it relates to elements of the TMDL required by the CWA and by regulation. 1. Description of Waterbody, Pollutant of Concern, Pollutant Sources and Priority Ranking The TMDL analytical document must identify the waterbody as it appears on the State/Tribe’s 303(d) list, the pollutant of concern and the priority ranking of the waterbody. The TMDL submittal must include a description of the point and nonpoint sources of the pollutant of concern, including the magnitude and location of the sources. Where it is possible to separate natural background from nonpoint sources, a description of the natural background must be provided, including the magnitude and location of the source(s). Such information is necessary for EPA’s review of the load and wasteload allocations which are required by regulation. The TMDL submittal should also contain a description of any important assumptions made in developing the TMDL, such as: (1) the assumed distribution of land use in the watershed; (2) population characteristics, wildlife resources, and other relevant information affecting the characterization of the pollutant of concern and its allocation to sources; (3) present and future growth trends, if taken into consideration in preparing the TMDL; and, (4) explanation and analytical basis for expressing the TMDL through surrogate measures, if applicable. Surrogate measures are parameters such as percent fines and turbidity for sediment impairments, or chlorophyl a and phosphorus loadings for excess algae. The document for the Nantucket Harbor Embayment System TMDL for Total Nitrogen adequately describes the water body segment, nature and cause or threat of the impairments. Impairments include loss of eelgrass beds. Approximately 38% of eelgrass beds have been lost since a survey completed in 1951. There are healthy or slightly impaired conditions relative to dissolved oxygen, macro-algae, and benthic fauna. The TMDL identifies excess total nitrogen originating primarily from sediments and atmospheric deposition. Septic systems, runoff, and fertilizers are lesser causes of the impairments. The TMDL document identifies two water body segments needing TMDLs for total nitrogen (Nantucket Harbor and Polpis Harbor). These water bodies are listed as impaired for nutrients on the Massachusetts’ 2008 Clean Water Act (CWA) §303(d) list. Nantucket Harbor and Polpis Harbor are identified as waterbody segment number MA97-01_2004 and MA97-26_2004, respectively. The TMDL document provides a good overview of the description and priority ranking of the water bodies, pollutants of concern and pollutant sources (pages 2-6). The companion Massachusetts Estuaries Project final report (November 2006) presents detailed information on the Nantucket Harbor Embayment System, Nantucket Island, and the Town of Nantucket. MassDEP has determined that all nutrient impaired segments in the Commonwealth are a high priority. See the Massachusetts 2008 Integrated List of Waters at: http://www.mass.gov/dep/water/resources/2008il1.pdf 2 Assessment: EPA New England concludes that the TMDL document meets the requirements for describing water body segment, pollutant of concern, identifying and characterizing sources of impairment, and priority ranking. 2. Description of the Applicable Water Quality Standards and Numeric Water Quality Target The TMDL submittal must include a description of the applicable State/Tribe water quality standard, including the designated use(s) of the waterbody, the applicable numeric or narrative water quality criterion, and the antidegradation policy. Such information is necessary for EPA’s review of the load and wasteload allocations which are required by regulation. A numeric water quality target for the TMDL (a quantitative value used to measure whether or not the applicable water quality standard is attained) must be identified. If the TMDL is based on a target other than a numeric water quality criterion, then a numeric expression, usually site specific, must be developed from a narrative criterion and a description of the process used to derive the target must be included in the submittal. The TMDL document identifies several provisions of the Commonwealth’s water quality standards that are relevant to the cultural eutrophication in these waters, including numeric criteria for dissolved oxygen and narrative criteria for nutrients, and aesthetics. As stated on page 8 of the TMDL document and in EPA guidance, individual estuarine and coastal marine waters tend to have unique characteristics and therefore, individual water body criteria are typically required. For example, the loading of nitrogen that a specific water body can handle without becoming impaired varies. Factors that influence the effect of nitrogen include: flow velocity, tidal hydraulics, dissolved oxygen, and sediment adsorption and desorption of nitrogen. The Massachusetts Estuaries Project analytical method is the Linked Watershed-Embayment Management Model (Linked Model) and is discussed on pages 8 - 14 of the TMDL document. It links watershed inputs with embayment circulation and nitrogen characteristics, and: • requires site-specific measurements within each watershed and embayment; • uses realistic “best-estimates” of nitrogen loads from each specific type of land-use; • spatially distributes the watershed nitrogen loading to the embayment; • accounts for nitrogen attenuation during transport to the embayment; • includes a 2D or 3D embayment circulation model depending on embayment structure; • accounts for basin structure, tidal variations, and dispersion within the embayment; • includes nitrogen regenerated within the embayment; • is validated by both independent hydrodynamic, nitrogen concentration, and ecological data; and • is calibrated and validated with field data prior to generation of “what if” scenarios. Sentinel locations were identified in the embayment system as locations at which restoration will necessarily result in high quality habitat throughout the system and attainment of water quality standards (page 12 and Appendix A, Figure A of the TMDL document). These sentinel locations 3 are located within the lower Head of the Harbor basin and in the eastern basin of Polpis Harbor and are based on eelgrass loss. Attaining the modeled nitrogen target at the sentinel locations through implementation of the TMDL will lead to restoration of eelgrass and infaunal habitats in each of the sub-embayments. The target threshold nitrogen concentrations which have been determined to be protective for each embayment system are 0.35 mg/L at the Head of the Harbor sentinel station and 0.36 mg/L at the Polpis Harbor sentinel station (Table 2, page 12 of the TMDL document). These concentrations, which represent the average water column concentrations of nitrogen, will restore or maintain high habitat quality in these embayments. Assessment: The use of the Linked Model, the description of the process in the TMDL document, and the companion Technical Report to this TMDL document adequately demonstrate the basis for deriving the target nitrogen loads and demonstrating that the targets will achieve water quality standards. EPA concludes that Massachusetts has properly presented its numeric water quality standards and has made a reasonable and appropriate interpretation of its narrative water quality criteria for the designated uses of the Nantucket Harbor embayment system. 3. Loading Capacity - Linking Water Quality and Pollutant Sources As described in EPA guidance, a TMDL identifies the loading capacity of a waterbody for a particular pollutant. EPA regulations define loading capacity as the greatest amount of loading that a water can receive without violating water quality standards (40 C.F.R. § 130.2(f) ). The loadings are required to be expressed as either mass- per-time, toxicity or other appropriate measure (40 C.F.R. § 130.2(i)). The TMDL submittal must identify the waterbody’s loading capacity for the applicable pollutant and describe the rationale for the method used to establish the cause-and-effect relationship between the numeric target and the identified pollutant sources. In most instances, this method will be a water quality model. Supporting documentation for the TMDL analysis must also be contained in the submittal, including the basis for assumptions, strengths and weaknesses in the analytical process, results from water quality modeling, etc. Such information is necessary for EPA’s review of the load and wasteload allocations which are required by regulation. In many circumstances, a critical condition must be described and related to physical conditions in the waterbody as part of the analysis of loading capacity (40 C.F.R. § 130.7(c)(1) ). The critical condition can be thought of as the “worst case” scenario of environmental conditions in the waterbody in which the loading expressed in the TMDL for the pollutant of concern will continue to meet water quality standards. Critical conditions are the combination of environmental factors (e.g., flow, temperature, etc.) that results in attaining and maintaining the water quality criterion and has an acceptably low frequency of occurrence. Critical conditions are important because they describe the factors that combine to cause a violation of water quality standards and will help in identifying the actions that may have to be undertaken to meet water quality standards. The Linked Model, as stated in the TMDL document is a robust and fairly complicated model that determines an embayment’s nitrogen sensitivity, nitrogen threshold loading levels (TMDL) and response to changes in the loading rate. A key feature of the approach involves the selection of sentinel sub-embayments that have the poorest water quality in the embayment system. If these degraded areas come into compliance with the TMDL, other areas will also achieve water quality standards for nitrogen in the system. This approach captures the critical targets needed to address the impaired segments. 4 The percent reductions of existing nitrogen loads necessary to meet the target thresholds are: 58% at Head of Harbor, 46% at Quaise Basin, 12% at Town Basin, and 38% at Polpis Harbor (page 15 of the TMDL document). These loads represent one scenario using the Linked Model. The TMDL loading capacity value for each sub-embayment represents the sum of the calculated target threshold load, atmospheric deposition load, and benthic flux load from sediment sources. For example at Head of Harbor, the TMDL is calculated by adding the target threshold load of 0.79 kg/day, the atmospheric load of 22.24 kg/day and the benthic input which is 0 kg/day. The TMDLs for Nantucket Harbor embayment system are 23 kg/day at Head of Harbor, 64 kg/day at Quaise Basin, 25 kg/day at Town Basin, and 31 kg/day at Polpis Harbor (page 19 and Appendix D of the TMDL document). See also Tables 4 and 5 below taken from MassDEP’s TMDL document. TABLE 4: Present Watershed Nitrogen Loading Rate, Target Threshold Nitrogen Loading Rate, and the Percent Reduction of the Existing Load Necessary to Achieve the Target Threshold Load (taken from page 15 of the TMDL document) Embayments Present Watershed Load 1 (kg/day) Target Threshold Watershed Load2 (kg/day) Percent Watershed Load Reductions Needed to Achieve Threshold Loads Head of Harbor 1.86 0.79 58 % Quaise Basin 2.12 1.14 46 % Town Basin 12.22 10.71 12 % Polpis Harbor 3.52 2.18 38 % 1 Composed of combined fertilizer, runoff, septic system loadings, and atmospheric deposition to freshwater lakes and natural surfaces 2 Target threshold watershed load is the load from the watershed needed to meet the target threshold N concentrations identified in Table 2 above 5 TABLE 5: The Total Maximum Daily Load (TMDL) for Nantucket Harbor Embayment System, Represented as the Sum of the Calculated Target Threshold Load (from Watershed Sources), Atmospheric Deposition, and Benthic Input (taken from page 19 of the TMDL document) Sub-embayment Target Threshold Watershed Load 1 (kg/day) Atmospheric Deposition (kg/day) Benthic Input (kg/day) TMDL 2 (kg/day) Head of Harbor 0.79 22.24 0 23 Quaise Basin 1.14 20.13 43.01 64 Town Basin 10.71 13.89 0 25 Polpis Harbor 2.18 2.19 26.45 31 1 Target threshold watershed load is the load from the watershed needed to meet the embayment threshold concentrations identified in Table 2 2 Sum of target threshold watershed load, atmospheric deposition load, and the benthic input load Assessment: The TMDL document explains and EPA concurs with the approach for applying the Linked Model to specific embayments for the purpose of developing target nitrogen loading rates and in identifying sources of needed nitrogen load reduction. EPA believes that this approach is reasonable because the factors influencing and controlling nutrient impairment were well justified. 4. Load Allocations (LAs) EPA regulations require that a TMDL include LAs, which identify the portion of the loading capacity allocated to existing and future nonpoint sources and to natural background (40 C.F.R. § 130.2(g) ). Load allocations may range from reasonably accurate estimates to gross allotments (40 C.F.R. § 130.2(g) ). Where it is possible to separate natural background from nonpoint sources, load allocations should be described separately for background and for nonpoint sources. If the TMDL concludes that there are no nonpoint sources and/or natural background, or the TMDL recommends a zero load allocation, the LA must be expressed as zero. If the TMDL recommends a zero LA after considering all pollutant sources, there must be a discussion of the reasoning behind this decision, since a zero LA implies an allocation only to point sources will result in attainment of the applicable water quality standard, and all nonpoint and background sources will be removed. Using the Linked Model, Mass DEP has identified the portion of the loading capacity allocated to existing and future non-point sources necessary to meet water quality standards. These non- point sources are primarily on-site subsurface wastewater disposal systems (i.e. septic systems), runoff (stormwater) and fertilizer. Because there are no NPDES-regulated sources and there is 6 an implicit Margin of Safety (see Section 6 below), the LA in this TMDL is equal to the TMDL loading capacity in Section 3 above [TMDL (loading capacity) = LA + WLA + MOS; where the WLA and MOS are respectively zero and implicit in this case]. Assessment: EPA concludes that the TMDL document sufficiently addresses the calculation of the load allocations. 5. Wasteload Allocations (WLAs) EPA regulations require that a TMDL include WLAs, which identify the portion of the loading capacity allocated to existing and future point sources (40 C.F.R. § 130.2(h)). If no point sources are present or if the TMDL recommends a zero WLA for point sources, the WLA must be expressed as zero. If the TMDL recommends a zero WLA after considering all pollutant sources, there must be a discussion of the reasoning behind this decision, since a zero WLA implies an allocation only to nonpoint sources and background will result in attainment of the applicable water quality standard, and all point sources will be removed. In preparing the wasteload allocations, it is not necessary that each individual point source be assigned a portion of the allocation of pollutant loading capacity. When the source is a minor discharger of the pollutant of concern or if the source is contained within an aggregated general permit, an aggregated WLA can be assigned to the group of facilities. But it is necessary to allocate the loading capacity among individual point sources as necessary to meet the water quality standard. The TMDL submittal should also discuss whether a point source is given a less stringent wasteload allocation based on an assumption that nonpoint source load reductions will occur. In such cases, the State/Tribe will need to demonstrate reasonable assurance that the nonpoint source reductions will occur within a reasonable time. As discussed in Section 4 above, there are no NPDES-regulated sources in the watershed, therefore, the WLA which is the load from NPDES permit regulated discharges (CWA point sources) is zero. MassDEP has provided, for informational purposes, an estimated (non-CWA) “WLA” in Appendix C of the TMDL document based on the impervious cover in each sub- embayment. Appendix C illustrates the relative amount of impervious cover and associated stormwater runoff between the sub-embayments. Assessment: EPA concludes that the TMDL document sufficiently addresses the determination of the waste load allocation which is zero in this TMDL because there are no NPDES regulated point sources. 6. Margin of Safety (MOS) The statute and regulations require that a TMDL include a margin of safety to account for any lack of knowledge concerning the relationship between load and wasteload allocations and water quality (CWA § 303(d)(1)(C), 40 C.F.R. § 130.7(c)(1) ). EPA guidance explains that the MOS may be implicit, i.e., incorporated into the TMDL through conservative assumptions in the analysis, or explicit, i.e., expressed in the TMDL as loadings set aside for the MOS. If the MOS is implicit, the conservative assumptions in the analysis that account for the MOS must be described. If the MOS is explicit, the loading set aside for the MOS must be identified. 7 The implicit margin of safety is set out in the TMDL document on pages 17 - 18. There are several factors that contribute to the margin of safety inherent in the approach used to develop this TMDL including: 1) Use of conservative data in the Linked Model as follows: • Nitrogen concentrations in the watershed that were used in the model were higher and more conservative than those actually measured in the streams; • Agreement between the modeled and observed values has been approximately 95%; • Attenuation factors used were lower and more conservative than those that were actually measured; • Lawn fertilization rates were based on actual survey. These rates represent a conservative estimate of the nitrogen load; • Loading calculations assumed that 90% of water used is converted to wastewater, which is a conservative assumption; and • Loading calculations for homes that do not have metered water use were made conservatively; 2) Conservative sentinel station/target threshold nitrogen concentrations Sites were chosen that had stable eelgrass or benthic (infaunal) communities. Selection of sites that were starting to show impairment would have resulted in higher nitrogen concentrations; and 3) Conservative approach Target loads were based on averaged nitrogen concentrations on the outgoing tide. This is the worst case scenario because this is when the nitrogen concentrations are highest. Nitrogen concentrations will be lower on the flood tides, due to dilution from the incoming tide. Assessment: EPA concludes that the implicit margin of safety for the TMDL is acceptable. 7. Seasonal Variation The statute and regulations require that a TMDL be established with consideration of seasonal variations. The method chosen for including seasonal variations in the TMDL must be described (CWA § 303(d)(1)(C), 40 C.F.R. § 130.7(c)(1)). The TMDL for the water body segment identified in the document are based on achieving the nitrogen loads during the most critical time period, i.e., the summer growing season. Since the other seasons are less sensitive to nitrogen loading, the TMDL is protective of all seasons throughout the year. Seasonal variation is addressed on page 19 of the TMDL document. Assessment: 8 Since the other seasons are less sensitive to nitrogen loading, EPA concludes that the TMDL is protective of all seasons throughout the year. 8. Monitoring Plan for TMDLs Developed Under the Phased Approach EPA’s 1991 document, Guidance for Water Quality-Based Decisions: The TMDL Process (EPA 440/4-91-001), and EPA’s 2006 guidance, Clarification Regarding “Phased” Total Maximum Daily Loads, recommend a monitoring plan when a TMDL is developed using the phased approach. The guidance indicates that a State may use the phased approach for situations where TMDLs need to be developed despite significant data uncertainty and where the State expects that the loading capacity and allocation scheme will be revised in the near future. EPA’s guidance provides that a TMDL developed under the phased approach should include, in addition to the other TMDL elements, a monitoring plan that describes the additional data to be collected and a scheduled timeframe for revision of the TMDL. Because this TMDL is not a “phased” TMDL, a monitoring plan is not required in order to assure that data is available for updating the TMDL in the near future. Nevertheless, in order to assess the progress in obtaining the TMDLs’ water quality goals, MassDEP has recommended that the Town of Nantucket track implementation progress as approved in the Town Comprehensive Wastewater Management Planning (CWMP) and monitor ambient water quality conditions at the sentinel stations (pages 21-22 of the TMDL document). MassDEP presents suggested guidelines for water quality, benthic habitat and community, and eelgrass bed monitoring. Assessment: EPA New England concludes that the anticipated monitoring by and in cooperation with MassDEP is sufficient to evaluate the adequacy of the TMDL and attainment of water quality standards, although not a required element for TMDL approval. 9. Implementation Plans On August 8, 1997, Bob Perciasepe (EPA Assistant Administrator for the Office of Water) issued a memorandum, “New Policies for Establishing and Implementing Total Maximum Daily Loads (TMDLs),” that directs Regions to work in partnership with States/Tribes to achieve nonpoint source load allocations established for 303(d)-listed waters impaired solely or primarily by nonpoint sources. To this end, the memorandum asks that Regions assist States/Tribes in developing implementation plans that include reasonable assurances that the nonpoint source load allocations established in TMDLs for waters impaired solely or primarily by nonpoint sources will in fact be achieved. The memorandum also includes a discussion of renewed focus on the public participation process and recognition of other relevant watershed management processes used in the TMDL process. Although implementation plans are not approved by EPA, they help establish the basis for EPA’s approval of TMDLs. The implementation plan for the total nitrogen TMDL for the Nantucket Harbor Embayment System is described on pages 20 and 21 of the TMDL document. EPA concludes that the approach taken by MassDEP is reasonable because of the resources available to the towns to address nitrogen, such as the CWMP, additional linked model runs at nominal expense, assessment of cost-effective options for reducing loadings from individual on-site subsurface wastewater disposal systems, land use planning and controls, water conservation, and stormwater control and treatment. MassDEP advised the town to incorporate the nitrogen loading reduction 9 strategies outlined in the Massachusetts Estuaries Implementation Guidance report http://www.mass.gov/dep/water/resources/restore.htm into the implementation plan. Assessment: MassDEP has addressed the implementation plan, although it is not required. EPA is taking no action on the implementation plan. 10. Reasonable Assurances EPA guidance calls for reasonable assurances when TMDLs are developed for waters impaired by both point and nonpoint sources. In a water impaired by both point and nonpoint sources, where a point source is given a less stringent wasteload allocation based on an assumption that nonpoint source load reductions will occur, reasonable assurance that the nonpoint source reductions will happen must be explained in order for the TMDL to be approvable. This information is necessary for EPA to determine that the load and wasteload allocations will achieve water quality standards. In a water impaired solely by nonpoint sources, reasonable assurances that load reductions will be achieved are not required in order for a TMDL to be approvable. However, for such nonpoint source-only waters, States/Tribes are strongly encouraged to provide reasonable assurances regarding achievement of load allocations in the implementation plans described in section 9, above. As described in the August 8, 1997 Perciasepe memorandum, such reasonable assurances should be included in State/Tribe implementation plans and “may be non-regulatory, regulatory, or incentive-based, consistent with applicable laws and programs.” The Commonwealth has statutory and regulatory authority to encourage implementation of this TMDL. Nitrogen loading reductions are currently being required through a consent decree and the CWMP. In addition, Nantucket has demonstrated its commitment to implement this TMDL through the comprehensive wastewater planning that they initiated well before the generation of this TMDL. The town expects to use the information in this TMDL to generate support from their citizens to take the necessary steps to remedy existing problems related to nitrogen loading from septic systems, stormwater, and runoff (including fertilizers), and to prevent any future degradation of these valuable resources. Enforcement of local, state, and federal programs for pollution control contribute to the level of reasonable assurance. There are also financial incentives to encourage the community to follow through with its plans and prevent further degradation to water quality. Assessment: Reasonable assurance is not necessary for this TMDL to be approvable, since the point sources are not given less stringent wasteload allocations based on projected nonpoint source load reductions. MassDEP has provided reasonable assurance that water quality standards will be met. 10 11. Public Participation EPA policy is that there must be full and meaningful public participation in the TMDL development process. Each State/Tribe must, therefore, provide for public participation consistent with its own continuing planning process and public participation requirements (40 C.F.R. § 130.7(c)(1)(ii) ). In guidance, EPA has explained that final TMDLs submitted to EPA for review and approval must describe the State/Tribe’s public participation process, including a summary of significant comments and the State/Tribe’s responses to those comments. When EPA establishes a TMDL, EPA regulations require EPA to publish a notice seeking public comment (40 C.F.R. § 130.7(d)(2) ). Inadequate public participation could be a basis for disapproving a TMDL; however, where EPA determines that a State/Tribe has not provided adequate public participation, EPA may defer its approval action until adequate public participation has been provided for, either by the State/Tribe or by EPA. MassDEP publicly announced the draft TMDL on September 25, 2007 and copies were distributed to all key stakeholders. The draft TMDL was also posted on the Department’s web site for public review on that date. A public meeting was held at the Town of Nantucket, Veteran’s Community Center on October 9, 2007 for information and solicitation of comments. The public comment period was extended until November 2, 2007. MassDEP submitted a response to comments to EPA along with the final submission on February 3, 2009. Assessment: EPA concludes that MassDEP has involved the public during the development of the TMDL, has provided adequate opportunities for the public to comment on the TMDL, and has provided reasonable responses to the public comments. 12. Submittal Letter A submittal letter should be included with the TMDL analytical document, and should specify whether the TMDL is being submitted for a technical review or is a final submittal. Each final TMDL submitted to EPA must be accompanied by a submittal letter that explicitly states that the submittal is a final TMDL submitted under Section 303(d) of the Clean Water Act for EPA review and approval. This clearly establishes the State/Tribe’s intent to submit, and EPA’s duty to review, the TMDL under the statute. The submittal letter, whether for technical review or final submittal, should contain such information as the name and location of the waterbody, the pollutant(s) of concern, and the priority ranking of the waterbody. On February 3, 2009, MassDEP submitted a final TMDL for total nitrogen in the Nantucket Harbor Embayment System for EPA approval. The final TMDL contained revisions based upon public comments. The TMDL document contained all of the elements necessary to approve the TMDL. Assessment: MassDEP’s letter of February 3, 2009 states that the TMDL is being formally submitted for EPA review and approval. 11 Attachment 1 2 Total Nitrogen TMDLs Embayment Description Sub-Embayment TMDL (kg/day) Nantucket Harbor Determined to be impaired for Head of Harbor 23 Water Body Segment # nutrients, pathogens, and noxious Quaise Basin 64 MA97-01_2004 aquatic plants by MassDEP. Town Basin 25 Polpis Harbor Water Body Segment # MA97-26_2004 Determined to be impaired for nutrients, other habitat alterations, and pathogens by MassDEP. 31 12 Data for entry in EPA’s National TMDL Tracking System TMDL Name * Nantucket Harbor Bay System Number of TMDLs* 2 Type of TMDLs* Nutrients (Nitrogen) Number of listed causes (from 303(d) list) 2 Information/prevention TMDLs, Y/N? (#) No Lead State Massachusetts TMDL Status Final Individual TMDLs listed below TMDL sub-embayments systems and segment names TMDL Segment ID # TMDL Pollutant ID# & name TMDL Impairment Cause(s) Pollutant endpoint Unlisted? NPDES Point Source & ID# Listed for something else? Nantucket Harbor: Head of Harbor [See note below] MA97-01_2004 511 (total nitrogen) Nutrients 0.35 mg/L Total Nitrogen No Yes Pathogens, noxious aquatic plants Polpis Harbor MA97-26_2004 511 (total nitrogen) Nutrients 0.36 mg/L Total Nitrogen No Yes Pathogens, Other habitat alterations TMDL Type Nonpoint Source (Stormwater) Establishment Date (approval)* May 12, 2009 EPA Developed No Towns affected* Nantucket Note: Nantucket Harbor has 3 sentinel locations within one segment for purposes of the TMDL: Head of Harbor, Quaise Basin, and Town Basin DRAFT Madaket and Long Pond Estuarine System Total Maximum Daily Loads For Total Nitrogen (Report # 97-TMDL-5 Control # 283.0) COMMONWEALTH OF MASSACHUSETTS EXECUTIVE OFFICE OF ENERGY AND ENVIRONMENTAL AFFAIRS RICHARD K. SULLIVAN, SECRETARY MASSACHUSETTS DEPARTMENT OF ENVIRONMENTAL PROTECTION KENNETH L. KIMMELL, COMMISSIONER BUREAU OF RESOURCE PROTECTION ANN LOWERY, DEPUTY ASSISTANT COMMISSIONER August 2011 Madaket Harbor Long Pond Upper Long Pond Middle Long Pond Lower Hither Creek Nantucket Sound Atlantic Ocean 2 Madaket Harbor and Long Pond Estuarine System Total Maximum Daily Loads For Total Nitrogen Key Feature:Total Nitrogen TMDLs for Madaket Harbor and Long Pond Estuarine System Location:EPA Region 1 Land Type:New England Coastal 303d Listing:The water body segments impaired and on the Category 5 list include Hither Creek, Long Pond and Madaket Harbor. Data Sources:University of Massachusetts – Dartmouth/School for Marine Science and Technology; US Geological Survey; Applied Coastal Research and Engineering, Inc.; Town of Nantucket Data Mechanism:Massachusetts Surface Water Quality Standards, Ambient Data, and Linked Watershed Model Monitoring Plan:Town of Nantucket monitoring program (technical assistance from SMAST) Control Measures:Sewering, Storm Water Management, Attenuation by Impoundments and Wetlands, Fertilizer Use By-laws, Landfill Management Madaket Harbor and Long Pond 3 Executive Summary Problem Statement Excessive nitrogen (N) originating from a range of sources has added to the impairment of the environmental quality of the Madaket Harbor and Long Pond Estuarine System. Excessive N is indicated by: Undesirable increases in macro algae Periodic extreme decreases in dissolved oxygen concentrations that threaten aquatic life Reductions in the diversity of benthic animal populations Periodic algae blooms With proper management of N inputs these trends can be reversed. Without proper management more severe problems might develop, including: Periodic fish kills Unpleasant odors and scum Benthic communities reduced to the most stress-tolerant species, or in the worst cases, near loss of the benthic animal communities Coastal communities rely on clean, productive, and aesthetically pleasing marine and estuarine waters for tourism, recreational swimming, fishing, and boating, as well as for commercial fin fishing and shellfishing. Failure to reduce and control N loadings could result in an overabundance of macro-algae, a higher frequency of extreme decreases in dissolved oxygen concentrations and fish kills, widespread occurrence of unpleasant odors and visible scum, and a complete loss of benthic macroinvertebrates throughout most of the embayments. As a result of these environmental impacts, commercial and recreational uses of the Madaket Harbor and Long Pond Estuarine System will be greatly reduced. Sources of Nitrogen Nitrogen enters the waters of coastal embayments from the following sources: The watershed Natural background Septic Systems Runoff Fertilizers Wastewater treatment facilities Atmospheric deposition Nutrient-rich bottom sediments in the embayments Figure ES-A and Figure ES-B illustrate the percent contribution of all the sources of N and the controllable N sources to the estuary system, respectfully. Values are based on Table IV-2 and Figure IV-6 from the Massachusetts Estuaries Project (MEP) Technical Report. As evident, most of the present controllable load to this system comes from septic systems. 4 Figure ES-A: Percent Contributions of All Nitrogen Sources to the Madaket Harbor and Long Pond Estuarine System Figure ES-B: Percent Contributions of Controllable Nitrogen Sources to the Madaket Harbor and Long Pond Estuarine System 5 Target Threshold N Concentrations and Loadings The N loadings (the quantity of N) to this system ranged from 9.27 kg/day in Madaket Harbor to 4.58 kg/day in Hither Creek, and 5.14 kg/day in Long Pond with total loads for the Madaket Harbor and Long Pond Estuarine System of 21.41 kg N/day (as reported in Table IV-2 of the MEP Technical Report). The resultant concentrations of N ranged from 0.336-0.422 mg/L in Madaket Harbor, 0.581-0.780 mg/L in Hither Creek and 0.894 – 1.058 mg/L in Long Pond (range of average annual means collected from 13 stations during 2002-2004 as reported in Table VI-1 of the MEP Technical Report, and included in Appendix A of this report). In order to restore and protect this estuarine system, N loadings, and subsequently the concentrations of N in the water, must be reduced to levels below those that cause the observed environmental impacts. This N concentration will be referred to as the target threshold N concentration. The Massachusetts Estuaries Project (MEP) has determined that by achieving a N concentration of 0.45 mg/Lnear sentinel station M11 in Hither Creek, water and habitat quality will be restored in these systems. The mechanism for achieving the target threshold N concentrations is to reduce the N loadings to the watershed of the harbor estuarine system. Based on the MEP sampling and modeling analyses and their Technical Report, the MEP study has determined that the Total Maximum Daily Loads (TMDL) of N that will meet the target threshold N concentration of 0.45 mg/L range from 1.67 kg/day in the Hither Creek subwatershed to 27.218 kg/day in the Madaket Harbor subwatershed. To meet these TMDLs this report recommends a reduction of 100% of the septic load for the Hither Creek subwatershed and assumes that the landfill load will be eliminated by completing the ongoing mining and capping project being conducted by the town. This document presents the TMDLs for these water body systems and provides guidance to the watershed community of Nantucket on possible ways to reduce the N loadings to within the recommended TMDL and protect the waters of these embayment systems. Implementation The primary goal of TMDL implementation will be lowering the concentrations of N by reducing the loadings from on-site subsurface wastewater disposal systems by 100% in the Hither Creek subwatershed. However, there is a variety of loading reduction scenarios that could achieve the target threshold N concentrations. Local officials can explore other loading reduction scenarios through additional modeling as part of their Comprehensive Wastewater Management Plan (CWMP). In addition, the Town of Nantucket is currently involved in an implementation process to reduce the landfill contribution to the nitrogen load of Long Pond. It is expected that the landfill nitrogen loads will likely be eliminated after completion of this project and these TMDLs are calculated based on that assumption. Implementing best management practices (BMPs) to reduce N loadings from fertilizers and runoff where possible will also help to lower the total N load to these systems. Methods for reducing N loadings from these sources are explained in detail in the “MEP Embayment Restoration Guidance for Implementation Strategies” that is available on the MassDEP website http://www.mass.gov/dep/water/resources/coastalr.htm#guidance. The appropriateness of any of the alternatives will depend on local conditions and will have to be determined on a case-by-case basis using an adaptive management approach. 6 Table of Contents Executive Summary................................................................................................................................................ 3 Table of Contents.................................................................................................................................................... 6 List of Figures......................................................................................................................................................... 6 List of Tables .......................................................................................................................................................... 7 Introduction............................................................................................................................................................. 8 Description of Water Bodies and Priority Ranking................................................................................................ 9 Problem Assessment............................................................................................................................................. 13 Pollutant of Concern, Sources, and Controllability.............................................................................................. 14 Description of the Applicable Water Quality Standards....................................................................................... 17 Methodology - Linking Water Quality and Pollutant Sources ............................................................................. 17 Application of the Linked Watershed-Embayment Model................................................................................... 19 Total Maximum Daily Loads................................................................................................................................ 24 TMDL Values for the Madaket Harbor and Long Pond Estuarine System.......................................................... 29 Implementation Plans............................................................................................................................................ 29 Monitoring Plan.................................................................................................................................................... 31 Reasonable Assurances......................................................................................................................................... 31 Appendix A: Summary of the Nitrogen Concentrations for Madaket Harbor/Long Pond Estuarine System...... 33 Appendix B: Madaket Harbor/ Long Pond Estuarine System Five Total Nitrogen TMDLs ............................... 34 List of Figures Figure ES-A: Percent Contributions of All Nitrogen Sources to the Madaket Harbor and Long Pond Estuarine System..................................................................................................................................................................... 4 Figure ES-B: Percent Contributions of Controllable Nitrogen Sources to the Madaket Harbor and Long Pond Estuarine System..................................................................................................................................................... 4 Figure 1: Watershed Delineations for the Madaket Harbor and Long Pond Estuarine System ........................... 11 Figure 2: Map of the Madaket Harbor and Long Pond Estuarine System............................................................ 12 Figure 3: Resident Population for Nantucket........................................................................................................ 13 Figure 4a: Percent Contribution of Nitrogen Sources to the Madaket Harbor..................................................... 16 and Long Pond Estuarine System......................................................................................................................... 16 Figure 4b: Percent Contributions of Controllable Nitrogen Sources to the.......................................................... 16 Madaket Harbor and Long Pond Estuarine System.............................................................................................. 16 Figure 5: Water Quality Sampling Stations in the Madaket Harbor and Long Pond Estuarine System .............. 20 Figure 6: Madaket Harbor and Long Pond Estuarine System Locally Controllable N Sources........................... 26 7 List of Tables Table 1. Nantucket MEP Study Waterbodies in Category 5 of the MA 2008 Integrated List ....................... 9 Table 2: Comparison of Impaired Parameters for the Nantucket Segments................................................. 10 Table 3: General Summary of Conditions Related to the Major Indicators of Habitat Impairment Observed in the Madaket Harbor and Long Pond Estuarine System............................................................................ 14 Table 4: Present Nitrogen Concentrations and Sentinel Station Target Threshold Nitrogen Concentrations for the Madaket Harbor and Long Pond Estuarine System .......................................................................... 20 Table 5: Present Nitrogen Loadings to the Madaket Harbor and Long Pond Estuarine System................. 23 Table 6: Present Watershed Nitrogen Loading Rates, Calculated Loading Rates that are Necessary to Achieve Target Threshold Nitrogen Concentrations, and the Percent Reductions of the Existing Loads Necessary to Achieve the Target Threshold Loadings................................................................................. 24 Table 7: The Total Maximum Daily Loads (TMDL) for the Madaket Harbor and Long Pond Estuarine System, Represented as the Sum of the Calculated Target Threshold Loads, Atmospheric Deposition and Sediment Load.............................................................................................................................................. 29 8 Introduction Section 303(d) of the Federal Clean Water Act requires each state to identify waters that are not meeting water quality standards and to establish Total Maximum Daily Loads (TMDLs) for such waters for the pollutants of concern. The TMDL allocation establishes the maximum loadings (of pollutants of concern) from all contributing sources that a water body may receive and still meet and maintain its water quality standards and designated uses, including compliance with numeric and narrative standards. The TMDL development process may be described in four steps, as follows: 1. Determination and documentation of whether or not a water body is presently meeting its water quality standards and designated uses. 2. Assessment of present water quality conditions in the water body, including estimation of present loadings of pollutants of concern from both point sources (discernable, confined, and concrete sources such as pipes) and non-point sources (diffuse sources that carry pollutants to surface waters through runoff or groundwater). 3. Determination of the loading capacity of the water body. EPA regulations define the loading capacity as the greatest amount of loading that a water body can receive without violating water quality standards. If the water body is not presently meeting its designated uses, then the loading capacity will represent a reduction relative to present loadings. 4. Specification of load allocations, based on the loading capacity determination, for non-point sources and point sources that will ensure that the water body will not violate water quality standards. After public comment and final approval by the EPA, the TMDL will serve as a guide for future implementation activities. The MassDEP will work with the watershed town of Nantucket to develop specific implementation strategies to reduce N loadings, and will assist in developing a monitoring plan for assessing the success of the nutrient reduction strategies. In the Madaket Harbor and Long Pond Estuarine System the pollutant of concern for these TMDLs (based on observations of eutrophication) is the nutrient nitrogen. Nitrogen is the limiting nutrient in coastal and marine waters, which means that as its concentration is increased so is the amount of plant matter. This leads to nuisance populations of macro-algae and increased concentrations of phytoplankton and epiphyton which impairs the healthy ecology of the affected water bodies. The TMDLs for total N for the Madaket Harbor and Long Pond Estuarine System are based primarily on data collected, compiled and analyzed by University of Massachusetts Dartmouth’s School of Marine Science and Technology (SMAST) Coastal Systems Program and the Town of Nantucket Marine Department as part of the Massachusetts Estuaries Project (MEP). The data were collected over a study period from 2001 through 2007. This study period will be referred to as the “present conditions” in the TMDL report since it contains the most recent data available. The accompanying MEP Technical Report can be found at http://www.oceanscience.net/estuaries/reports.htm. The MEP Technical Report presents the results of the analyses of the coastal embayment systems using the MEP Linked Watershed-Embayment N Management Model (Linked Model). The analyses were performed to assist the watershed community with decisions on current and future wastewater planning, wetland restoration, anadromous fish runs, shellfisheries, open-space and harbor maintenance programs. A critical element of this approach is the assessment of water quality monitoring data, historical changes in eelgrass distribution, time-series water column oxygen measurements and benthic community structure that was conducted on this embayment. These assessments served as the basis for generating a N loading threshold for use as a goal for watershed N management. The TMDLs are based on the site specific N threshold generated for this estuarine system. Thus, the MEP offers a science-based 9 management approach to support the wastewater management planning and decision-making process in the watershed community of Nantucket. Description of Water Bodies and Priority Ranking The Madaket Harbor and Long Pond Estuarine System is located entirely within the Town of Nantucket making Nantucket the sole municipal steward of this system (see Figures 1 and 2). The estuarine system is located at the western end of Nantucket Island. Madaket Harbor is an open-water, well flushed shallow basin with its western boundary generally open to Nantucket Sound and the Atlantic Ocean. A dynamic network of sand shoals along the harbor boundary may restrict circulation somewhat. The southern boundary of the Harbor is defined by a long sand spit that periodically is breached to the Atlantic Ocean and the northern shore is defined by Eel Point. The only surface water tributary to Madaket Harbor is Hither Creek, which is connected to brackish Long Pond via Madaket Ditch. Hither Creek is an artificially deepened basin that opens into Madaket Harbor, Madaket Ditch is a shallow, narrow ditch and inland Long Pond is brackish and shallow. This tributary component obtains freshwater inflow primarily via groundwater contributions due to the highly permeable nature of the watershed soils. Compared to the harbor, circulation and flushing are limited, especially within Long Pond. Long Pond was divided into a northern, middle and lower section in the MEP study. This estuarine system constitutes an important component of the area’s natural and cultural resources. The nature of enclosed embayments in populous regions brings two opposing elements to bear: 1) as protected marine shoreline, they are popular regions for boating, recreation, and land development; and 2) as enclosed bodies of water, they may not be readily flushed of the pollutants that they receive due to the proximity and density of development near and along their shores. In particular, the Madaket Harbor and Long Pond Estuarine system are at risk of further eutrophication from high nutrient loads in the groundwater and runoff from their watersheds. Hither Creek and Long Pond are already listed as impaired for nutrients and requiring a TMDL (Category 5) in the MA 2008 Integrated List of Waters, as summarized in Table 1. Madaket Harbor and Long Pond are listed as impaired for pathogens and are included in Table 1 for completeness. Further discussion of pathogens is beyond the scope of this TMDL. Table 1. Nantucket MEP Study Waterbodies in Category 5 of the MA 2008 Integrated List (MassDEP 2008) Name Water Body Segment Description Size Pollutant Listed Hither Creek (9764000)MA97-28_2008 From the outlet of Madaket Ditch to Madaket Harbor at an imaginary line drawn easterly from Jackson Point to Little Neck, Nantucket 0.07 sq mi -Nutrients -Organic enrichment/Low DO Long Pond (97050) MA97-29_2008 South of Madaket Road, including White Goose Cove, Nantucket 0.12 sq mi -Nutrients -Organic enrichment/Low DO -Pathogens -Turbidity Madaket Harbor (97910)MA97-27_2008 Waters encompassed within imaginary lines from Eel Point to the northern tip of Esther Island, from the southern tip of Esther Island southeasterly to the opposite shore and from Jackson Point easterly to Little Neck, Nantucket 1.4 sq mi -Pathogens 10 Complete descriptions of these embayment systems are presented in Chapters I and IV of the MEP Technical Report. A majority of the information presented here is drawn from this report. Chapters VI and VII of the MEP Technical Report provide assessment data that show that the Madaket Harbor and Long Pond Estuarine System is impaired because of nutrients, low dissolved oxygen levels, elevated chlorophyll a levels, and benthic fauna habitat. Table 2 identifies the segments previously listed in Category 5 of the Integrated List of Waters by MassDEP and the segments that were observed to be impaired through the MEP analysis. The embayments addressed by this document have been determined to be “high priority” based on three significant factors: (1) the initiative that the Town of Nantucket has taken to assess the conditions of the entire embayment system; (2) the commitment made by the town to restore the Madaket Harbor and Long Pond; and (3) the extent of impairment in the Madaket Harbor and Long Pond Estuarine System. In both marine and freshwater systems, an excess of nutrients results in degraded water quality, adverse impacts to ecosystems and limits on the use of water resources. Observations are summarized in the Problem Assessment section below and detailed in Chapter VII, Assessment of Embayment Nutrient Related Ecological Health, of the MEP Technical Report. Table 2: Comparison of Impaired Parameters for the Nantucket Segments Name DEP Listed Impaired Parameter SMAST Listed Impaired Parameter Madaket Harbor - Pathogens -Nutrients Hither Creek -Nutrients -Organic enrichment/Low DO -Nutrients -DO level -Chlorophyll -Benthic fauna Long Pond -Nutrients -Organic enrichment/Low DO -Pathogens -Turbidity -Nutrients -DO level -Chlorophyll -Benthic fauna 11 Figure 1: Watershed Delineations for the Madaket Harbor and Long Pond Estuarine System 12 Figure 2: Map of the Madaket Harbor and Long Pond Estuarine System (from United States Geological Survey topographic maps). 13 Problem Assessment Water quality problems associated with development within the watershed result primarily from septic systems and from runoff, including fertilizers. The water quality problems affecting nutrient-enriched embayments generally include periodic decreases of dissolved oxygen, decreased diversity and quantity of benthic animals and periodic algae blooms. In the most severe cases habitat degradation could lead to periodic fish kills, unpleasant odors and scums and near loss of the benthic community and/or presence of only the most stress-tolerant species of benthic animals. Coastal communities, including Nantucket, rely on clean, productive and aesthetically pleasing marine and estuarine waters for tourism, recreational swimming, fishing and boating, as well as commercial fin fishing and shell fishing. The continued degradation of this coastal embayment, as described above, will significantly reduce the recreational and commercial value and use of these important environmental resources. Figure 3 shows how the population of Nantucket has more than doubled from less than 4,000 people in 1930 to over 9,500 people in 2000. Increases in N loading to estuaries are directly related to increasing development and population in the watershed. The Town of Nantucket has been among the fastest growing towns in the Commonwealth over the past two decades. This increase in population contributes to a decrease in undeveloped land and an increase in septic systems, runoff from impervious surfaces and fertilizer use. Although the Nantucket downtown area is serviced by a centralized wastewater treatment facility, all the residences in the Madaket Harbor and Long Pond watershed are serviced by septic systems. The greatest level of development and residential load is situated in the nearshore regions of the system. These unsewered areas contribute significantly to the system through transport in direct groundwater discharges to estuarine waters and through surface water flows from Long Pond to Madaket Ditch and Hither Creek. Figure 3: Resident Population for Nantucket Habitat and water quality assessments were conducted on this estuarine system based upon water quality monitoring data, changes in eelgrass distribution, time-series water column oxygen measurements and benthic community structure. The MEP evaluation of habitat quality supported by each area considers its natural structure and its ability to support eelgrass beds and the types of infaunal communities that they support (Table 3). At present, Madaket Harbor and particularly Hither Creek and Long Pond appear to have reached their nitrogen loading thresholds. This is demonstrated by the existing low habitat and water quality of Hither Creek (loss of eelgrass) and Long Pond. Although large portions of Madaket Harbor still support eelgrass, the slight 14 decline of eelgrass in certain areas suggests a degree of impairment. Consistent with a system at its nitrogen threshold for eelgrass habitat, most of the Harbor is currently supporting productive benthic animal communities, oxygen is not depleted, chlorophyll a levels are low and macroalgae is sparse. In contrast Hither Creek is nitrogen enriched with a tidally averaged TN concentration of 0.51 mg N/l compared to 0.33 mg N/l seen in Madaket Harbor. This results in high chlorophyll a, periodic hypoxia, and complete loss of eelgrass, dense macroalgae and impaired benthic communities. Long Pond is also nitrogen enriched, however due to the influence of natural wetland systems the level of impairment is moderate as demonstrated by high chlorophyll a levels and periodic blooms, and somewhat altered benthic community structure. There is no evidence that eelgrass habitat existed previously in the Long Pond basins so absence does not indicate impairment of this habitat. Table 3: General Summary of Conditions Related to the Major Indicators of Habitat Impairment Observed in the Madaket Harbor and Long Pond Estuarine System Health Indicator Madaket Harbor Estuarine System Madaket Harbor Hither Creek Long Pond Mid Lower North Head Dissolved Oxygen H SI MI/SI MI H Chlorophyll H MI/SI SI MI/SI H/MI Macroalgae H SI --- Eelgrass H SI ------ Infaunal Animals H SI MI MI H/MI Overall H SI MI MI H/MI H - Healthy Habitat Conditions* MI – Moderately Impaired* SI – Significantly Impaired- considerably and appreciably changed from normal conditions* * - These terms are more fully described in MEP report “Site-Specific Nitrogen Thresholds for Southeastern Massachusetts Embayments: Critical Indicators” December 22, 2003 http://www.mass.gov/dep/water/resources/nitroest.pdf -drift algae sparse or absent --no evidence this basin is supportive of eelgrass Pollutant of Concern, Sources, and Controllability In the coastal embayments of the Town of Nantucket, as in most marine and coastal waters, the limiting nutrient is N. Nitrogen concentrations beyond those expected naturally contribute to undesirable conditions including the severe impacts described above, through the promotion of excessive growth of plants and algae, including nuisance vegetation. The embayments addressed in this TMDL report have had extensive data collected and analyzed through the Massachusetts Estuaries Program (MEP) and with the cooperation and assistance from the Town of Nantucket, 15 the USGS, and the Cape Cod Commission. Data collection included both water quality and hydrodynamics as described in Chapters I, IV, V, and VII of the MEP Technical Report. Figure 4a illustrates all of the sources of N to the Madaket Harbor and Long Pond Estuarine System and Figure 4b shows just the controllable sources. As evident, most of the controllable N affecting these systems originates from on-site subsurface wastewater disposal systems (septic systems). The level of “controllability” of each source, however, varies widely: Atmospheric deposition– Although helpful, local controls are not adequate – it is only through region- and nation-wide air pollution control initiatives that significant reductions are feasible, however the N from these sources might be subjected to enhanced natural attenuation as it moves towards the estuary. Fertilizer –Fertilizer and related N loadings can be reduced through best management practices (BMPs), bylaws and public education. Impervious surfaces and storm-water runoff sources of N can be controlled by BMPs, bylaws and storm-water infrastructure improvements and public education; Septic system sources of N can be controlled by a variety of case-specific methods including: sewering and treatment at centralized or decentralized locations, transporting and treating septage at treatment facilities with N removal technology either in or out of the watershed, or installing N-reducing on-site wastewater treatment systems. Landfill – the Town of Nantucket operates a landfill adjacent to the north eastern shore of Long Pond. Nitrogen loads from the landfill are currently being reduced by a 5 year program to mine the accumulated deposits and line and cap remaining materials. Nitrogen loads from the landfill site will be reduced by activities completed during the present 5 year phase, and will likely be eliminated if the landfill is capped in the future. Cost/benefit analyses will have to be conducted on all possible N loading reduction methodologies in order to select the optimal control strategies, priorities and schedules. 16 Figure 4a: Percent Contribution of Nitrogen Sources to the Madaket Harbor and Long Pond Estuarine System Figure 4b: Percent Contributions of Controllable Nitrogen Sources to the Madaket Harbor and Long Pond Estuarine System 17 Description of the Applicable Water Quality Standards The water qualityclassifications of the saltwater portions of Madaket Harbor and Long Pond Estuarine System are SA (all surface waters subject to the rise and fall of the tide), and the freshwater portions of the system are classified as B. Water qualitystandards of particular interest to the issues of cultural eutrophication are dissolved oxygen, nutrients, aesthetics, and excess plant biomass and nuisance vegetation. The Massachusetts water quality standards (314 CMR 4.0) contain numeric criteria for dissolved oxygen but have only narrative standards that relate to the other variables, as described below: 314 CMR 4.05(5)(a) states “Aesthetics – All surface waters shall be free from pollutants in concentrations or combinations that settle to form objectionable deposits; float as debris, scum, or other matter to form nuisances; produce objectionable odor, color, taste, or turbidity; or produce undesirable or nuisance species of aquatic life.” 314 CMR 4.05(5)(c) states, “Nutrients - Unless naturally occurring, all surface waters shall be free from nutrients in concentrations that would cause or contribute to impairment of existing or designated uses and shall not exceed the site specific criteria developed in a TMDL or as otherwise established…” 314 CMR 4.05(b) 1: Class SA: Dissolved Oxygen - a. Shall not be less than 6.0 mg/L unless background conditions are lower; b. Natural seasonal and daily variations above this level shall be maintained. Class B: Dissolved Oxygen - a. Shall not be less than 6.0 mg/L in cold water fisheries and not less than 5.0 mg/L in warm water fisheries; b. Where natural background conditions are lower, DO shall not be less than natural background conditions. Natural seasonal and daily variations that are necessary to protect existing and designated uses shall be maintained. Thus, the assessment of eutrophication is based on site-specific information within a general framework that emphasizes impairment of uses and preservation of a balanced indigenous flora and fauna. This approach is recommended by the US Environmental Protection Agency in their draft Nutrient Criteria Technical Guidance Manual for Estuarine and Coastal Marine Waters (EPA-822-B-01-003, Oct 2001). The Guidance Manual notes that lakes, reservoirs, streams and rivers may be subdivided by classes, allowing reference conditions for each class and facilitating cost-effective criteria development for nutrient management. However, individual estuarine and coastal marine waters tend to have unique characteristics and development of individual water body criteria is typically required. Methodology - Linking Water Quality and Pollutant Sources Extensive data collection and analyses have been described in detail in the MEP Technical Report. Those data were used by SMAST to assess the loading capacity of each embayment. Physical (Chapter V), chemical and biological (Chapters IV, VII, and VIII) data were collected and evaluated. The primary water quality objective was represented by conditions that: 1) Restore the natural distribution of eelgrass because it provides valuable habitat for shellfish and finfish; 2) Prevent harmful or excessive algal blooms; 18 3) Restore and preserve benthic communities; 4) Maintain dissolved oxygen concentrations that are protective of the estuarine communities. The details of the data collection, modeling and evaluation are presented and discussed in Chapters IV, V, VI, VII and VIII of the MEP Technical Report. The main aspects of the data evaluation and modeling approach are summarized below. The core of the Massachusetts Estuaries Project analytical method is the Linked Watershed-Embayment Management Modeling Approach. It fully links watershed inputs with embayment circulation and N characteristics, and is characterized as follows: •Requires site specific measurements within the watershed and each sub-embayment; •Uses realistic “best-estimates” of N loads from each land-use (as opposed to loads with built-in “safety factors” like Title 5 design loads); •Spatially distributes the watershed N loading to the embayment; •Accounts for N attenuation during transport to the embayment; •Includes a 2D or 3D embayment circulation model depending on embayment structure; •Accounts for basin structure, tidal variations, and dispersion within the embayment; •Includes N regenerated within the embayment; •Is validated by both independent hydrodynamic, N concentration, and ecological data; •Is calibrated and validated with field data prior to generation of “what if” scenarios. The Linked Model has been applied previously to watershed N management in over 30 embayments thus far throughout Southeastern Massachusetts. In these applications it became clear that the model can be calibrated and validated and has use as a management tool for evaluating watershed N management options. The Linked Model, when properly calibrated and validated for a given embayment becomes a N management- planning tool as described in the model overview below. The model can assess solutions for the protection or restoration of nutrient-related water quality and allows testing of management scenarios to support cost/benefit evaluations. In addition, once a model is fully functional it can be refined for changes in land-use or embayment characteristics at minimal cost. Also, since the Linked Model uses a holistic approach that incorporates the entire watershed, embayment and tidal source waters, it can be used to evaluate all projects as they relate directly or indirectly to water quality conditions within its geographic boundaries. The Linked Model provides a quantitative approach for determining an embayment's (1) N sensitivity, (2) N threshold loading levels (TMDL) and (3) response to changes in loading rate. The approach is fully field validated and unlike many approaches, accounts for nutrient sources, attenuation and recycling and variations in tidal hydrodynamics. This methodology integrates a variety of field data and models, specifically: • Monitoring - multi-year embayment nutrient sampling • Hydrodynamics - Embayment bathymetry (depth contours throughout the embayment) - Site-specific tidal record (timing and height of tides) - Water velocity records (in complex systems only) - Hydrodynamic model • Watershed Nitrogen Loading - Watershed delineation - Stream flow (Q) and N load - Land-use analysis (GIS) 19 - Watershed N model • Embayment TMDL - Synthesis - Linked Watershed-Embayment Nitrogen Model - Salinity surveys (for linked model validation) - Rate of N recycling within embayment - Dissolved oxygen record - Macrophyte survey - Infaunal survey (in complex systems) Application of the Linked Watershed-Embayment Model The approach developed by the MEP for applying the linked model to specific embayments for the purpose of developing target N loading rates includes: 1) Selecting one or two stations within the embayment system located close to the inland-most reach or reaches which typically have the poorest water quality within the system. These are called “sentinel” stations; 2) Using site-specific information and a minimum of three years of sub-embayment-specific data to select target threshold N concentrations for each sub-embayment. This is done by refining the draft target threshold N concentrations that were developed as the initial step of the MEP process. The target threshold N concentrations that were selected generally occur in higher quality waters near the mouth of the embayment system; 3) Running the calibrated water quality model using different watershed N loading rates to determine the loading rate that will achieve the target threshold N concentration at the sentinel station. Differences between the modeled N load required to achieve the target threshold N concentration and the present watershed N load represent N management goals for restoration and protection of the embayment system as a whole. Previous sampling and data analyses and the modeling activities described above resulted in four major outputs that were critical to the development of the TMDL. Two outputs are related to N concentration: a) The present N concentrations in the sub-embayments b) Site-specific target threshold N concentrations And, two outputs are related to N loadings: a) The present N loads to the sub-embayments b) Load reductions necessary to meet the site specific target N concentrations In summary: if the water quality standards are met by reducing the N concentration (and thus the N load) at the sentinel station(s), then the water quality goals will be met throughout the entire system. A brief overview of each of the outputs follows: Nitrogen concentrations in the embayment a) Observed “present” conditions: 20 Table 4 presents the average concentrations of N measured in this estuarine system from three years of data collection by the Nantucket Marine Department and SMAST (2002, 2003 and 2004). The overall means and standard deviations of the averages are presented in Appendix A (taken from Table VI-1 of the MEP Technical Report). Water quality sampling stations are shown in Figure 5. The sentinel station, M11 is labeled in bold italics. Table 4: Present Nitrogen Concentrations and Sentinel Station Target Threshold Nitrogen Concentrations for the Madaket Harbor and Long Pond Estuarine System 1 Average total N concentrations from present loading based on an average of the annual N means from 2002 - 2004.2 Target threshold N concentration at Hither Creek sentinel station M113Secondary target threshold N concentration for Long Pond (pond average of stations LOP01, LOP02, LOP03, LOP04) Figure 5: Water Quality Sampling Stations in the Madaket Harbor and Long Pond Estuarine System b) Modeled site-specific target threshold N concentrations: Sub-embayment Range of Observed Nitrogen Concentration 1 (mg/L) Target Threshold Nitrogen Concentration (mg/L) Madaket Harbor 0.336-0.422 Hither Creek 0.581-0.780 0.452 Long Pond 0.894-1.058 0.803 M1 M2 M6 M3 M10 0 M4 M11 M5 LOP01 LOP02 LOP03 LOP04 LOP05 21 A major component of TMDL development is the determination of the maximum concentrations of N (based on field data) that can occur without causing unacceptable impacts to the aquatic environment. Prior to conducting the analytical and modeling activities described above, SMAST selected appropriate nutrient-related environmental indicators and tested the qualitative and quantitative relationship between those indicators and N concentrations. The Linked Model was then used to determine site-specific target threshold N concentrations by using the specific physical, chemical and biological characteristics of each harbor embayment system. The target threshold N concentration for an embayment represents the average water column concentration of N that will support the habitat quality and dissolved oxygen concentrations being sought. The water column N level is ultimately controlled by the integration of the watershed N load, the N concentration in the inflowing tidal waters (boundary condition), dilution and flushing via tidal flows. The water column N concentration is modified by the extent of sediment uptake and/or regeneration and by direct atmospheric deposition. Target threshold N concentrations in this study were developed to restore or maintain SA waters or high habitat quality. In this system, high habitat quality was defined as stable fringing eelgrass beds in Hither Creek and overall diverse benthic animal communities and dissolved oxygen levels that would support Class SA waters. The target threshold nitrogen concentrations for the sub-embayments listed in Table 4 were determined as follows: The approach for determining nitrogen loading rates, which will maintain acceptable habitat quality throughout an embayment system, is to first identify a sentinel location within the embayment and second to determine the nitrogen concentration within the water column which will restore that location to the desired habitat quality. The sentinel location is selected such that the restoration of that one site will necessarily bring the other regions of the system to acceptable habitat quality levels. Once the sentinel site and its target threshold nitrogen concentration are determined, the MEP study modeled nitrogen loads until the targeted nitrogen concentration was achieved. The determination of the critical nitrogen threshold for maintaining high habitat with the Madaket Harbor and Long Pong Estuarine System is based on the nutrient and oxygen levels, temporal trends in eelgrass distribution and benthic community indicators. Overall the main, open water basin of Madaket Harbor is supporting high quality eelgrass habitat and productive benthic animal communities. However, the enclosed basin of Hither Creek is nitrogen enriched, demonstrated by high chlorophyll, periodic episodes of low oxygen, complete loss of eelgrass habitat, areas of dense drift algae and impaired benthic animal habitat. Long Pond is also nitrogen enriched beyond its assimilative capacity, but given the natural and organic matter enrichment of wetland influenced tidal basins such as brackish Long Pond the level of impairment is only moderate, demonstrated by high chlorophyll levels and a somewhat impaired benthic community. There is no evidence that eelgrass habitat ever existed previously in Long Pond, so this absence does not indicate impairment. Therefore, the threshold analysis focused on the goal of restoring eelgrass habitat for Hither Creek. Restoration of eelgrass to pre- 1951 coverage is now unlikely due to the enhanced depth of this sub-basin therefore restoration of the fringing eelgrass beds that existed in 1951 and 1995 is the management target. Nitrogen management to restore eelgrass habitat within Hither Creek will also result in restoration of the impaired benthic habitat, as nitrogen enrichment will be significantly reduced to the overall estuary. The most appropriate sentinel station for this system was determined to be located at the northern-most extent of the 1951 eelgrass coverage in Hither Creek which coincides with the baseline Nantucket water quality monitoring station M11. To achieve the restoration target of restoring the fringing eelgrass bends in Hither Creek requires lowering the level of nitrogen enrichment. In shallow systems like Hither Creek, eelgrass beds are sustainable at higher TN levels than in deeper waters. For example, the observed loss of eelgrass in Hither Creek is similar to that in shallow Farm Pond on Martha’s Vineyard where declining eelgrass was observed at a tidally averaged TN of 0.51 mg/L. Other similar examples include Bournes Pond where eelgrass can still be found (although stressed) 22 at the mouth of a tributary at a tidally averaged TN concentration of 0.481 mg/L, while the more stable beds in Israel’s Cove had a tidally average TN of 0.429 mg/L. Therefore to restore eelgrass habitat in Hither Creek the nitrogen concentration at the sentinel location needs to be between 0.48 and 0.43 mg/L TN. A threshold concentration of 0.45 mg/l TN was determined to be appropriate for the Hither Creek sentinel station to restore eelgrass and infaunal habitat with this basin. This target threshold concentration is consistent with high quality shallow water habitat in Bournes Pond and is similar to eelgrass observed within the Parker’s River at a tidally averaged TN level of 0.45 mg/L TN. This represents a relatively high target threshold nitrogen concentration as a result of the shallow depth of the area of potential eelgrass habitat. The benthic habitats in the brackish Long Pond system are naturally nitrogen enriched so a moderate reduction in nitrogen levels was determined to be sufficient to restore benthic habitat here. In tidal wetlands nitrogen levels between 1 and 2 mg/L TN are associated with unimpaired habitat. This is consistent with the only slight impairment of the North Head of Long Pond at TN levels of 0.894 mg/L and the moderately impaired benthic habitat in Long Pond at a basin averaged TN of 0.939 mg/L. Therefore, a secondary target nitrogen threshold concentration of 0.8 mg/L TN (pond-wide average) was determined to be supportive of benthic animal habitat in this system. Watershed nitrogen management to achieve this “check” nitrogen level will ensure restoration of infaunal habitats within the down-gradient reach as well. The secondary criteria should be met when the target threshold is met at the sentinel station. Based on this, eelgrass is the primary nitrogen management goal for Hither Creek and improved infaunal habitat quality the management target for Long Pond. The findings of the analytical and modeling investigations for theses embayment systems are discussed and explained below. Nitrogen loadings to the embayment a) Present Loading rates: In the Madaket Harbor and Long Pond Estuarine System overall, the highest N loading from controllable sources is from on-site wastewater treatment systems. The MEP Technical Report calculates that septic systems account for 58% of the controllable N load to Madaket Harbor and Long Pond. Other sources include the landfill (24%), fertilizers (8%), and runoff from impervious surfaces (10%). The MEP study determined that sediments did not contribute nitrogen to this system. Atmospheric nitrogen deposition to the estuary and watershed surface area was found to be significant (58% of the total load) however this source is considered uncontrollable. (See Figures 4a and 4b.) A subwatershed breakdown of N loading, by source, is presented in Table 5. The data on which Table 5 is based can be found in Table ES-1 and Table IV-2 of the MEP Technical Report. As previously indicated, the present N loadings to these embayment systems must be reduced in order to restore the impaired conditions and to avoid further nutrient-related adverse environmental impacts. The critical final step in the development of the TMDL is modeling and analysis to determine the loadings required that will achieve the target threshold N concentrations. 23 Table 5: Present Nitrogen Loadings to the Madaket Harbor and Long Pond Estuarine System Sub-embayment Present Land Use Load1 (kg N/day) Present Septic System Load (kg N/day) Present Watershed Load2 (kg N/day) Present Atmospheric Deposition3 (kg N/day) Present Benthic Flux4 (kg N/day) Total Nitrogen Load from All Sources5 (kg N/day) Madaket Harbor 0.279 0.384 0.663 8.603 17.952 27.218 Hither Creek 1.134 2.907 4.041 0.534 0 4.575 Madaket Ditch 0.923 1.510 2.433 --0.061 2.494 Long Pond 2.888 0.342 3.230 0.975 3.283 7.488 North Head Long Pond 0.167 0.071 0.238 0.693 0.995 1.926 System Total 5.392 5.214 10.605 10.805 22.291 43.701 1 Includes fertilizers, runoff, landfill and atmospheric deposition to lakes and natural surfaces2Includes fertilizer, runoff, landfill, atmospheric deposition to lakes and natural surfaces and wastewater inputs3Atmospheric deposition to the estuarine surface only4Nitrogen loading from sediments, negative fluxes have been set to zero5Composed of fertilizer, runoff, landfill, wastewater, atmospheric deposition and benthic nitrogen input b) Nitrogen loads necessary for meeting the site-specific target threshold N concentrations: Table 6 lists the present watershed N loadings from the Madaket Harbor and Long Pond Estuarine System and the percent watershed load reductions necessary to achieve the target threshold N concentration at the sentinel stations. It is very important to note that load reductions can be produced through a variety of strategies: reduction of any or all sources of N; increasing the natural attenuation of N within the freshwater systems; and/or modifying the tidal flushing through inlet reconfiguration (where appropriate). This scenario establishes the general degree and spatial pattern of reduction that will be required for restoration of the N impaired portions of this system. The Town of Nantucket should take any reasonable actions to reduce the controllable N sources. 24 Table 6: Present Watershed Nitrogen Loading Rates, Calculated Loading Rates that are Necessary to Achieve Target Threshold Nitrogen Concentrations, and the Percent Reductions of the Existing Loads Necessary to Achieve the Target Threshold Loadings Sub-embayment System Present Total Watershed Load 1 (kg/day) Target Threshold Watershed Load2 (kg/day) Percent Watershed Load Reductions Needed to Achieve Target Madaket Harbor 0.663 0.663 0% Hither Creek 4.041 1.134 71.9% Madaket Ditch 2.433 2.433 0% North Head Long Pond 0.238 0.238 0% Long Pond 3.230 1.101 65.9% Total for Madaket Harbor/ Long Pond Estuarine System 10.605 5.570 47.5% 1 Composed of septic, fertilizer, landfill and runoff loadings.2 Target threshold watershed load is the N load from the watershed (including natural background) needed to meet the target threshold N concentrations identified in Table 4, above. Taken from Tables ES-2 and VIII-3 in the MEP Technical Report Total Maximum Daily Loads As described in EPA guidance, a total maximum daily load (TMDL) identifies the loading capacity of a water body for a particular pollutant. EPA regulations define loading capacity as the greatest amount of loading that a water body can receive without violating water quality standards. The TMDLs are established to protect and/or restore the estuarine ecosystem, including eelgrass, the leading indicator of ecological health, thus meeting water quality goals for aquatic life support. Because there are no “numerical” water quality standards for N, the TMDLs for the Madaket Harbor and Long Pond estuarine system are aimed at establishing the loads that would correspond to specific N concentrations determined to be protective of the water quality and ecosystems. The development of a TMDL requires detailed analyses and mathematical modeling of land use, nutrient loads, water quality indicators, and hydrodynamic variables (including residence time) for each waterbody system. The results of the mathematical model are correlated with estimates of impacts on water quality, including negative impacts on eelgrass (the primary indicator), as well as dissolved oxygen, chlorophyll a and benthic infauna. The TMDL can be defined by the equation: TMDL = BG + WLAs + LAs + MOS Where: TMDL = loading capacity of receiving water BG = natural background WLAs = portion allotted to point sources LAs = portion allotted to (cultural) non-point sources 25 MOS = margin of safety Background Loading Natural background N loading is included in the loading estimates, but is not quantified or presented separately. It is a component of the target watershed threshold. Waste Load Allocations Waste load allocations identify the portion of the loading capacity allocated to existing and future point sources of wastewater. In the Madaket Harbor and Long Pond estuary system there are no NPDES regulated point source discharges in the watershed. EPA interprets 40 CFR 130.2(h) to require that allocations for NPDES regulated discharges of storm water also be included in the waste load component of the TMDL. It should be noted that no part of the Town of Nantucket is designated as an urbanized area by EPA and thus is not required to obtain coverage under the NPDES Phase II General Permit for Storm-water Discharges from Small Municipal Separate Storm Sewer Systems (MS4s) in 2003. Subsequently, in the Madaket Harbor and Long Pond watershed there are no Phase II NPDES permitted stormwater discharges. However, there are a few storm water pipes that discharge directly to water bodies and MassDEP has determined that these must also be treated as part of a waste load allocation. In the Madaket/Long Pond watershed, as in much of Cape Cod and the Islands, the vast majority of storm-water percolates into the ground and aquifer and proceeds into the embayment systems through groundwater migration. The Linked Model accounts for storm-water and groundwater loadings in one aggregate allocation as a non-point source – combining the assessments of waste water and storm-water (including storm-water that infiltrates into the soil and direct discharge pipes into water bodies) for the purpose of developing control strategies. Based on land use, the Linked Model accounts for loading from storm-water, but does not differentiate storm-water into a load and waste load allocation. Since the majority of the nitrogen loading comes from septic systems, and to a lesser extent fertilizer, the landfill and storm-water runoff that infiltrates into the groundwater, the allocation of nitrogen for any storm- water pipes that discharge directly to any of the embayments is expected to be insignificant as compared to the overall groundwater load. This is based on determining the percent of impervious surface within 200 feet of the waterbody and calculating the potential relative load from this area via storm drains compared to the overall load. (For the purposes of waste load allocation it was assumed that all impervious surfaces within 200ft of the shoreline discharge directly to the waterbody.) MassDEP has calculated the potential waste load allocation for this 200 foot buffer zone previously in nitrogen TMDLs for eleven embayments on Cape Cod. Percent contribution of N into these waterbodies when all impervious surface within 200 feet of the shoreline is considered ranged from 0.2% - 1.1% (mean = 0.53%). Without exception, this calculated load was negligible when compared to other sources. Because the land use and soils in Nantucket surrounding Madaket Harbor and Long Pond is typical of Cape Cod and the Islands and similar to other embayments where this calculation was performed it is assumed that the load from stormwater runoff from impervious surfaces within 200 feet of the Madaket Harbor and Long Pond system is also negligible. Load Allocations Load allocations identify the portion of loading capacity allocated to existing and future nonpoint sources. In the case of the Madaket Harbor and Long Pond estuary system the locally controllable nonpoint source loadings are from on-site subsurface wastewater disposal systems (septic systems) and other land uses (which include storm-water runoff, except from impervious cover within 200 feet of the waterbody which is defined above as part of the waste load, the landfill and fertilizers). Figure 4b (above) and Figure 6 (below) illustrate that septic systems are the most significant portion of the controllable N load (5.2 kg N/day), with landfill contribution a distant second (2.1 kg N/day). Fertilizers and runoff combined contribute 1.7 kg N/day (from 26 Table IV-2 in the MEP Technical Report). In addition, there are nonpoint sources of N from sediments, natural background and atmospheric deposition that are not feasibly controllable. Figure 6: Madaket Harbor and Long Pond Estuarine System Locally Controllable N Sources Generally, storm-water that is subject to the EPA Phase II Program is considered a part of the waste load allocation, rather than the load allocation (see waste load allocation discussion). As discussed above and presented in Chapter IV, V, and VI, of the MEP Technical Report, on Cape Cod and the Islands the vast majority of storm-water percolates into the aquifer and enters the embayment system through groundwater, thus defining the stormwater in pervious areas to be a component of the nonpoint source load allocation. Therefore, the TMDL accounts for storm-water and groundwater loadings in one aggregate allocation as a non-point source, thus combining the assessments of wastewater and storm-water for the purpose of developing control strategies. As the Phase II Program is implemented in Nantucket, new studies, and possibly further modeling, will identify what portion of the storm-water load may be controllable through implementation of Best Management Practices (BMPs). The sediment loading rates incorporated into the TMDL are lower than the existing benthic input listed in Table 5 above because projected reductions of N loadings from the watershed will result in reductions of nutrient concentrations in the sediments and therefore, over time, reductions in loadings from the sediments will occur. Benthic N flux is a function of N loading and particulate organic N (PON). Projected benthic fluxes are based upon projected PON concentrations and watershed N loads and are calculated by multiplying the present N flux by the ratio of projected PON to present PON using the following formulae: Projected N flux = (present N flux) (PON projected / PON present) When:PON projected = (Rload ) (DPON) + PON present offshore When:Rload = (projected N load) / (Present N load) And:D PON is the PON concentration above background determined by: D PON = (PON present embayment – PON present offshore) 27 The benthic flux modeled for the Madaket Harbor and Long Pond estuary system is reduced from existing conditions based on the load reduction and the observed PON concentrations within each sub-embayment relative to Nantucket Sound (boundary condition). The benthic flux input to each sub-embayment was reduced (toward zero) based on the reduction of N in the watershed load. The loadings from atmospheric sources incorporated into the TMDL however, are the same rates presently occurring because, as discussed above, local control of atmospheric loadings is not considered feasible. Margin of Safety Statutes and regulations require that a TMDL include a margin of safety (MOS) to account for any lack of knowledge concerning the relationship between load and wasteload allocations and water quality [CWA para 303 (d)(20©, 40C.G.R. para 130.7©(1)]. The EPA’s 1991 TMDL Guidance explains that the MOS may be implicit, i.e., incorporated into the TMDL through conservative assumptions in the analysis, or explicit, i.e., expressed in the TMDL as loadings set aside for the MOS. The MOS for the Madaket Harbor and Long Pond TMDLs are implicit and the conservative assumptions in the analyses that account for the MOS are described below. 1. Use of conservative data in the linked model: The watershed N model provides conservative estimates of N loads to the embayment. Nitrogen transfer through direct groundwater discharge to estuarine waters is based upon studies indicating negligible aquifer attenuation and dilution, i.e. 100% of load enters embayment. This is a conservative estimate of loading because studies have also shown that in some areas less than 100% of the load enters the estuary. Nitrogen from the upper watershed regions, which travels through ponds or wetlands, almost always enters the embayment via stream flow, and is directly measured (over 12-16 months) to determine attenuation. In these cases the land-use model has shown a slightly higher predicted N load than the measured discharges in the streams/rivers that have been assessed to date. Therefore, the watershed model as applied to the surface water watershed areas again presents a conservative estimate of N loads because the actual measured N in streams was lower than the modeled concentrations. The hydrodynamic and water quality models have been assessed directly. In the many instances where the hydrodynamic model predictions of volumetric exchange (flushing) have also been directly measured by field measurements of instantaneous discharge, the agreement between modeled and observed values has been >95%. Field measurement of instantaneous discharge was performed using acoustic doppler current profilers (ADCP) at key locations within the embayment (with regards to the water quality model, it was possible to conduct a quantitative assessment of the model results as fitted to a baseline dataset - a least squares fit of the modeled versus observed data showed an R2>0.95, indicating that the model accounted for 95% of the variation in the field data). Since the water quality model incorporates all of the outputs from the other models, this excellent fit indicates a high degree of certainty in the final result. The high level of accuracy of the model provides a high degree of confidence in the output; therefore, less of a margin of safety is required. Similarly, the water column N validation dataset was also conservative. The model is validated to measured water column N. However, the model predicts average summer N concentrations. The very high or low measurements are marked as outliers. The effect is to make the N threshold more accurate and scientifically defensible. If a single measurement two times higher than the next highest data point in the series raises the average 0.05 mg N/L, this would allow for a higher “acceptable” load to the embayment. Marking the very high outlier is a way of preventing a single and rare bloom event from changing the N threshold for a system. This effectively strengthens the data set so that a higher margin of safety is not required. 28 Finally, the predicted reductions in benthic regeneration of N are most likely underestimates, i.e. conservative. The reduction is based solely on a reduced deposition of PON, due to lower primary production rates under the reduced N loading in these systems. As the N loading decreases and organic inputs are reduced, it is likely that rates of coupled remineralization-nitrification, denitrification and sediment oxidation will increase. Benthic regeneration of N is dependent upon the amount of PON deposited to the sediments and the percentage that is regenerated to the water column versus being denitrified or buried. The regeneration rate projected under reduced N loading conditions was based upon two assumptions (1) PON in the embayment in excess of that of inflowing tidal water (boundary condition) results from production supported by watershed N inputs and (2) Presently enhanced production will decrease in proportion to the reduction in the sum of watershed N inputs and direct atmospheric N input. The latter condition would result in equal embayment versus boundary condition production and PON levels if watershed N loading and direct atmospheric deposition could be reduced to zero (an impossibility of course). This proportional reduction assumes that the proportion of remineralized N will be the same as under present conditions, which is almost certainly an underestimate. As a result, future N regeneration rates are overestimated which adds to the margin of safety. 2. Conservative sentinel station/target threshold nitrogen concentration: Conservatism was used in the selection of the sentinel stations and target threshold N concentrations. The sites were chosen that had stable eelgrass or benthic animal (infaunal) communities, and not those just starting to show impairment, which would have slightly higher N concentration. Meeting the target threshold N concentrations at the sentinel stations will result in reductions of N concentrations in the rest of the system. 3. Conservative approach: The target loads were based on tidally averaged N concentrations on the outgoing tide, which is the worst case condition because that is when the N concentrations are the highest. The N concentrations will be lower on the flood tides and therefore this approach is conservative. In addition to the margin of safety within the context of setting the N threshold levels as described above, a programmatic margin of safety also derives from continued monitoring of these embayments to support adaptive management. This continuous monitoring effort provides the ongoing data to evaluate the improvements that occur over the multi-year implementation of the N management plan. This will allow refinements to the plan to ensure that the desired level of restoration is achieved. Seasonal Variation Since the TMDLs for the waterbody segments are based on the most critical time period, i.e. the summer growing season, the TMDLs are protective for all seasons. The daily loads can be converted to annual loads by multiplying by 365 (the number of days in a year). Nutrient loads to the embayment are based on annual loads for two reasons. The first is that primary production in coastal waters can peak in both the late winter-early spring and in the late summer-early fall periods. Second, as a practical matter, the types of controls necessary to control the N load, the nutrient of primary concern, by their very nature do not lend themselves to intra-annual manipulation since the majority of the N is from non-point sources. Thus, the annual loads make sense since it is difficult to control non-point sources of N on a seasonal basis and N sources can take considerable time to migrate to impacted waters. 29 TMDL Values for the Madaket Harbor and Long Pond Estuarine System As outlined above, the total maximum daily loadings of N that would provide for the restoration and protection of the embayment were calculated by considering all sources of N grouped by natural background, point sources and non-point sources. A more meaningful way of presenting the loadings data from an implementation perspective is presented in Table 7. In this table the N loadings from the atmosphere are listed separately from the target watershed threshold loads which are composed of natural background N along with locally controllable N from the on-site subsurface wastewater disposal systems, the landfill, storm-water runoff and fertilizer sources. In the case of the Madaket Harbor and Long Pond system the TMDLs were calculated by projecting reductions in locally controllable septic systems in the Hither Creek subwatershed as well as removing the landfill load from the Long Pond subwatershed. Once again the goals of these TMDLs are to achieve the identified target threshold N concentration at the identified sentinel stations. The target loads identified in this table represents one alternative-loading scenario to achieve that goal but other scenarios may be possible and approvable as well. Table 7: The Total Maximum Daily Loads (TMDL) for the Madaket Harbor and Long Pond Estuarine System, Represented as the Sum of the Calculated Target Threshold Loads, Atmospheric Deposition and Sediment Load Sub-embayment System Target Threshold Watershed Load1 (kg N/day) Atmospheric Deposition (kg N/day) Nitrogen Load from Sediments2 (kg N/day) TMDL3 (kg N/day) Madaket Harbor 0.663 8.603 17.952 27.218 Hither Creek 1.134 0.534 0 1.668 Madaket Ditch 2.433 -0.061 2.494 North Head Long Pond 0.238 0.693 0.995 1.926 Long Pond 1.101 0.975 2.273 4.349 Total for Systems 5.570 10.805 21.281 37.656 1Target threshold watershed load (including natural background) is the load from the watershed needed to meet the embayment target threshold nitrogen concentration identified in Table 4.2 Projected sediment N loadings obtained by reducing the present benthic flux loading rates (Table 5) proportional to proposed watershed load reductionsand factoring in the existing and projected future concentrations of PON. (Negative fluxes set to zero.)3Sum of target threshold watershed load, sediment load and atmospheric deposition load. Implementation Plans The critical element of this TMDL process is achieving the sentinel station specific target threshold N concentrations presented in Table 4 above that are necessary for the restoration and protection of water quality and eelgrass habitat within the Madaket Harbor and Long Pond estuarine system. In order to achieve these target threshold N concentrations, N loading rates must be reduced throughout the harbor embayment system. 30 It should be noted that the Town of Nantucket is currently involved in a five year implementation process to reduce the landfill contribution to the nitrogen load of Long Pond by mining and removing some material and lining/capping the remaining material. It is expected that the landfill nitrogen loads will likely be eliminated after completion of this project. Based on a modeled future scenario of removing the landfill N load from the system, the MEP study predicts that removal of the landfill load will result in a 20% reduction in total watershed N load. This reduction is not sufficient to reach the target threshold nitrogen concentration of 0.45 mg/l at the sentinel station. Additional load reductions are required to meet the 0.45 mg/l target threshold nitrogen concentration. However, as previously noted, there is a variety of loading reduction scenarios that could achieve the target threshold N concentrations. Local officials can explore other loading reduction scenarios through additional modeling as part of their Comprehensive Wastewater Management Plan (CWMP). It must be demonstrated however, that any alternative implementation strategies will be protective of the entire embayment system. To this end, additional linked model runs can be performed by the MEP at a nominal cost to assist the planning efforts of the town in achieving target N loads that will result in the desired target threshold N concentration. The CWMP should include a schedule of the selected strategies and estimated timelines for achieving those targets. However, the MassDEP realizes that an adaptive management approach may be used to observe implementation results over time and allow for adjustments based on those results. Because the vast majority of controllable N load is from septic systems for private residences the CWMP should assess the most cost-effective options for achieving the target N watershed loads, including but not limited to, sewering and treatment for N control of sewage and septage at either centralized or de-centralized locations and denitrifying systems for all private residences. Nantucket is urged to meet the target threshold N concentrations by reducing N loadings from any and all sources, through whatever means are available and practical, including reductions in storm-water runoff and/or fertilizer use within the watershed through the establishment of local by-laws and/or the implementation of storm-water BMPs in addition to reductions in on-site subsurface wastewater disposal system loadings. Based on land-use and the fact that the watersheds of these systems are located completely within the Town of Nantucket it follows that nitrogen management necessary for the restoration of the Madaket Harbor and Long Pond Estuarine System may be formulated and implemented entirely through the Town of Nantucket’s actions. MassDEP’s MEP Implementation Guidance report: http://www.mass.gov/dep/water/resources/coastalr.htm#guidance provides N loading reduction strategies that are available to Nantucket and could be incorporated into the implementation plans. The following topics related to N reduction are discussed in the Guidance: Wastewater Treatment On-Site Treatment and Disposal Systems Cluster Systems with Enhanced Treatment Community Treatment Plants Municipal Treatment Plants and Sewers Tidal Flushing Channel Dredging Inlet Alteration Culvert Design and Improvements Storm-water Control and Treatment * Source Control and Pollution Prevention Storm-water Treatment Attenuation via Wetlands and Ponds 31 Water Conservation and Water Reuse Management Districts Land Use Planning and Controls Smart Growth Open Space Acquisition Zoning and Related Tools Nutrient Trading *Nantucket is not one of the 237 communities in Massachusetts covered by the Phase II storm-water program requirements. Monitoring Plan MassDEP is of the opinion that there are two forms of monitoring that are useful to determine progress towards achieving compliance with the TMDL. MassDEP’s position is that implementation will be conducted through an iterative process where adjustments maybe needed in the future. The two forms of monitoring include 1) tracking implementation progress as approved in the Nantucket CWMP plan and 2) monitoring water quality and habitat conditions in the estuaries, including but not limited to, the sentinel stations identified in the MEP Technical Report. The CWMP will evaluate various options to achieve the goals set out in the TMDL report and the MEP Technical Report. It will also make a final recommendation based on existing or additional modeling runs, set out required activities, and identify a schedule to achieve the most cost effective solution that will result in compliance with the TMDL. Once approved by the Department, tracking progress on the agreed upon plan will, in effect, also be tracking progress towards water quality improvements in conformance with the TMDL. Relative to water quality MassDEP believes that an ambient monitoring program much reduced from the data collection activities needed to properly assess conditions and to populate the model, will be important to determine actual compliance with water quality standards. Although the TMDL values are not fixed, the target threshold N concentrations at the sentinel stations are fixed. Through discussions amongst the MEP it is generally agreed that existing monitoring programs which were designed to thoroughly assess conditions and populate water quality models can be substantially reduced for compliance monitoring purposes. Although more specific details need to be developed on a case-by-case basis MassDEP believes that about half the current effort (using the same data collection procedures) would be sufficient to monitor compliance over time and to observe trends in water quality changes. In addition, the benthic habitat and communities would require periodic monitoring on a frequency of about every 3-5 years. Finally, in addition to the above, existing monitoring conducted by MassDEP for eelgrass should continue into the future to observe any changes that may occur to eelgrass populations as a result of restoration efforts. The MEP will continue working with the watershed communities to develop and refine monitoring plans that remain consistent with the goals of the TMDL. It must be recognized however that development and implementation of a monitoring plan will take some time, but it is more important at this point to focus efforts on reducing existing watershed loads to achieve water quality goals. Reasonable Assurances MassDEP possesses the statutory and regulatory authority, under the water quality standards and/or the State Clean Water Act (CWA), to implement and enforce the provisions of the TMDL through its many permitting programs including requirements for N loading reductions from on-site subsurface wastewater disposal systems. However, because most non-point source controls are voluntary, reasonable assurance is based on the 32 commitment of the locality involved. Nantucket has demonstrated this commitment through the comprehensive wastewater planning that they initiated well before the generation of the TMDL. The town expects to use the information in this TMDL to generate support from their citizens to take the necessary steps to remedy existing problems related to N loading from on-site subsurface wastewater disposal systems, storm-water, and runoff (including fertilizers), and to prevent any future degradation of these valuable resources. Moreover, reasonable assurances that the TMDL will be implemented include enforcement of regulations, availability of financial incentives and local, state and federal programs for pollution control. Storm-water NPDES permit coverage will address discharges from municipally owned storm-water drainage systems. Enforcement of regulations controlling non-point discharges include local implementation of the Commonwealth’s Wetlands Protection Act and Rivers Protection Act, Title 5 regulations for on-site subsurface wastewater disposal systems and other local regulations (such as the Town of Rehoboth’s stable regulations). Financial incentives include federal funds available under Sections 319, 604 and 104(b) programs of the CWA, which are provided as part of the Performance Partnership Agreement between MassDEP and EPA. Other potential funds and assistance are available through the Massachusetts Department of Agriculture’s Enhancement Program and the United States Department of Agriculture’s Natural Resources Conservation Services. Additional financial incentives include income tax credits for Title 5 upgrades and low interest loans for Title 5 on-site subsurface wastewater disposal system upgrades available through municipalities participating in this portion of the state revolving fund program. As the town implements these TMDLs the loading values (kg/day of N) will be used by MassDEP for guidance for permitting activities and should be used by the community as a management tool. 33 Appendix A: Summary of the Nitrogen Concentrations for Madaket Harbor/Long Pond Estuarine System. (From the MEP Technical Report, Linked Watershed-embayment Model to Determine Critical Nitrogen Loading Threshold for the Madaket Harbor and Long Pond Estuarine System, Town of Nantucket, MA, March, 2011) 34 Appendix B: Madaket Harbor/ Long Pond Estuarine System Five Total Nitrogen TMDLs Sub-embayment Segment ID Description TMDL (kg N/day) Madaket Harbor MA97-27_2008 Waters encompassed within imaginary lines from Eel Point to the northern tip of Esther Island, from the southern tip of Esther Island southeasterly to the opposite shore and from Jackson Point easterly to Little Neck, Nantucket. Listed on the 2008 CWA §303(d) list for pathogens. 27.22 Hither Creek MA97-28_2008 From the outlet of Madaket Ditch to Madaket Harbor at an imaginary line drawn easterly from Jackson Point to Little Neck, Nantucket. Listed on the 2008 CWA §303(d) list for nutrients, organic enrichment/low DO. 1.67 Madaket Ditch --Determined to be impaired for nutrients during the development of this TMDL.2.49 North Head Long Pond --Determined to be impaired for nutrients during the development of this TMDL.1.93 Long Pond MA97-29_2008 South of Madaket Road, including White Goose Cove, Nantucket. Listed on the 2008 CWA §303(d) list for nutrients, organic enrichment/low DO, pathogens, turbidity. 4.35 Total for System 37.66 MASSACHUSETTS ESTUARIES PROJECT 85 that the system should be capable of supporting healthy infaunal communities should the organic matter loadings be reduced. The infaunal community based classification (Table VIII-1) throughout Sesachacha Pond is fully supported by the lack of eelgrass habitat and the water quality data discussed in the text above. VIII.2 THRESHOLD NITROGEN CONCENTRATIONS The approach for determining nitrogen loading rates, which will maintain acceptable habitat quality throughout and embayment system, is to first identify a sentinel location within the embayment and second to determine the nitrogen concentration within the water column which will restore that location to the desired habitat quality. The sentinel location is selected such that the restoration of that one site will necessarily bring the other regions of the system to acceptable habitat quality levels. Once the sentinel site and its target nitrogen level are determined, the Linked Watershed-Embayment Model is used to sequentially adjust nitrogen loads until the targeted nitrogen concentration is achieved. Table VIII-1. Summary of Nutrient Related Habitat Health within the Sesachacha Pond Estuary on the eastern coast of Nantucket Island within the Town of Nantucket, MA, based upon assessment data presented in Chapter VII. The system is presently structured as a great salt pond consisting of a single basin formed from seawater entry to a coastal kettle pond. Sesachacha Pond System Health Indicator Main Basin Dissolved Oxygen SI1 Chlorophyll SD2 Macroalgae --3 Eelgrass --4 Infaunal Animals SI5/SD 6 Overall: SD 1 – oxygen depletions frequent to 4 mg/L., and periodically to <2 mg/L. 2 – chlorophyll levels generally >20 ug/L, reaching 60 ug/l and >100 ug/L in bloom periods. 3 -- macroalgae was difficult to assess due to poor light penetration, however, large accumulations of drift algae have not been reported for this system 4 – no evidence this basin is supportive of eelgrass. 5 – main basin low numbers of species (generally <6) moderate numbers of individuals, but dominated by opportunistic species (primarily Streblospio). 6 – western basin (Transect B, figure VII-9) infaunal community severely depleted, low numbers of individuals (<72) & species (<4). H = healthy habitat conditions; MI = Moderate Impairment; SI = Significant Impairment; SD = Severe Degradation; -- = not applicable to this estuarine reach MASSACHUSETTS ESTUARIES PROJECT 86 Within the Sesachacha Pond System the most appropriate sentinel station location is generally in the center of the basin, but given the horizontally well mixed nature of this great salt pond, Station 1 in Figure II-1 was selected as the sentinel station for threshold development. This location was selected because it is relatively deep and has prior data collection from which to assess long-term trends. As noted in previous sections, concentrations at the sentinel station approximate concentrations throughout the pond waters (i.e. it is representative of other pond locations). Following the MEP protocol, since eelgrass has not been documented in Sesachacha Pond, restoration of infaunal habitat is the restoration goal for this aquatic system. Infaunal animal habitat is a critical resource to the Sesachacha Pond System and estuaries in general. Since the infaunal community at all sites within the Pond are either dominated by organic matter enrichment species or are depleted, comparisons to the muddy basins of other estuarine systems in the MEP region were relied upon. This analysis would suggest that a healthy infaunal habitat would clearly be achieved at an average nitrogen level of TN <0.5 mg TN L-1. This level was found for Popponesset Bay where, based upon the infaunal analysis coupled with the nitrogen data (measured and modeled), nitrogen levels on the order of 0.4 to 0.5 mg TN L-1 were found supportive of high infaunal habitat quality. Similarly, in the deeper basins of Three Bays System, healthy infaunal areas are found at nitrogen levels of TN <0.42 mg TN L-1 (Cotuit Bay and West Bay), with moderate impairment in areas where nitrogen levels of TN >0.5 mg TN L-1. Sesachacha Pond currently has a low watershed nitrogen load, with external loading dominated by direct atmospheric input, and moderate summer input from its sediments and only periodic tidal exchange. The result is nitrogen levels reaching 1.5 mg TN L-1 and average TN levels of ~ 1 mg TN L-1. Therefore it is not clear if average summer TN levels can be reduced to <0.5 mg L-1 or if this level has been achieved at any time in past centuries. The Pond was always cited to be used for shellfish transplanting and therefore likely has been somewhat nitrogen enriched, supporting moderate phytoplankton levels. Therefore, the MEP Technical Team determined that a higher TN level <0.6 mg TN L-1 would likely support a moderately impaired infaunal community, yet conditions that should also support shellfish. The modeling simulations in Section VIII-3 targeted the 0.5 mg TN L-1 for healthy habitat and also assessed a higher level of 0.6 mg TN L-1 for a moderately impaired condition that may be more reflective of the natural condition of this system in its present configuration. It is important to note that the modeled maximum and average TN levels are likely conservative estimates as they do not include potential reductions in the rate of sediment nitrogen regeneration often associated with the lowering of nitrogen enrichment of embayment waters. VIII.3 DEVELOPMENT OF TARGET NITROGEN LOADS After developing the dispersion-mass balance model of Sesachacha Pond to simulate conditions that exist as a result of present management practices, the model was used to simulate a modified management approach that could be followed to improve water quality conditions in the pond year-round. The habitat quality in Sesachacha Pond has been historically moderate to poor, depending on the intensity of management, specifically the frequency and duration of openings to the ocean. Throughout the 1980’s, the pond was not actively managed (openings ceased), and salinities dropped as low as 2 ppt in 1989. It was in this year that the Town sought the proper environmental permits that would allow again the periodic breaching of an inlet to the Atlantic Ocean, in order to improve water quality conditions. Beginning in the early 1990’s, with MASSACHUSETTS ESTUARIES PROJECT 87 the permits in place, the latest era of active management of Sesachacha Pond began. Presently, Pond water quality is managed by bi-annual breachings of the barrier beach, once each in the spring and fall (Curley, 2004). Other breaches are cut as required in order to lower the water level of Pond when it threatens lower lying properties along its shore (Conant, 2006). Between 1967 and 2005, there have been only seven years where maximum recorded salinities have been equal to or greater than 25 ppt (see Chapter 6). Five of those years fall within the 10-year period from 1996 through 2005, which indicates that present management practices have been more effective in controlling conditions in the pond. With a goal of seeking further improvements in water quality conditions in the Pond, an alternate management scheme was modeled using the dispersion-mass balance model developed for Sesachacha Pond. One goal of this proposed management scenario is to prevent salinity in the pond from dropping below 22 ppt at any point of the year. Another goal is to reduce TN concentrations in the pond during the summer months, when benthic regeneration and algae production is greatest. Both of these goals are related, as better flushing management results in both higher salinities and lower nitrogen levels in pond waters. A simple way to achieve these goals is to add an additional mid-summer breach event each year. To model the effect of adding this mid-summer breach, first, the spring-to-fall 2003 time period was modeled. This period was selected because it offers a good approximation of typical conditions with regard to the duration of the spring-time opening (6 days), water quality data was available for this period, and the average net fresh water recharge rate (2.2 ft3/sec) could be determined by an analysis of the salinity data records from 1998, 2003, 2004 and 2005. Similar to the results of the modeled 2004 spring-to-fall season discussed in Chapter VI, Figures VIII-1 and VIII-2 show comparisons between measured data and concentrations predicted by the pond model. The resulting average modeled salinity over the whole modeled period is 24.7 ppt, and the average TN concentration is 0.87 mg/L. Figure VIII-1. Comparison of measured (black circles) and modeled (red triangles) salinities through the summer of 2003 (R2=0.74, RMS error=1.31 ppt). Present conditions with pond openings in Spring and Fall. MASSACHUSETTS ESTUARIES PROJECT 88 Figure VIII-2. Comparison of measured (black circles) and modeled (red triangles) TN concentrations through the summer of 2003 (R2=0.83, RMS error=0.13 mg/L). Present conditions with pond openings in Spring and Fall. After modeling the 2003 season, the alternative of including a mid-summer breach was modeled. For this scenario, the mid-summer breach was made 90 days after the closure of the first breach. This breach was modeled as if it were as successful as the spring 2003 breach, which lasted for six days. A comparison of modeled salinities, showing results for runs with the mid-summer breach and without (i.e., present management practice) is presented in Figure VIII-3. After the second breach, salinities rise above 30 ppt. At the end of the simulation period, the pond salinities with the mid-summer breach are approximately 5 ppt greater then the salinities under existing management conditions (i.e. spring and fall breaches only). Both model runs include a fall breach which only draws down the pond volume, but does not permit tidal exchange with the ocean. This is the typical effect of the fall breach. The average salinity for the mid-summer breach run is 26.0 ppt, which represents an improvement of 1.3 ppt over the entire modeled period. The attendant comparison of modeled TN is presented in Figure VIII-4. The mid-summer breach lowers TN levels by 0.50 mg/L to approximately 0.40 mg/L. At the end of the simulation period, TN concentrations are 0.4 mg/L lower after the mid-breach simulation compared to the concentrations for the simulations of existing conditions. The average TN level for the entire simulation period also drops to 0.68 mg/L, which is a substantial improvement of 0.09 mg/l over modeled 2003 average conditions. MASSACHUSETTS ESTUARIES PROJECT 89 Figure VIII-3. Comparison of modeled 2003 salinities for case where the pond is breached only in the spring (thick black dot-dashed line) and also when it is breached an additional time mid- summer. Model results for the following 2004 spring- to-fall season (thin red dash dot line) show how salinities change if the mid-summer breach is performed again. Figure VIII-4. Comparison of modeled 2003 TN for case where the pond is breached only in the spring (thick black line) and also when it is breached an additional time mid-summer (dot- dashed line). Model results for the following 2004 spring- to-fall season (thin red dash dot line) show how TN concentrations change if the mid-summer breach is performed again. The simulation was re-run through the same 2003 spring-to-fall period in order to investigate how the mid-summer breaching would affect water quality starting the following spring. These results are presented also in Figures VIII-3 (salinity) and VIII-4 (TN). The final salinity of the 2003 mid-summer breach is 25.7 ppt. The salinity drops through the winter to 23.3 ppt, at which point the spring (2004) breach is made. Assuming that the spring and mid- MASSACHUSETTS ESTUARIES PROJECT 90 summer breaches of the following year are as successful as the actual 2003 spring breach, the simulation shows that salinities never drop below 25 ppt after the spring, and average 27.4 ppt over the course of the entire simulation period. A similar improvement in the TN concentration in the following year was found, with the simulated spring level set to 0.82 mg/L. This starting concentration was derived using the difference in the TN concentrations computed at the end of the 2003 simulations with and without the mid-summer breach. This difference was determined to be 0.42 mg/L, and was assumed to carry through to the simulated 2004 spring. This 0.42mg/L difference was subtracted from the measured 2003 pre-breach concentration of 1.24 mg/L to arrive at the modified starting concentration of 0.82 mg/L.. Simulation results from the second consecutive year with a mid-summer breach show that the TN concentration never rises above 1.00 mg/L, and that the average TN concentration is 0.64, which is a 0.13 mg/L improvement over average conditions computed for the 2003 season without a mid-summer breach. Model results indicate that water quality improvements that may provide more stable environment for flora and fauna is possible with the addition of a successful mid-summer breach. Data indicate that openings as short as six days are sufficient to provide sufficient tidal flushing and raise salinity levels near 30 ppt. Pond salinity is a useful indicator of breach success, as opposed to the duration of the opening. With the mid-summer breach, it should be possible to maintain salinities above 25 ppt and TN concentrations below 1.00 mg/L. A significant improvement in the nitrogen related health of Sesachacha Pond infaunal animal habitat would result from the above modeled addition of a mid summer opening. It would be possible to use the monthly monitoring data to indicate when the mid-summer breach should occur. The primary indicator would be when the pond salinity drops below 25 ppt. The secondary indicator would be when the pond TN concentration rises above 0.95 mg/L. If this strategy is followed in the future, the result would be year-round salinities above 22 ppt and TN concentrations below 1.00 mg/L. It is important to note that the modeled maximum and average TN levels are likely conservative estimates as they do not include potential reductions in the rate of sediment nitrogen regeneration often associated with the lowering of nitrogen enrichment of embayment waters. It should be noted that the above mentioned management scenarios oriented around altering the timing of breaches of the barrier beach, effective as these may be, are contingent on the ability of the Town of Nantucket to obtain necessary permitting of such actions. Breaching of the barrier beach is necessarily subject to compliance with applicable federal, state and local statutes and regulations. MASSACHUSETTS ESTUARIES PROJECT 108 VIII. CRITICAL NUTRIENT THRESHOLD DETERMINATION AND DEVELOPMENT OF WATER QUALITY TARGETS VIII.1. ASSESSMENT OF NITROGEN RELATED HABITAT QUALITY Determination of site-specific nitrogen thresholds for an embayment requires integration of key habitat parameters (infauna and eelgrass), sediment characteristics, and nutrient related water quality information (particularly dissolved oxygen and chlorophyll). Additional information on temporal changes within each sub-embayment of an estuary and its associated watershed nitrogen load further strengthen the analysis. These data were collected to support threshold development for the Hummock Pond Estuarine System by the MEP and were discussed in Chapter VII. Nitrogen threshold development builds on this data and links habitat quality to summer water column nitrogen levels from the baseline Water Quality Monitoring Program conducted by Town staff and by staff and graduate researchers at and with analytical support from the Coastal Systems Analytical Facility at SMAST-UMass Dartmouth. Determination of site-specific nitrogen thresholds for an embayment requires integration of key habitat parameters (infauna and eelgrass), sediment characteristics, and nutrient related water quality information (particularly dissolved oxygen and chlorophyll a). Additional information on temporal changes within each sub-embayment and its associated watershed nitrogen load and geomorphological considerations of basin depth, stratification and functional type further strengthen the analysis. These data were collected to support threshold development for the Hummock Pond Estuarine System by the MEP Technical Team and were discussed in Chapter VII. Nitrogen threshold development builds on this data and links habitat quality to summer water column nitrogen levels from the long-term baseline Water Quality Monitoring Program conducted by the Town of Nantucket, with technical guidance and analytical support from the Coastal Systems Program at SMAST-UMass Dartmouth. The Hummock Pond Estuary is comprised of two major functional units, each with different levels of habitat quality, both are brackish (varying from 4-8 ppt). The main basin of Hummock Pond (e.g. the drown valley formed perpendicular to the barrier beach) which is generally closed to tidal exchange, and opened by breaching the barrier beach twice per year for pond management. Hummock Pond is a shallow narrow "finger pond" with moderate- significant impairment of benthic animal habitat and no historic eelgrass coverage. The second unit, Head of Hummock, is a man-altered basin which was once a freshwater kettle pond which has a channel to Hummock Pond which now allows salt water to enter. Head of Hummock supports severely degraded benthic animal habitat and no historic eelgrass coverage. The salinity of Head of Hummock and possibly Hummock Pond are at the limit for grow of eelgrass (5 ppt) consistent with the lack of eelgrass coverage historically. There is a clear gradient in infaunal habitat quality from severely degraded conditions in Head of Hummock to the lower main basin of Hummock Pond adjacent the barrier beach having the highest quality habitat. Part of the MEP assessment of the Hummock Pond Estuarine System was confirmation that the critical parameter controlling habitat quality is nitrogen, hence managing nitrogen enrichment would result in restoration of observed impairments. Analysis of inorganic N/P molar ratios within the water column of the Hummock Pond Estuarine System are consistent with virtually all of the estuaries in southeastern Massachusetts and New England in that nitrogen is the critical nutrient to be managed. The measured Redfield Ratio (inorganic N/P) ranges from 3.6-5.2 within the main basin and 1.8 within Head of Hummock. These data and the low concentration of inorganic nitrogen (~0.03 mg L-1) indicate that nitrogen additions will increase phytoplankton production, organic matter levels and turbidity within this system. MASSACHUSETTS ESTUARIES PROJECT 109 Increased phytoplankton and organic matter levels increase oxygen consumption within the waters and sediments and increase the extent of oxygen depletion and habitat impairment. It should be noted that nitrogen enrichment occurs through two primary mechanisms, high rates of nitrogen entering from the surrounding watershed and/or low rates of flushing due to restriction of tidal exchange with low nitrogen offshore waters. The Hummock Pond Estuary has seen increasing nitrogen loading from its watershed from shifting land-uses and due to coastal processes along its barrier beach, it is only periodically opened to tidal exchange. Fundamentally, restrictions of tidal exchange increase the sensitivity of an estuary to nitrogen inputs. Decreasing watershed nitrogen inputs or increasing tidal flushing will reduce nitrogen enrichment and its impacts. The present distribution and level of benthic animal habitat quality observed within the estuary is consistent with degree of nitrogen enrichment, and its resulting increase in phytoplankton biomass, organic matter and oxygen levels. All of the habitat indicators are consistent with the above assessment of the whole of the Hummock Pond System (Chapter VII). At present, eelgrass beds are not present in the Hummock Pond Estuary. The absence of eelgrass beds within Hummock Pond is expected given the measured levels of nitrogen enrichment and resulting chlorophyll a and dissolved oxygen. Total nitrogen levels (TN) within the lower basin have mean summer time levels >0.7 mg N L-1 compared to the levels in other similarly configured southeastern Massachusetts estuarine basins currently supporting eelgrass, 0.35-0.45 mg N L-1 (range of Cape Cod systems). Other key water quality indicators, dissolved oxygen and chlorophyll a, show similar levels of enrichment with chlorophyll levels averaging 9 to 33 ug L-1 in lower and upper reaches of main basin. Given the sensitivity of eelgrass to declining light penetration resulting from nutrient enrichment and secondary effects of organic enrichment and oxygen depletion, the lack of eelgrass habitat within Hummock Pond is consistent with observed eelgrass habitat and areas of loss in numerous other estuaries throughout the region. While Hummock Pond lacks eelgrass habitat, benthic animal habitat is also a critical estuarine resource and it is impaired throughout the Hummock Pond Estuary. Benthic animal habitat is generally has a higher tolerance for nitrogen enrichment than eelgrass, as unlike eelgrass, benthic animals do not require light for growth and therefore higher levels of turbidity and phytoplankton biomass are tolerated. Infauna habitat quality is the primary habitat for management of the basins comprising eh Hummock Pond Estuary. The is also no evidence that Hummock Pond supported eelgrass coverage over the past 60 years. Review of historic maps and information that indicate that none of the basins comprising the Hummock Pond Estuary were capable of supporting eelgrass historically. First, Head of Hummock appears to have been connected to Hummock Pond via an artificial channel, therefore it is a transformed freshwater kettle pond, rather than a natural estuarine basin. As such, it would not have historically supported eelgrass. In addition, a review of available records did not reveal any evidence of eelgrass beds in the main basin of Hummock, most likely due to its dynamic inlet resulting in periodic loss of tidal exchange, historically and today, and resulting poor water quality. Historical eelgrass beds have not been found in other embayments with similar inlet closures, throughout the region, although ephemeral patches may occur during periods of prolonged or frequent tidal exchange (e.g. Tisbury Great Pond). Equally significant, under present salinity conditions, Head of Hummock is below the lowest salinity where eelgrass is found to grow (5 ppt), and Hummock Pond is periodically below or just above that level as well. Only at higher salinity levels would eelgrass colonization even be possible in this system and the nature of the inlet makes this occurance unlikely over any prolonged period.. It should also be noted that eelgrass beds throughout the regions are typically found at salinities within the 20-32 ppt range. MASSACHUSETTS ESTUARIES PROJECT 110 The Weed Study conducted by the Hummock Pond Association provides additional support for the prolonged low salinity of the waters in Head of Hummock and in the upper reach of the main basin of Hummock Pond, as many of the plants found have a low tolerance for salt water, generally less than the 5 ppt lower limit for eelgrass growth. Based upon these multiple lines of evidence, it appears that the basins comprising the Hummock Pond Estuary have not historically supported eelgrass beds or significant eelgrass habitat. Therefore, the threshold analysis for this system is necessarily focused on restoration/protection of infaunal animal habitat. Overall, the main basin of Hummock Pond is supporting a gradient in impairment from significantly impaired in the upper basin to moderately impaired in the lowest reach near the barrier beach. However, the tributary basin of Head of Hummock is currently supporting severely degraded habitat with no marine invertebrates only 2 species of insect larvae. Head of Hummock contains lower salinity water than the Hummock Pond main basin, likely due to its function as a drown kettle pond in the uppermost reach of the system. As such, Head of Hummock is the focus of groundwater discharge from the watershed and as the entire system is usually without tidal currents, mixing is limited. The salinity of Head of Hummock is low enough (<5 ppt) to influence the plant and animal communities that colonize, although estuarine benthic animal communities are fully capable of colonizing at salinities to 3 ppt. However, the Head of Hummock basin is virtually devoid of benthic animals, only supporting 2 insect larval species and no estuarine infauna. The likely results from the periodic anoxic events during summer in this basin. In contrast, the main basin of Hummock Pond in areas with similar salinities, currently support benthic anaimal communities. Therefore, the loss of benthic animals in Head of Hummock appears to be related to the high organic matter loading and periodic anoxia, rather than the low salinity (as was also observed in Oyster Pond, Falmouth). The main basin of Hummock Pond is presently supporting significantly impaired benthic animal habitat in its upper reaches as seen by the low numbers of species (4) and individuals (~90), with a moderate to low diversity (1.6). Significantly, stress indicator species (Capitellids, Tubificids) are not prevalent at any station within the main basin, comprising a minor fraction (<2%) of the population. Benthic habitat quality improves moving toward the barrier beach with the lower main basin having moderat numbers of species (8) and individuals (~120) but still moderate to low diversity (1.8). Similarly, the in the basin nearest the barrier beach, habitat is only showing moderate impairment with moderate numbers of species(10) and individuals (~200) and diversity (2.3). Both the values of the habitat indicators and the gradient in quality from upper to lower estuary, are consistent with the observed levels of oxygen depletion (periodic anoxia in Head of Hummock), organic enrichment (chlorophyll a at 40-60 ug L-1 in Head of Hummock and <10 ug L-1 in the lower main basin of Hummock Pond. The gradient in habitat quality also parallels the TN levels fo 1.6 mg N L-1 declining to ~0.7 mg N L-1 in the lower main basin. This range in TN has been found to support only impaired benthic animal habitat in open water systems throughout s.e. Massachusetts. Further evidence of impairment of the main basin of Hummock Pond is the dominance of the benthic community by amphipods (Ampelisca, Leptocheiris), which are typical of transitional environments (between high and low quality habitat).. In addition to the watercolum indicators, the lower basin of Hummock Pond has accumulations of macroalgae along the margins of the basin which are associated with poor benthic habitat. Macroalgae can have a "smothering" effect on benthic animals as observed in the most extreme situation of the main basin of Waquoit Bay. The accumulations result in low oxygen at the sediment surface resulting in decline of benthic populations. These MASSACHUSETTS ESTUARIES PROJECT 111 accumulations in the lower main basin provide additional stress to benthic communities and are consistent with the observed TN level and observed benthic communities. The benthic animal communities within the basins of the Hummock Pond System were compared to high quality environments, such as the Outer Basin of Quissett Harbor, which provides additional confirmation of impaired habitat. The Outer Basin of Quissett Harbor supports benthic animal communities with >28 species, >400 individuals with high diversity (H' >3.7) and Evenness (E >0.77). Similarly, outer stations within Lewis Bay in Barnstable currently support similarly high quality benthic habitat as seen in the numbers of individuals (502 per sample), number of species (32), diversity (3.69) and Eveness (0.74). Equally important these communities are not consistent with nutrient enrichment being composed of a variety of polychaete, crustacean and mollusk species, as opposed to stress tolerant small opportunistic oligochaete worms (tubificids, capitellids). These habitats represent the highest quality and exist in well flushed basins and have consistently high oxygen and low chlorophyll a levels and low amounts of organic enrichment. While these represent a theoretical goal for restoration, the reality of the tidal flushing characteristics of Hummock Pond must also be taken into account, as with other periodically opened estuaries (Edgartown Great Pond, Tisbury Great Pond). Overall, the pattern of infaunal habitat quality throughout the Hummock Pond Estuary is consistent with measured dissolved oxygen concentration, chlorophyll, nutrients and organic matter enrichment in this system (Table VIII-1). Classification of habitat quality necessarily includes the structure of the specific estuarine basin and its tidal characteristics (continuously or periodically opened to tidal flows). Based upon this analysis it is clear that the upper regions of the estuary, Head of Hummock and upper main basin of Hummock Pond, are severely degraded and significantly impaired, respectively, by nitrogen and organic matter enrichment while the lower main basin is presently supporting moderately impaired benthic animal habitat. The proximate cause of impairment is organic matter enrichment and oxygen depletion, stemming ultimately from nitrogen enrichment. Total nitrogen levels within the upper basin (Head of Hummock) >1.0 mg N L-1, a level associated with impoverished and degraded benthic animal habitat in other s.e. Massachusetts estuaries. Benthic communities have been found to be impaired at TN levels lower than found in Hummock Pond, e.g. Falmouth Inner Harbor, 0.58 mg TN L-1, Fiddlers Cove and Rands Harbor, 0.56 mgTN L-1 and 0.57 mgTN L-1, respectively. It appears that Hummock Pond is well beyond its threshold TN level to support healthy benthic habitat. As there is no evidence of present or historic eelgrass beds within the Hummock Pond Estuary, management actions should focus on restoration of benthic animal habitat. VIII.2 THRESHOLD NITROGEN CONCENTRATIONS The approach for determining nitrogen loading rates that will support acceptable habitat quality throughout an estuary and salt pond is to first identify a sentinel location within the embayment and secondly, to determine the nitrogen concentration within the water column at that site which will result in the desired habitat quality. The sentinel location is selected such that the restoration of that one site (or group of sites) will necessarily bring the other regions of the system to acceptable habitat quality levels. Once the sentinel site and its target nitrogen level are determined (Section VIII.2), the Linked Watershed-Embayment Model is used to sequentially adjust nitrogen loads until the targeted nitrogen concentration is achieved (Section VIII.3. MASSACHUSETTS ESTUARIES PROJECT 112 Table VIII-1. Summary of nutrient related habitat quality within the Hummock Pond Estuary, Town of Nantucket, MA, based upon assessments detailed in Section VII. Head of Hummock is a kettle pond opened via a channel to the upper main basin of Hummock Pond. Hummock Pond is periodically opened to tidal flows, but receives salt water in storm overwash of the barrier beach. Health Indicator Hummock Pond Estuarine System Head of Hummock Basin Hummock Pond Main Basin Dissolved Oxygen SI/SD1 H/MI2 Chlorophyll SI3 SI/MI4 Macroalgae --5 SI6 Eelgrass --7 --8 Infaunal Animals SD9 MI/SI 10 Overall: SD11 MI/SI12 1- mooring oxygen <3 mg/L 31%, with multiple day anoxic events, daily excursion 3-5 mg/L, but extended oxygen levels about air saturation (10-15 mg/L versus 8 mg/L) consistent with eutrophic conditions. D.O. less than 4 mg/L is stressful to estuarine organisms. Sediments anoxic-sulfidic mud. 2- mooring oxygen: moderate daily excursions in oxygen levels in upper and lower reach of main basin, generally ranging from 6 mg/L to 8 mg/L, rarely to 5 mg/L; <6mg/L 6% and 5% of record respectively. 3- levels moderate/high, mooring average 34 ug L-1, >25ug L-1 85% of record; blooms >60 ug L-1; WQMP: high chlorophyll a, summer averages of 20-30 ug L-1, averages >10 indicate N enrichment 4- levels moderate/high, in upper main basin mooring average 33 ug L-1, >25ug L-1 75% of record; strong gradient to lower main basin where mooring average was only 8 ug L-1, and >10 ug L-1 for 16% or record. Possibility of Head of Hummock influencing upper main Hummock Pond basin. WQMP: shows similar gradient of high chlorophyll a upper main basin declining to 9 ug L-1 in lower main basin. 5- drift algae generally absent, some areas of brackish water macrophytes in shallow margins, sediments of basin are black anoxic sulfidic unconsolidated muds, highly enriched with organic matter. 6- drift algae generally not observed in upper half of basin, but consistently in shallow margins of lower half of main basin; oxidized surface to sediments, and varying levels of medium to fine sand. 7- artificial brackish water basin, no historical evidence of eelgrass beds 8- periodically breached basin, no historical evidence of eelgrass beds, but possibly few sparse patches 9- low numbers of species (2), individuals (<100) diversity and Evenness. Appears that salinity and freshwater inflow areas have shifted bottom community toward freshwater community. 10- sparse stress indicator species, but generally dominated by intermediate organic enrichment species, amphipods (Ampelisca, Leptocheiris). Clear gradient: upper HP main basinmidbarrier beach: increasing # species (4,8,10), numbers (~100 -> ~200), diversity (1.6 -> 2.3) and moderate to good Evenness. Near inlet mollusks, crustaceans, polychaetes, but at levels lower than high quality areas. 11- Severely degraded benthic animal habitat, present community indicative of brackish highly stressed habitat, consistent with periodic anoxia & frequent hypoxia & high phytoplankton biomass (>30 ug L-1). Low species and organism numbers and anoxic sulfidic fluid muds indicative of unstable organic enriched system. 12- Moderately impaired to significantly impaired benthic animal habitat, upper and lower reaches, respectively; community indicates gradient in impairment from the uppermost to the lowermost basin which mirrors the gradient in chlorophyll a and TN. Oxygen conditions generally show little to modest depletion, generally to 5-6 mg/L. Benthic community dominated by amphipods indicative of a system impaired by nitrogen and organic matter enrichment, few stress indicators (capitellids, tubificids). H = High quality habitat conditions; MI = Moderate Impairment; SI = Significant Impairment; SD = Severely Degraded; -- = not applicable to this estuarine reach WQMP: Water Quality Monitoring Program MASSACHUSETTS ESTUARIES PROJECT 113 Determination of the critical nitrogen threshold for maintaining high quality habitat within the Hummock Pond Estuary is based primarily upon the nutrient and oxygen levels and current benthic community indicators, as there is no history of eelgrass colonization of the 2 major basins. Given the information on a variety of key habitat characteristics, it is possible to develop a site-specific threshold, which is a refinement upon more generalized threshold analyses frequently employed. The Hummock Pond Estuary presently shows a moderate to significant impairment of its benthic animal habitat in its main basin and severely degraded habitat in Head of Hummock and is clearly beyond its nitrogen threshold (i.e. the level of nitrogen a system can tolerate without impairment). The indications of impairment to infaunal animal habitat are supported by the observed levels of oxygen depletion and clearly enhanced chlorophyll a levels, sediment organic matter enrichment and macroalgal accumulations, are similar to other estuaries with similar levels of nitrogen enrichment. A Sentinel station was established for the Hummock Pond Estuary for development of a nitrogen threshold target that when met will restore benthic animal habitat throughout its estuarine reach. Since there is a relatively small gradient in nitrogen in the main basin, the sentinel station was selected at the basin’s mid point, which reflects the average conditions within Hummock Pond. The uppermost station was not selected as it appears to be effected by outflows from Head of Hummock and not reflective of typical conditions within the main basin. Sentinel Station for Head of Hummock was established at the long-term monitoring station 3 (HUM-3). The main basin is typically non-tidal except for 2 brief periods per year, so the main basin supports only a modest gradient in nitrogen. The average total nitrogen levels at the sentinel station are currently 0.72 mg N L-1. It should be noted that the freshening of Head of Hummock must be managed as part of restoration of benthic animal habitat in this estuary. This TN level is comparable to other estuarine basins throughout the region that show similar levels of oxygen depletion, organic enrichment and moderately impaired benthic animal habitat. TN levels >0.70 mg N L-1 are generally characterized as having significantly impaired benthic habitat, phytoplankton blooms and periodic hypoxia and even fish kills (e.g. finger ponds in Falmouth). Benthic animal habitat is typically impaired even at TN levels of 0.58 mg TN L-1 (Falmouth Inner Harbor), 0.56 mgTN L-1 (Fiddlers Cove) and 0.57 mgTN L-1 (Rands Harbor). Given that in numerous estuaries it has been empirically previously determined that 0.500 mg TN L-1 is the upper limit to sustain unimpaired benthic animal habitat (Eel Pond, Parkers River, upper Bass River, upper Great Pond, upper Three Bays, as well as the 7 inner basins of Pleasant Bay) this level is deemed most appropriate for restoration of benthic animal habitat within Hummock Pond. Watershed management to meet the restoration threshold for benthic animal habitat is the focus of the nitrogen management threshold analysis (Section VIII.3). VIII.3 DEVELOPMENT OF TARGET NITROGEN LOADS After developing the dispersion-mass balance model of Hummock Pond to simulate conditions that exist as a result of present management practices, the model was used to simulate a modified management approach that could be followed to improve water quality conditions in the pond year-round. With a goal of seeking further improvements in water quality conditions in the Pond, an alternate management scheme was modeled using the previously developed dispersion-mass balance model. The main goal of this proposed management scenario is to prevent time averaged pond-wide TN concentrations in the pond from rising above 0.50 mg/L in the main basin of the Pond (at monitoring station HUM-3) during the summer months, when benthic MASSACHUSETTS ESTUARIES PROJECT 114 regeneration and algae production is greatest. A way to achieve these goals is to reduce the watershed loading to the pond, together with an additional mid-summer breach. Watershed loading was reduced from present conditions until the time averaged TN concentration at station HUM-3 would remain below 0.50 mg/L during a complete breaching cycle, where the pond is open to tidal flushing for at least four days and subsequently closed for 60 days. The resulting threshold septic loading is presented in Table VIII-1. A 82% reduction from present conditions together with a functioning breach duration of 4 days was required in the septic load to the pond to achieve the threshold requirements. In this scenario 80% of the septic load is removed from the main watershed of the pond, and 95% was removed from the smaller Head of Hummock sub-watershed. This septic load change results in a 63% change in the total watershed load to the pond, as shown in Table VIII-2. A tabulation of all the loads to the pond is provided in Table VIII-3. The benthic loading term is effected by the change in watershed load. The method described in section VI.2.5.1 was used to adjust the benthic regeneration load to the pond for threshold conditions. Table VIII-2. Comparison of sub-embayment septic loads used for modeling of present and modeled threshold loading scenarios of Hummock Pond. These loads do not include direct atmospheric deposition (onto the sub-embayment surface) or benthic flux loading terms. sub-embayment Present load (kg/day) threshold (kg/day) threshold change Hummock Pond main basin 8.436 1.687 -80.0% Head of Hummock 1.366 0.068 -95.0% Total 9.801 1.755 -82.1% Table VIII-3. Comparison of sub-embayment watershed loads used for modeling of present and modeled threshold loading scenarios of Hummock Pond. These loads do not include direct atmospheric deposition (onto the sub-embayment surface) or benthic flux loading terms. sub-embayment Present load (kg/day) threshold (kg/day) threshold change Hummock Pond main basin 11.195 4.446 -60.3% Head of Hummock 1.682 0.383 -77.2% Total 12.877 4.829 -62.5% MASSACHUSETTS ESTUARIES PROJECT 115 Table VIII-4. Sub-embayment and surface water loads used for total nitrogen modeling of threshold conditions for Hummock Pond, with total watershed N loads, atmospheric N loads, and benthic flux. sub-embayment watershed load (kg/day) direct atmospheric deposition (kg/day) benthic flux net (kg/day) Hummock Pond main basin 4.446 1.918 0.109 Head of Hummock 0.383 0.208 0.473 Total 4.829 2.126 0.582 The effect on TN concentrations through the course of the summer of the threshold management scenario suggested for Hummock Pond is presented in Figure VIII-1. For the 64- day period shown in Figure VIII-1, the time averaged TN concentration is 0.50 mg/L at the HUM- 3 monitoring. It is important to note that the threshold scenario provided as part of this report is one of many possible loading and breaching combinations that could work to improve water quality in the Pond. If the inlet remained open for a period longer than 4 days, the threshold concentration could likely be achieved with less watershed load reduction. Figure VIII-1. Time series of modeled TN concentrations at monitoring station TGP 7 from the threshold model scenario where the pond is breached in late May for four days. MASSACHUSETTS ESTUARIES PROJECT 116 IX.1 FRESH WATER HEAD OF HUMMOCK In reviewing historic maps and examining the topography around Head of Hummock, it appears likely that this small brackish kettle pond was artificially connected to the Main Basin of Hummock Pond. The appearance is that Head of Hummock was once fresh water and with the channel and subsequent actions, the pond is now brackish, although consistently less saline than the main basin of Hummock Pond. Head of Hummock remains moderately isolated from Hummock Pond, with outflow of freshwater and some salt water inflows, such as due to storm events. Head of Hummock, as a kettle pond, is deeper than the outer basins (>3 m versus generally 1-2 m). It is highly nitrogen enriched and its sediments reflect its depth and depositional nature, being black fluid muds, which are anoxic and sulfidic and devoid of benthic animals with net nitrogen release to the overlying waters, seen in many kettle ponds opened to salt water inputs (Oyster Pond, Falmouth, Areys Pond, Orleans). At present, Head of Hummock is a brackish estuarine basin whose nutrient related water quality and habitat quality is dominated by nitrogen availability. This is typical of estuarine systems throughout the region. However, as it appears that this kettle pond was artificially connected to Hummock Pond and now allows input of salt, as part of the MEP restoration analysis, a preliminary analysis of restoring freshwater conditions was undertaken. The concept is that freshwater systems are biogeochemically structured such that phosphorus is the nutrient of management concern and there are multiple “in pond” phosphorus controls available should phosphorus levels result in eutrophic conditions. More important, freshwater systems remove nitrogen that passes through them, lowering nitrogen loads to downgradient estuarine basins. Therefore, the management alternative to be evaluated is to isolate Head of Hummock from Hummock Pond, allowing freshwater outflow for pond level control and fish passage (should it become necessary). This restoration of freshwater conditions would allow Head of Hummock restoration as a freshwater pond, and would provide a reduction in nitrogen load to the main basin of Hummock Pond as part of its restoration of water quality and habitat. To quantify the possible water quality benefits that would result from returning Head of Hummock to a fresh water pond, a model scenario was developed by modifying the grid developed for existing conditions. Though Head of Hummock is removed from the tidal reach of the system, its watershed would continue to be a nitrogen source to the main basin of Hummock Pond, but with some additional removal by the now freshwater pond. The amount of load that passes to Hummock Pond is controlled by the attenuating capacity of the modified fresh water basin. Based on TN attenuation observed in freshwater ponds with similar depths and retention times throughout the region, it is estimated that Head of Hummock would be able to attenuate 50% of the TN load entering the pond from its watershed. At present, Head of Hummock as a brackish water basin transforms significant amounts of nitrogen but ultimately passes nitrogen to the downgradient main basin. The changes that result from this modification are large enough to cause noticeable improvements throughout the main basin of Hummock Pond, particularly in how it flushes and how TN concentrations increase during periods when tidal exchange is closed off. However, these changes are not large enough to fully restore the habitat quality of Hummock Pond. The flushing rate of the entirety of Hummock Pond decreases from 4.2 to 3.5 days, an improvement of 17%. The average TN concentration over the entire 64-day simulation period (Figure IX-1) decreases by 0.04 mg/L, which represents an 8% decrease (over open ocean background concentration). MASSACHUSETTS ESTUARIES PROJECT 117 Figure IX-1. Modeled TN concentrations in the main basin of Hummock Pond (at monitoring stations HUM-3) after a simulated four-day open breach and its subsequent closure, with an initial concentration of 0.60 mg/L, showing the N attenuation effect of changing Head of Hummock into a fresh water pond, with no other change in watershed loading. IX.2 FRESH WATER HEAD OF HUMMOCK THRESHOLD N LOADING Although the freshwater Head of Hummock scenario is not enough by itself to achieve the N load reductions required to meet the threshold set for the pond, it is possible that it could be used together with additional watershed N load reductions. The N load reduction needed to meet the threshold would be less than the scenario provided in Chapter VIII since Head of Hummock attenuates 50% of the incoming load as a freshwater pond. In addition, restoring freshwater conditions to Head of Hummock also allows separate restoration of this kettle basin in parallel with the restoration of Hummock Pond. The N loading scenario developed using the freshwater Head of Hummock is presented in Tables IX-1 and IX-II. The freshwater Head of Hummock scenario requires 7% less reduction in total N load and ~9%reduction in wastewater load to meet the threshold. The plot of model output over the 64-day simulation period is shown in Figure IX-II. MASSACHUSETTS ESTUARIES PROJECT 118 Table IX-1. Comparison of sub-embayment watershed loads used for modeling of present (2003), present 2007, build-out, and no-anthropogenic (“no-load”) loading scenarios of Hummock Pond. These loads do not include direct atmospheric deposition (onto the sub-embayment surface) or benthic flux loading terms. sub-embayment Present load (kg/day) Threshold Scenario (kg/day) Threshold Scenario change FW Head of Hummock (kg/day) FW Head of Hummock % change Hummock Pond main basin 11.195 4.446 -60.3% 4.868 -56.5% Head of Hummock 1.682 0.383 -77.2% 0.840 -50.0% Total 12.877 4.829 -62.5% 5.708 -55.7% Table IX-2. Build-out conditions sub-embayment and surface water loads used for total nitrogen modeling of Hummock Pond, with total watershed N loads, atmospheric N loads, and benthic flux. sub-embayment watershed load (kg/day) direct atmospheric deposition (kg/day) benthic flux net (kg/day) Hummock Pond main basin 4.868 1.918 0.119 Head of Hummock 0.840 0.104 - Total 5.708 2.022 0.119 Figure IX-2. Modeled TN concentrations in the main basin of Hummock Pond (at monitoring stations HUM-3) after a simulated four-day open breach and its subsequent closure, with an initial concentration of 0.60 mg/L, for the alternate Threshold N loading scenario that includes the attenuation effect of turning Head of Hummock into a fresh water pond. OUR SERVICES WasteO ptionsNantucket,LLCoperatesandmanagestheTow n ofNantucket’s solidw astemanagementandrecyclingfacility, w hichincludesoperatingthe Tow n’snew state-of-the-artlinedcelllandfillandmaterialsrecyclingfacility,100 ton perdayco-compostingfacility,aconstruction anddemolition materials recyclingfacility,miningoftheoldunlinedlandfillandprocessingleaf/yardw aste, YOUR EMAIL ADDRESS LEARN MORE ABOUT HOW W E ARE KEEPING NANTUCKET GREEN. LEARN MORE      SERVICES H ISTO RY AWARDS NEWS& UPDATES RECYCLING TIPS CO NTACTUS Page1 of1 2WasteOptions,Inc.|Nantucket’ssolid wastemanagementand recyclingfacility 9/5/201 4http://wasteoptions.com/ clean w ood, brush andvariousrecyclablecommodities.Thisintegratedfacility handlestheentirew astestream,includingmunicipalw aste, sludge,allrecyclables, construction & demolitionw aste,metals, w oodw aste,yardw aste, furniture, tires, batteries,appliances,textiles,sew agesludge, andanimalmanure.Yep,w edo itall. Inthecalendaryear2012,thefacilityprocessedapproximately32,000 tonsof material,includingrecyclables. Wedispose,recycle, andreuseallofthew asteon Nantucketto keepourisland clean andpristineat areasonablecostto theresidentsofNantucket. Weutilize proprietaryknow -how to turn w hatw asonceanembarrassingproblem for Nantucketinto aw orld-classsolidw asteprocessingfacilityw iththehighest recycleratein thenation. Theestimatedamount ofmaterialsrecycledanddivertedfrom thelandfillexceeds 92% . O urfacilitycombinestraditionalrecyclingofmetals,plastic,paper, cardboardandglassw ith therecyclingofmoredifficultitemssuch astires, refrigerators,stoves, mattresses,sofas,chairs,clothingandshoes. Residentscandropofforpickup usedbelongingssuchasclothing,booksortoys freeofchargeat theTake-It-or-Leave-It-Sw apfacility.Unclaimeditemsaresent forrecycling.Additionally, construction & demolitionw aste,w oodw asteandyard w asteareprocessedandrecycled.TheTake-It-or-Leave-It-Sw apfacilityis adjacent to theMaterialsRecyclingFacility(MRF)andoperatedbytheTow n. Astate-of-the-art, enclosedin-vesselcompostingsystemconvertsorganicw astes andmunicipalbiosolidsinto valuabletopsoil, w hichresultsin no morethan20% of allincomingmaterials(processedthrough theCo-CompostingFacility)being placedinthelinedcell.The“residue”from thecompostingoperationisinertand non-polluting,andisbaledanddepositedinto astate-of-the-artlinedcellto protect theaquifer. HOW W ECLEANNANTUCKET: ResidentialWaste:Werecycleordisposeofresidentialw astew ithout separately billingresidentsforourservices. LeafandYardWaste:Treesandshrubsarechippedalongw ith w oodextracted from theConstruction & DemolitionFacility.Thismaterialismixedw iththe compost producedfrom theCo-CompostingFacilityandisalso usedasmedia materialfortheCo-CompostingFacilitybiofiltersystem orasmulch. SERVICES H ISTO RY AWARDS NEWS& UPDATES RECYCLING TIPS CO NTACTUS Page2 of1 2WasteOptions,Inc.|Nantucket’ssolid wastemanagementand recyclingfacility 9/5/201 4http://wasteoptions.com/ TheTake-It-or-Leave-It-SwapFacility:Residentscan drop offorpickupused belongingssuch asclothing,booksortoys,freeofcharge. Unclaimeditemsare sent forrecyclingafter3 days. Hardto ManageWaste:Bulkyitemssuchasmattresses,boxsprings, rugsand sofascan beleft at theWasteTrailer andarethenshippedto arecyclingfacility thatremovesthecotton, w oodandothercomponentsto berecycledandreused. MaterialsRecyclingFacility (MRF):Recyclablessuchascardboard,new spaper, magazines, mixedpaper,mixedplastics, steelandaluminum aresorted, baled, storedandshippedto themainland.G lassiscollectedseparatelyattw o designated areas(commercialandnon-commercial). Co-Composting:O urproprietaryBedminsterco-compostingtechnology– an enclosed,controlled-environmentrotatingkilntechnology– isusedto recycle organicsbyprocessingmunicipalsolidw asteandmunicipalsew agesludge together, utilizingnaturalbiologicalprocessesto produceacompost endproduct thatcan beusedforlandscaping, landreclamation, asasoiladditive,andforlandfill covers. Thefacilityproduceshighlybeneficialorganiccompostandsoilsw hich meet themost stringent standardsfor unrestrictedusebytheMassachusetts DepartmentofEnvironmentalProtection andtheUnitedStatesEnvironmental Protection Agency. Thisrich, organiccompostismadeavailablefreeofchargeto Islandresidentsatthefacility,savingmoneyonthosegardeningprojects. Additionally,bycompostingorganicsinsteadofplacingthem inthelandfillw here thenaturaldecomposition processw ouldproducemethane,theWasteO ptions treatmentreducesgreenhousegasproductionandimprovestheenvironment. Construction& Demolition Waste:Constructionanddemolition(C&D)w asteis manuallysortedto extractrecyclablematerials.Thelargestsinglecomponent in thisw astestream isw ood. Clean,sourceseparatedw oodandpalletsgo to a chipper;theclean chippedw oodismixedw iththecompostorleaf/yardw asteand laterusedforbeneficialusessuchaslandscaping.O therrecyclablematerialssuch asmetalandcardboardareextractedfrom theC&D Wasteandrecycled. Non- recyclablematerialsareshippedoffislandandfurtherprocessedat facilitieson themainland. Remediation ofSite:Startingin1997 andpriorto theconstructionoftheCo- CompostingFacility,WasteO ptionsremediatedthesiteandreducedthefoot printoftheenvironmentallyunfriendlyandoutdatedunlinedlandfillpreviously operatedbytheTow n from 42 acresdow n to 22 acres.Part oftheremediation SERVICES H ISTO RY AWARDS NEWS& UPDATES RECYCLING TIPS CO NTACTUS Page3of1 2WasteOptions,Inc.|Nantucket’ssolid wastemanagementand recyclingfacility 9/5/201 4http://wasteoptions.com/ processincludedminingandshippingoffislandover250,000 tiresthatw ere buriedthroughout thesite.Through theseactions, WasteO ptionsprovided w elcomeprotectionfortheaquiferandsurroundingenvironmentallysensitive areas. UnlinedLandfill:WasteO ptionshasfurthercappedandclosed15.5 acresofthe 22 acresofthelandfill,w hichisow nedbytheTow n,that remainedatthetimethe Co-CompostingFacilityw asconstructed.Compost from theCo-Composting Facilityhasbeenusedto construct vegetation coverontopofthecappedareasof thelandfill.Priorto 2008, aportionofthe7 acreuncappedsection oftheold unlinedlandfillw asminedandrecyclablematerialsw ereextractedforfurther processing. Mining:In 2009,WasteO ptionsstartedacceleratedminingoftheoldunlined landfill.WasteO ptionshasminedan averageofapproximately100,000 cubic yardsperyear ofmaterialfrom thelandfill.Soilsthat passtheS-1/G W-1 soilclean upcriteria (every1,000 cubicyardsofmaterial)isreusedon sitefor new linedcell construction andsiteimprovements. SoilthatdoesnotpasstheS-1/G W-1 standardandresiduals(e.g., plastic)areplacedbackinto thelandfill.To date, WasteO ptionshasminedover400,000 cubicyardsofmaterial.Muchofthesoil minedthat meetstheS-1/G W-1 standardhasbeen usedto gradeandslopethe site,andto createstorm retentionpondson thebacksideofthenew linedcells,or isbeingstockpiledto beusedfor futurelinedcellconstruction. Themining operation hasfurtherreducedtheunlinedlandfillfromthe22 acresthatexisted w hen theCo-CompostingFacilityw ent into operationto lessthan 19 acres. LinedCell Landfills:WasteO ptions,w orkingw ith theTow n (w hichow nsthelined landfillcells),havedevelopedtw o new landfillcellsthat includea state-of-the-art linersystemusedforthedisposalofresidualsfromtheCo-CompostingFacility. All leachateiscollectedandtransportedto the Tow n’sWasteWaterTreatmentPlant. Thenew linedlandfillsareperiodicallyinspectedbytheMassachusetts DepartmentofEnvironmentalProtection forgasandgroundw atermonitoring, leachategeneration monitoring, leakdetectionandfillingrates. Miningiscurrentlybeingperformedinasectionoftheoldunlinedlandfillw herea futurelinedcelllandfillw illbeconstructed. Muchofthesoilminedfrom thelandfill miningoperationw illbeableto bereusedto help w iththefutureconstructionofa new linedcelllandfill.TheseactionsdefertheneedfortheTow n to capandclose thelandfill,andw illprovidesignificant savingsto theTow n. SERVICES H ISTO RY AWARDS NEWS& UPDATES RECYCLING TIPS CO NTACTUS Page4 of1 2WasteOptions,Inc.|Nantucket’ssolid wastemanagementand recyclingfacility 9/5/201 4http://wasteoptions.com/ W EDON’TCHASETHE AW ARDS, THEYCOMETOUS NATURALLY. AW ARD S Nantuckettopsinnation for recycling.Theislandw asrecognizedbyanational advocacygroup(G rassrootsRecyclingNetw ork)forobtaininga92 percent recyclingrate,knockingSan Francisco offitsperchasthetoprecyclingcommunity in thecountry. (O ctober2009) In1996, in conjunctionw ith WasteO ptions, “Nantucket commenced implementationofacomplexsolidw astedisposalprogramthatincorporated landfillclean-up, recyclingandcompostingto developthemostcompletew aste managementsystemintheCommonw ealth.” SERVICES H ISTO RY AWARDS NEWS& UPDATES RECYCLING TIPS CO NTACTUS Page5of1 2WasteOptions,Inc.|Nantucket’ssolid wastemanagementand recyclingfacility 9/5/201 4http://wasteoptions.com/ “W hilenot everycommunityinthestatemaypossesstheresourcestoinstitutea recycling andcomposting system asadvancedasNantucket’s,theycan certainly takeacuefrom theislandandtreat itshighrecycling ratesassomethingtostrive toward.”(August2009) ATAGLANCE …WASTEOPTIONS… ◦isthemost advancedmunicipalsolidwasterecyclingandprocessing facilityin theU .S. The estimatedamountofmaterialsrecycledanddivertedfrom landfilling nowexceeds92% . ◦isan integratedwasteprocessing andrecyclingfacilitywhichmaximizesthe abilitytorecycleanddivert materialsfrom being landfilled. ◦hasreducedthefootprint ofthelandfill to belowtheoriginalpermitted footprint. ◦usesaproprietary,state-of-the-art, enclosedin-vesselcompostingsystem, which convertsorganicwastesandmunicipalbiosolidsinto valuablesoil. ◦producescompostthat exceedsthequalitystandardsof boththeU .S. EnvironmentalProtectionAgencyandtheCommonwealthofMassachusetts. ◦wasthefirstcompostfacilitytoberegisteredforcarboncreditswith the Chicago ClimateExchangein 2009. ◦achievesthehighest recyclingrateintheCommonwealth of Massachusetts, savingtheislandmillionsofdollarsbyvastlyreducing the amountofwastethat mustbeshippedoff-island. WECONVERTYOURWASTE INTOVALUABLETOPSOIL. SERVICES H ISTO RY AW ARD S NEW S&U PD ATES RECYCLING TIPS CO NTACTU S Page 6 of 12Waste Options, Inc. | Nantucket’s solid waste management and recycling facility 9/5/2014http://wasteoptions.com/ HISTORY.With you since 1997 D uringthemid-1990’s, theevergrowing popularityandpopulation oftheisland placedincreasing strain on theIsland’sinfrastructure, particularlyasitrelatedto thetreatment ofsolidwaste.TheTown wasfacinga seriouscrisisoveritssolid wastehandlinganditsassociatedcosts.Itsunlinedlandfill,createdat theendof W orldW arII,wasamountain ofuncoveredgarbageandtrash.Seagullsswarmed thelandfillto feeduponthewaste.Thevolumeofwastefrom construction and demolitionprojectswasoverflowing thelandfill.TheTown wasfacing aserious dilemmaofhowto dealwith thehealth, environmentalandsafetyhazards resultingfromitshandling ofwaste,andtoprepareforthefutureneedsof the Town’swastedisposal. In1994, theCommonwealth ofMassachusettsmandatedthat Nantucketcloseits landfill,andthatitswastebeshippedoff-islandfor disposalonthemainland.If this hadoccurred,thetrashbillsforallislanderswouldhavequadrupled. In1997, theTown enteredinto apublic-privatepartnershipwithW asteO ptionsto remediatethelandfill site,managethelandfilloperation andrecyclingfacility,and toconstructandoperatea100 ton perdaycompost facility. O riginally,an interim operating agreementprovidedforan orderlytransition from theTown operations toW asteO ptions. Then, in 2000,whenthecompostfacilitywascompleted,W aste O ptionsbegan its25 yeartermofoperations. SERVICES H ISTO RY AW ARD S NEW S&U PD ATES RECYCLING TIPS CO NTACTU S Page 7 of 12Waste Options, Inc. | Nantucket’s solid waste management and recycling facility 9/5/2014http://wasteoptions.com/ Starting in 1997 andpriortotheconstructionofthecompost facility, W aste O ptionsremediatedthesiteandreducedthefoot print oftheoldunlinedlandfill from 42acresdown to 22acres.Part of theremediationprocessincludedmining andshipping off-islandover250,000 tiresthatwereburiedthroughout thesite. Subsequenttothestart-upoftheCo-CompostFacility, thepre-existinglandfill footprinthasbeenreducedafurther3+ acresfrom theacceleratedmining program. W asteO ptionsutilizeditsproprietaryknow-howtoturnanembarrassing problem fortheTownintoaworld-classsolidwasteprocessing facilitywith thehighest recycleratein thenation. Through itsoperation,W asteO ptionshasoperated,improved, andconstructed newfacilities, including anewstate-of-the-art linedlandfillcellforthemulti- stream wastemanagement facilitywhich hasmet andexceededtheexpectations oftheoriginal public-privatepartnership.TheNantucket SolidW asteRecycling andCompostingFacilityisthemost comprehensiveintheCommonwealth.That’s whatcomesfrom apublic-privatepartnership – weallbenefit. OURTREASUREISYOUR TRASH SERVICES H ISTO RY AW ARD S NEW S&U PD ATES RECYCLING TIPS CO NTACTU S Page 8 of 12Waste Options, Inc. | Nantucket’s solid waste management and recycling facility 9/5/2014http://wasteoptions.com/ NEWS & UPDATES.What's going on W ehavemadesignificant investmentsin improvingandrepairingour facilitytomaintainour world-classsolid wasteandrecyclingoperation righthereon Nantucket. H ere’swhat’sbeenhappening: BROWSE ALL NEWS  D ECEMBER 14,2013 NewD igesterFeedConveyor D ECEMBER 13,2013 RebuildingtheConstructionandD emolition (C&D )Building O CTO BER 8,2013 D igesterRamFeedSystemO verhaul AUGUST8,2013 NewProcessingEquipment SERVICES H ISTO RY AW ARD S NEW S&U PD ATES RECYCLING TIPS CO NTACTU S Page 9 of 12Waste Options, Inc. | Nantucket’s solid waste management and recycling facility 9/5/2014http://wasteoptions.com/ RECYCLING TIPS W hyRecycle?Becausetheprocessofconvertingusedwaste andmaterialsinto newproductshelpsuskeep Nantucketgreen.W earealso abletominimizepollutionandsaveenergy. Manydifferentmaterialscanberecycledincluding glass, metal,paper, textiles,andcomputer equipment. WEHAVETHEHIGHEST RECYCLERATEINAMERICA SERVICES H ISTO RY AW ARD S NEW S&U PD ATES RECYCLING TIPS CO NTACTU S Page 10 of 12Waste Options, Inc. | Nantucket’s solid waste management and recycling facility 9/5/2014http://wasteoptions.com/ CONTACT US.Come and say hello to our team. Name EmailAddress StreetAddress City State ZIP   WE'REHEREFORYOU. Feelfreeto reach out andcontact usatany time. WHEREAREWE? WasteOptions 50 OliverStreet Suite215 N.Easton,MA02356 P -508-238-4044 F -508-238-4144 188 Madaket Road Nantucket,Massachusetts 02554 SERVICES HISTORY AWARDS NEWS&UPDATES RECYCLING TIPS CONTACTUS Page 11 of 12Waste Options, Inc. | Nantucket’s solid waste management and recycling facility 9/5/2014http://wasteoptions.com/ SERVICES HISTORY AWARDS NEWS&UPDATES RECYCLING TIPS CONTACTUS Page 12 of 12Waste Options, Inc. | Nantucket’s solid waste management and recycling facility 9/5/2014http://wasteoptions.com/ A. B. T own ofN ant ucke t , M A Frid ay, Se pt e m be r 5, 2014 Ch ap ter 125. SO L I D W ASTED I SP O SAL [H I S T O RY:Ad opted by th e T ow n Meeting ofth e T ow n ofNantucketasind icated in article h istories. T h isch apter w asform erly includ ed in th e Cod e asCh .9 1, butw asrenum bered 4- 15- 2003AT M by Art. 26, approved 8 - 27- 2003.Am end m entsnoted w h ere applicable.] GEN ERAL REFEREN CES S olid w aste enterprise — S ee Ch .42. ArticleI . G eneralP ro v isio ns [Ad opted 4- 10- 19 8 9 AT M by Art.49 , approved 7- 24- 19 8 9 ] § 125- 1. So lid w asterulesand reg ulatio ns;land filluser fees. T h e Board ofS electm en ish ereby em pow ered to establish th e necessary rules, reg ulationsand fees for h and ling , processing and d isposalofth e T ow n'ssolid w aste.S uch feesare to be cred ited to th e g eneralfund ofth e T ow n ofNantucketand h eld and expend ed in accord ance w ith th e GeneralLaw s ofth e com m onw ealth . § 125- 2. Mand ato ry seg reg atio n and recy cling . [Am end ed 4- 8 - 19 9 6 AT M by Art.49 , approved 7- 24- 19 9 6] T h e Board ofS electm en, acting asth e Board ofPublic W orks, ish ereby required to instructth e d epartm entresponsible for solid w aste d isposalto establish , prom ulg ate and enforce reg ulationsto th e extentperm itted by th e GeneralLaw softh e com m onw ealth concerning th e follow ing m atters: T h e Departm entsh allestablish , prom ulg ate and enforce reg ulationsfor recy cling .T h e prog ram sh allinclud e butnotbe lim ited to, new spapers, card board , oth er paper articlesand m ag azines; clear, g reen and brow n g lass;alum inum and tin, includ ing cans;allnum bered plasticsand sty rofoam ;g rasscutting s, leaves, brush and lim bs;m etalappliances;tires;recy clable construction d ebris;and allm aterialslisted ash azard ousw aste by th e Massach usetts Departm entofEnvironm entalProtection.T h e rulesand reg ulationssh allprovid e penaltiesand fines. Restrictionsupon th e sale or d istribution ofcertain m aterialsd eem ed to be d etrim entalto th e NantucketMunicipalLand fill, com posting facility or th e island 'senvironm entin g eneral. § 125- 3. Bio d eg rad ablep ack ag ing . [Am end ed 12- 12- 19 8 9 S T M by Art.2, approved 3- 14- 19 9 0] Page 1 of 3Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471179&children=true A. B. Allpackag ing ad d ed to or supplied by vend orsor com m ercialestablish m entsw ith in th e T ow n of Nantucketfor m erch and ise ofany ty pe being rem oved from th e establish m entsh allcom ply w ith such rulesand reg ulationsrequiring th e use ofbiod eg rad able packag ing to th e m axim um extentreasonably practicable asm ig h tbe establish ed by th e Board ofPublic W orksafter a public h earing ;provid ed , h ow ever, th atth issection sh alltake effectApril15, 19 9 0."Biod eg rad able packag ing "m eansany packag ing oth er th an plastic or sty rofoam . § 125- 4. Transp o rto fso lid w asteto d isp o salfacility . Allload sofsolid w aste th atare und erg oing transportto th e T ow n'ssolid w aste d isposalsite for d isposalsh allbe fully covered in such a m anner asto preventstrew ing litter along th e road d uring transportation.T h e d isposalm aterialsm ustbe in a tied bag , covered container or oth erw ise fully covered , such asby a properly secured tarpaulin. § 125- 5. Seg reg atio n o fso lid w aste. Allpersonsentering th e T ow n ofNantucketsolid w aste d isposalfacility for th e purpose ofd isposalof solid w aste sh allbe responsible for th e seg reg ation ofsuch solid w aste into separate categ oriesfor separate d isposalor recy cling , asfollow s:g lass, rig id plastics, alum inum cansand ferrousm etalcans or ad d itionalcateg oriesasm ay be m ore fully d efined from tim e to tim e by reg ulationsofth e Board ofPublic W orksor itsd esig nee. § 125- 6. V io latio nsand p enalties. Allpersonsviolating any section ofth isarticle sh allbe subjectto th e penaltiessetforth in Ch apter 1 ofth e Cod e ofth e T ow n ofNantucket. ArticleI I . Unlaw fulD isp o salo fG arbag e [Ad opted 5- 5- 19 9 2AT M by Art.70, approved 8 - 3- 19 9 2] § 125- 7 . Trash barrelsand co ntainers;restricted use. I tsh allbe unlaw fulfor any person to d ispose ofh ouseh old or com m ercialg arbag e or refuse by placing itin or causing itto be placed in a trash barrelor oth er container w h ich h asbeen set upon a public street, sid ew alkor bicy cle path or upon oth er public property by th e T ow n for th e convenience ofth e traveling public. I tsh allbe unlaw fulfor any person to d ispose ofh ouseh old or com m ercialg arbag e or refuse by placing itin or causing itto be placed in a trash barrelor oth er container w h ich h asbeen law fully setupon private property by any ow ner or occupantofth e property for th e exclusive use ofsaid ow ner or occupantor h isor h er visitorsor patrons, w ith outth e auth orization ofsaid ow ner or occupant. Page 2 of 3Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471179&children=true A. B. § 125- 8 . V io latio nsand p enalties. Any police officer ofth e T ow n, th e S uperintend entofPublic W orksor h isd esig nee m ay utilize th e noncrim inald isposition specified in MGLc.40, § 21D. A violation ofth isarticle sh allbe punish able by a fine of$200. Page 3 of 3Town of Nantucket, MA 9/5/2014http://ecode360.com/print/NA0948?guid=11471179&children=true This copy is for your personal, noncommercial use only. You can order presentation-ready copies for distribution to your colleagues, clients or customers, please click here or use the "Reprints" tool that appears next to anyarticle. Visit www.nytreprints.com for samples and additional information.Order a reprint of this article now. » August 20, 1998 Nantucket: What a Dump By KIMBERLY STEVENS NANTUCKET, Mass.—THE early morning August sun beat down on Mary Langdon, 86, a manager of estate sales, as she stooped to pick two yellowing botanical prints in cherry wood frames from the ground. She blew the dust off. ''We all agree,'' Mrs. Langdon said with a dry smile. ''The only difference between us and the sea gulls is they have wings.'' Not that they get to everything first, though. Nantucket island -- off the coast of Massachusetts, harbor to generations of 19th-century whaling captains and haven to 20th-century summer residents, rich with stretches of unspoiled beach and rotten with wooden sailboats and shingled cottages weathered the gray of a widow's hair -- has a local scene that does not show up on postcards. A popular decorating and renovation resource, islanders call it the Madaket Mall. What it is is the dump. Inaugurated in 1988, the 17,500-square-foot Nantucket Citizens Recycling Drop- Off Center and Landfill -- complete with gray shingled shed -- has its own weekly social set, from year- round local residents to summer people. The Mercedeses pull in next to the trucks. ''The only thing that's missing is the coffee and doughnuts,'' said Mrs. Langdon, who has summered on Nantucket for 40 years. But oh, the things you'll find. Open from 7 A.M. until 3 P.M. on weekdays and 7 A.M. until noon on weekends, the dump, regulars agree, offers the best ''diving'' on Sunday, when what did not sell at Saturday tag sales gets, well, dumped. Spring and fall are good, when the season-rental storms of heavy cleaning wash up on Madaket's shores. In addition to a thick, down-easter flotsam of chintz chairs, wicker settees, architectural salvage, antique trunks, monogrammed Brooks Brothers shirts and late-model mountain bikes, there is real treasure. Last summer, Mrs. Langdon found an Empire sofa, circa 1850, in mint condition. ''Mind you, this never hit the ground,'' she said later that afternoon at home, gesturing with a willowy tanned arm toward the prize peach-upholstered sofa. ''It went from one man's truck right into the back of mine.'' Jeff Willett, director of public works, said, ''I don't think anyone has found the missing Rembrandts out there, but some valuable antiques have surfaced.'' Ole Lokensgard, 52, an architect who visits the dump twice a week, has done devotees like Mrs. Langdon one better. Page 1 of 2Nantucket: What a Dump -The New York Times 9/5/2014http://www.nytimes.com/1998/08/20/garden/nantucket-what-a-dump.html?pagewanted=print It is not the ornate clock, found there two years ago, signed ''E. Ingraham Co., Bristol, CT,'' that now graces his mantel. It is Mr. Lokensgard's house, which was largely built and furnished with dump items found and then incorporated into his design: from the cottage's oddly shaped windows to its mismatched doors, from the icebox hardware on the kitchen cabinets to the refuse lattice that encloses an outdoor shower. Each brick in the fireplace, which took Mr. Lokensgard three months to build, was handpicked. His wife, Mary, painted the family's eight dining chairs -- from multiple dives -- a sea-foam green, to make a set. Mr. Lokensgard pointed wistfully at a window that was a tad smaller than the one next to it. ''It's a mixed blessing with found stuff,'' he said. ''I refer to my house as the idiot savant house because of its eccentric nature.'' Last Saturday, as regulars took their positions by the drive-in entrance, the chatter was about the new one -year-old Nantucket Golf Club (with an initiation fee of $300,000), the horror of Kathy Lee Gifford buying a house on the island and a bald eagle that had taken up residence in the back section of the landfill. No one seemed to be paying attention to the sign in the corner of the discard shed: NO LOITERING , 15 MINUTES . The rule is not enforced. There are simple rules of etiquette at the dump that most seem to follow. If you pick something up, it is yours until you put it down. And so it goes. Regulars are quick to say the glory days may be ending. Stories of entire trunks filled with antique books, old photographs and estate jewelry are already folklore. With the island's new construction boom, the demolition of old homes and the influx of people with decorators on the payroll, the drop-offs have been good but the diving has become more competitive. And tidy innovations like recycling and the somewhat controversial ''take it or leave it'' pile have made it easier -- and more attractive -- for amateurs. Mr. Lokensgard, a former divinity student, is philosophical. ''If you are using the dump regularly, you become part of the community, and that means a lot to people,'' he said. He recalled dropping off an old boat chair. ''Gosh, I was hoping for one of these all morning,'' the man next to him exclaimed. Photos: PRO DIVING -- Mary Langdon, top, finds a framed botanical. Above, a wing chair arrives, and the ''gulls'' move in. Center, the ''take it or leave it'' shed. HOUSE OF DISCARDS -- Ole Lokensgard, above, with his daughter, Sonja, in the cottage he designed and furnished with dump materials, including ceiling and cabinetry wood, dining table and chairs, and the carved wood and cast iron clock, left, signed, ''E. Ingraham Co., Bristol, CT.'' (Photographs by Ed Quinn for The New York Times) Copyright 2014 The New York Times Company Home Privacy Policy Search Corrections XML Help Contact Us Back to Top Page 2 of 2Nantucket: What a Dump -The New York Times 9/5/2014http://www.nytimes.com/1998/08/20/garden/nantucket-what-a-dump.html?pagewanted=print Nantucket, MA (project #225139)Woodard & Curran CWMP Update September 2014 APPENDIX D: WANNACOMET WATER DATA It is being delivered to all customers, the Nantucket Board of Health, the Massachusetts Department of Public Health (DPH), and the Massachusetts Department of Environmental Protection (DEP). We strive to provide high quality drinking water that exceeds all Federal and Commonwealth drinking water standards, provide the highest level of customer and water related support services achievable, educate and inform the public of the need to protect Nantucket’s water resources, and to accomplish this using prudent utility practices and responsible fiscal manage- ment. As your water provider, we are carefully monitoring your water quality, improving our aging infrastructure and expanding service areas to make sure water is safe and available 24/7. Congress passed the Safe Drinking Water Act (SDWA) in 1974 to protect public health by regulating the nation’s public drinking water supply and protecting sources of drinking water. A public water system (PWS) is defined as one that serves piped water to at least 25 persons or 15 service connections for at least 60 days each year. SDWA is administered by the U. S. Environmental Protection Agency (EPA) and its state partners. The SDWA requires public notification of water systems violations, other notices and annual reports (Consumer Confidence Reports) to customers on contaminants found in their drinking water – www.eap.gov/safewater/ccr. This report is mandated by the federal government and presents many topics of interest along with the results of our 2012 Water Quality Data completed from January 1, 2012 through December 31, 2012 and summarizes the past year’s activities at Wannacomet Water Company. It is intended to inform the public about the quality of the water and the effort made by us to maintain it. We are commit- ted to ensuring the quality of your water and strive to adopt new and better meth- ods for delivering drinking water to you. Please take a moment to read this report as there is a great deal of information enclosed. Your Water System - where the water comes from... Wannacomet’s water is a groundwater supply. Water is pumped from three different groundwater wells located in Nantucket’s Sole Source Aquifer (geologic formations containing water). Our customers receive their drinking water from two different levels of the aquifer. The wells are located throughout the mid-island. The water is distributed through a network of water mains ranging in size from 2 inches to 16 inches in diameter. We depend on rainfall to recharge our water supply. The annual recharge to the aquifer from an average of 43 inches of precipitation more than makes up for the amount of water pumped from all sources. We are pleased to present the 2012 edition of our annual water quality report. Our constant goal is to provide you with a safe and dependable supply of drinking water. Major water issues are presented at monthly water commission meetings. The public is invited to participate in and voice its concerns about our drinking water. For meeting dates and location visit www.nantucket-ma.gov. Wannacomet Water Company during 2012 produced and delivered 612,314,000 gallons of drinking water from all of its wells. Our highest pumpage day in 2012 was 4,327,732 gallons on July 6, 2012. Total measured rainfall reported on Nantucket for the year 2012 was 32 inches, about 10 inches less than average. We installed 54 new service connections, 24 new fire hydrants and 10,806 feet of new water mains into the system by private developers and Wannacomet Water. Water Demand & Statistics Turn off the tap while brushing your teeth or shaving: save 1-2 gallons per minute. That trickling sound you hear in the bathroom could be a leaky toilet wasting 50 gallons of water a day or more. But sometimes it leaks silently. Try this: Crush a dye tablet in its envelope and carefully empty the contents into the center of the toilet tank and allow it to dissolve. Wait about 10 minutes. Inspect the toilet bowl for signs of blue dye indicating a leak. If the dye has appeared in the bowl, your flapper or flush valve may need to be replaced. Parts are inexpensive and fairly easy to replace. If no dye has appeared in 10 minutes time, you probably don’t have a leak. REMINDER: Emergency on-call person – 7 days a week – 24 hours a day. We have an emergency on-call utility person available during non-business hours, weekends and holidays. In the event of an emergency during non-business hours please con- tact us through the Nantucket Police Department at 508-228-1212. Wasted water can add up quickly. We take our water supplies for granted, yet they are limited. The average American uses about 90 gallons of water each day in the home. By using water wisely, we can save money and help the environment. More efficient water use can reduce the impact on the water supply and on your wallet: Water Conservation 2 What is SWAP? The Source Water Assessment and Protection (SWAP) program, established under the federal Safe Drinking Water Act, requires every state to: • inventory land uses within the recharge areas of all public water supply sources; • assess the susceptibility of drinking water sources to contamination from these land uses; and • publicize the results to provide support for improved protection. Source Water Assessment and Protection (SWAP) Report The SWAP report was compiled by the Massachusetts Department of Environmental Protection with assistance from the Wannacomet Water Company staff to inventory land uses within the Wellhead Protection District (WPD) and assess their potential to negatively impact the aquifer. Wannacomet Water Company’s complete SWAP report can be viewed at: http://www.mass.gov/dep/water/ drinking/4197000.pdf 3 Contaminants in Bottled Water and Tap Water Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contami- nants. The presence of contaminants does not necessarily indicate that the water poses a health risk. More information about contaminants and potential health effects can be obtained from the Environmental Protection Agency’s Safe Drinking Water Hotline (800-426-4791). In order to ensure that tap water is safe to drink, Massachusetts DEP and the EPA prescribe regulations which limit the amount of certain contaminants in water provided by public water systems. Food and Drug Administration (FDA) and the Massachusetts Department of Public Health regulations estab- lish limits for contaminants in bottled water that must provide the same protection for public health. Contaminants General sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up sub- stances resulting from animal or human activity. Contaminants that may be present in source water include: • Microbial contaminants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife; • Radioactive contaminants, which can be naturally occurring or the result of oil and gas production and mining activities; • Pesticides and herbicides, which may come from a variety of sources such as agriculture, urban storm water run off, and residential uses; • Inorganic contaminants, such as salts and metals, which can be naturally occurring or result from urban storm water run off, industrial or domestic waste water discharges, oil and gas production, mining, or farming; • Organic chemical contaminants, including synthetic and volatile organic chemicals, which are by-products of industrial processes and petroleum production, and can also come from gas stations, urban storm water run off and septic systems. Special Health Information Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompro- mised persons such as persons undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk of infection. These people should seek advice about drinking water from their health care providers. Environmental Protection Agency (EPA) and Centers for Disease Control and Prevention (CDC) guidelines on appro- priate means to lessen the risk of infection by cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline (800-426-4791). What the EPA Says About Drinking Water Contaminants Important Contacts Massachusetts Department of Environmental Protectionwww.state.ma.us/dep (617) 292-5500 Massachusetts Department of Public Healthwww.state.ma.us/dph (617) 624-6000 Town of Nantucketwww.nantucket-ma.gov US Centers for Disease Control & Prevention www.cdc.gov (800) 232-4636 Environmental Protection Agency www.epa.gov (800) 426-4791 List of Certified Water Quality Testing Labswww.mwra.com (617) 242-5323 Wannacomet Water Company www.wannacomet.org for our staff directory (508) 228-0022 The U.S. EPA Office of Water (www.epa.gov/watrhome) and the Centers for Disease Control and Prevention (www.cdc.gov) web- sites provide a substantial amount of information on many issues relating to water resources, water conservation and public health. Also, the Massachusetts Department of Environmental Protection has a website (www.state.ma.us/dep) that provides complete and current information on water issues in our state. Our Public Water Supply (PWS) ID # MA 4197000 Member: American Water Works Association (AWWA),New England Water Works Association (NEWWA),Barnstable County Water Utility Association (BCWUA),Massachusetts Water Works Association (MWWA),The Groundwater Foundation Retirement Customer Service Supervisor Jan Davis retired on July 1, 2012 after thirty-four years of service to Wannacomet Water Company. We value her friendship and wish her the very best in her future endeavors. Staff News – Service Awards On December 12, 2012 at the Public Safety Facility Community Room the Board of Selectmen recognized and presented a service award pin to Andrea Mansfield recognizing her ten years of service. Nantucket Island Chamber of Commerce Wannacomet Water Company general manager Bob Gardner was elected in October, 2012 as the President of the Nantucket Island Chamber of Commerce. Public Outreach In 2012 Wannacomet Water Company partnered with the Maria Mitchell Association and Sustainable Nantucket. We look forward to working with these agencies to communicate our message about the value of Nantucket’s tap water and the need to invest in water infrastructure to our customers, seasonal visitors and media. Water Commission Commissioner Slavitz was voted chairman of the commission effective April 12, 2012. Wannacomet Water Historical Preservation Project Wannacomet Water Company has an extensive collection of historical documents and photographs tracing the evolution of the Wannacomet Water Company. A complete searchable historical documents index was completed in 2012. A History of Wannacomet Water Company – Moses Tapped the Washing Pond The Nantucket Water Commission is pleased to announce the publication of Moses Tapped the Washing Pond - A History of Wannacomet Water Company by Frances Ruley Karttunen. Copies are available for sale locally at Bookworks and Mitchell’s Book Corner. Nantucket Community Sailing For the fourth year Wannacomet Water Company provided sponsorship, water stations and reusable water bottles to Nantucket Community Sailing for the 2012 Nantucket Race Week during the Annual Opera House Cup. The stations allowed participants and spectators to fill their reusable water bottles with local tap water from Wannacomet Water Company. These stations removed the equivalent of 4,000 one time use plastic bottles from Nantucket’s waste stream. Nantucket Arts Council Wannacomet Water Company was proud to host and be the site for the 2012 Nantucket Arts Council Giant Magic Daffodil Garden. 4 Office Update This year’s report is dedicated to Jan Davis who retired on July 1, 2012 after 34 years of service. Andrea Mansfield and Bob Gardner 5 Office Update Sign up for e-bills Electronic bills are available. For information and to enroll for paperless statements contact us at ebill@wannacomet.org. On-Line Bill Payment with Unipay Gold Wannacomet accepts payments on-line using Unipay Gold. Customers can securely pay their bills either using their credit card (Mastercard and Discover) or bank account. Visit on the web at www.wannacomet.org. (please note: beginning January 1, 2013 there is a $0.25 processing fee assessed by Unipay Gold for all electronic check payments.) Auto Draft Bill Pay Wannacomet Water Company offers automatic bill pay at no cost to you. You may set up bill pay through your checking account or we can set you up as an auto draft customer. Auto draft customers receive bills by mail and/or by e-mail. Two weeks after the bills are issued on/or about the 15th of each month your balance due will be drafted as an ACH (Automated Clearing House) fund transfer from the designated bank account you authorize us to debit the amount due from. Sign up at www.wannacomet.org. Sewer Rates The Board of Selectmen acting as the Board of Sewer Commis- sioners review sewer rates on an annual basis. The Board voted on January 18, 2012 to increase seasonal rates (May 1 through October 31) to $8.00/ccf and off-season rates (November 1 through April 30) to $6.00/ccf. Rate payers should routinely check the town’s website (www.nantucket-ma.gov) and search budget information for the latest in proposed sewer rate increases and current project proposals under consideration by the town. A Civic Salute to Town of Nantucket Volunteers On April 23, 2012 the Nantucket Civic League recognized and thanked over 250 citizen volunteers for their service on elected and appointed Boards, Committees and Commissions. Commissioners Reinhard, Slavitz and Eldridge were honored for their service to the Wannacomet Water Company. Distribution System Wannacomet continues to strengthen its distribution system by installing new water meter mains to improve fire flows and circulation patterns. Upgrades have been undertaken and com- pleted for water mains, services, gate valves and fire hydrants. Siasconset Water Department The management agreement between Siasconset Water Department and the Wannacomet Water Company continued in 2012. We continue to provide certified operators, technical, and administrative support to the Siasconset Water Department. Meter Upgrade Project The Flexnet meter replacement program continued in 2012. Upon completion in late 2013 all water meters will be read from our main office at 1 Milestone Road. The system will have the ability to track the water use patterns of individual accounts for a defined period of time. Washing Pond Tank Maintenance The Washing Pond Tank was recoated in 2012 by Rockwood Corporation. The project entailed replacing the external access ladder with a stainless steel ladder and safety climb system, redesigning the mounting system for communications equipment on the top of the standpipe, a new cable tray and complete internal and external recoating. Distribution System Continued Expansion to Madaket Phase III of the Madaket Road Water Main Extension was completed in 2012. Water Rates Effective 7/1/12 the water rate remained unchanged at $3.50 per 100 cubic feet. Visit our website at www.wannacomet.org for current rates and important notices. We urge you to visit our website at www.wannacomet.org. The updated site has many customer service forms and tips for water efficiency. There is also an on-line water use calculator. The calculator is effective in determining our water use patterns. We encourage you to check it out and see how much water you use on a daily basis. You can re-fill your own water bottles at Wannacomet! If you don’t have access to the town water supply at home, you can bring containers to Wannacomet Water Company at 1 Milestone Rd and fill up right outside the building. (fifty cents per gallon) 6 The last time lead and copper samples were collected from our system was in September, 2010. Based upon the excellent results of lead and copper sampling from 2008-2010 the Wannacomet Water Company was placed by the Massachusetts DEP on a reduced sampling schedule for lead and copper. The next scheduled sampling for lead and copper will take place in 2014. The Wannacomet Water Company is taking steps to further reduce the amount of lead in contact with drinking water by only installing water service materials that have been certified as being “no-lead”. What you need to know about lead in your tap water Water Quality Testing Results 2012 Inorganic Contaminants Nitrate 0.48 to 0.74 ppm 10 10 Runoff from fertilizer use, leaching from septic systems & erosion of natural deposits Fluoride 0 mg/l 4 4 Leaching from fertilizers and erosion of natural deposits Mercury 0 mg/l 0 0.002 Metal processing, coal incineration medical waste & atmospheric deposition Arsenic 0 mg/l 0 0.05 Erosion of natural deposits & runoff from orchards Cadmium 0 mg/l 0.005 0.005 Erosion of natural deposits & corrosion of galvanized pipe Level Detected Unit of Measurement MCLG MCL Possible Source of Contamination Microbiological Contaminates Total Coliform 1 presence or 0 presence of Naturally present in environment - Coliform bacteria Bacteria absence coliform in 5% are used as an indicator to the presence of other of monthly potentially harmful bacteria. samples SMCL = secondary maximum contaminant level. These standards are developed to protect the aesthetic qualities of drinking water and are not health based. ORSG = Massachusetts Office of Research and Standards guideline. This is the concentration of a chemical in drinking water, at or below which, adverse health effects are unlikely to occur after chronic (lifetime) exposure. If exceeded, it serves as an indicator of the potential need for further action. Radioactive Contaminants Gross Alpha 0 pCi/l 0 15 Erosion of natural deposits Radium 226 0 pCi/l 0 5 Decay of natural deposits & some man made deposits Radium 228 0 pCi/l 0 5 Decay of natural deposits & some man made deposits Volatile Organic Compounds Wannacomet Water Company sampled for 56 VOC contaminants and none were detected in the source water. One violation resolved by re-sampling at location and up and down stream locations The follow-up sample and the up and down stream locations showed no coliform present Public Notice for Coliform Violation – We routinely monitor for drinking water contaminants. We took 26 samples to test for the presence of coliform bacteria on September 10, 2012. Three (3) of our samples showed the presence of total coliform bacteria. The standard is that no more than (1) may do so. Follow-up samples were taken at the locations as well as an additional sample upstream and downstream at these locations. The follow-up samples and the upstream and downstream samples indicated no presence of coliform bacteria. All of the three locations were included in routine sampling done on September 20, 2012 and all sample results were coliform absent and this testing showed the problem to be resolved. This notice was published in The Inquirer and Mirror on October 4, 2012. For more information, please contact Robert Gardner or Mark Willett at 508-228-0022. Wannacomet Water Company has prepared this annual drinking water Consumer Confidence Report (CCR) to provide you with information regarding your drinking water. This report includes detected contaminants found in your drinking water, compliance issues related to the water quality, operational matters, and general education information regarding the condition of your drinking water. Share this report: Landlords, businesses, schools, hospitals, and other groups are encouraged to share this important water quality information with water users at their location. For water or meter problems, leaks, fire hydrants, water billing, and miscellaneous questions – call Wannacomet Water at 508-228-0022. For comments and suggestions, please email us at info@wannacomet.org. Our Annual Water Quality Report If you need a large print version of this Annual Water Quality report, please contact us at 508-228-0022 7 (PWS) ID #MA4197000 Robert L. Gardner General Manager Nelson K. Eldridge Commissioner Noreen Slavitz Commissioner Allen Reinhard Commissioner Photo (from left to right):Nelson Eldridge, Nonie Slavitz, Bob Gardner and Allen Reinhard Nantucket Water Commission Nelson K. Eldridge, Commissioner Noreen “Nonie” Slavitz, Chairman Allen Reinhard, Commissioner________________________________ General Manager, Robert L. Gardner Operations Manager, Christopher R. Pykosz Business Manager, Heidi Holdgate Maximum Contaminant Level Goal (MCLG): The “Goal” is the level of a contaminant in drinking water below which there is no known or expected risk to healthy persons. MCLGs allow for a margin of safety. Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs is feasible using the best available treatment technology. CDC = Centers for Disease Control and Prevention ND: Not detected. Laboratory analysis indicated that the constituent is not present. Variances and Exemptions: State or EPA permis- sion not to meet an MCL or a treatment technique under certain conditions. The data presented in this report is from the most recent testing done in accordance with regulations. Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drink- ing water. Action Level (AL): The concentration of a contaminant, which, if exceeded, triggers a treatment or other requirements that a water system must follow. Parts Per Million (ppm): one part per million corresponds to one minute in two years or a single penny in $10,000. Parts Per Billion (ppb): one part per billion corresponds to one minute in 2,000 years, or a single penny in $10,000,000. PCI/L: picoCuries per liter (a measure of radiation) DEP = Department of Environmental Protections EPA = Environmental Protection Agency NA: Not applicable. Important Definitions REMINDER:Emergency on-call person – 7 days a week – 24 hours a day. We have an emergency on-call utility person available during non-business hours, weekends and holidays. In the event of an emergency during non-business hours please contact us through the Nantucket Police Department at 508-228-1212. Meeting the Challenge We are once again proud to present our annual water quality report. Over the years, we have dedicated ourselves to providing drinking water that meets all state and federal drinking water standards. As your water provider, we are constantly monitoring your water to make sure that it’s safe and available 24/7. This report presents our 2009 Water Quality Data compiled from January 1, 2009 through December 31, 2009 and summarizes the past year’s activities at Wannacomet Water Company. The Safe Drinking Water Act (SDWA) requires that utilities issue an annual “Consumer Confidence” report to customers. It is intended to inform the public about the quality of the water and the effort made by us to maintain it. We are committed to ensuring the quality of your water and strive to adopt new and better methods for delivering drinking water to you. This publication is mandated by the federal government to provide water quality information to consumers. Please take a moment to read this report as there is a great deal of information enclosed. The new water tank will have a capacity of two million gallons, with all of it considered “usable” and will be painted slate gray. The construction of both the North Pasture and the Siasconset tanks will provide a significant boost for the Nantucket economy. The project manager for Chicago Bridge & Iron has stated that they expect to inject $1,600,000 into the local economy by utilizing local contractors and purchas- ing goods and services whenever possible. At calendar year-end 2009 we estimate over three dozen local businesses ben- efited from these two projects. Investing In Our FutureOn the horizon… Construction is underway and the North Pasture water tank is expected to be completed in July, 2010. 2 Where does Wannacomet’s Water come from? Wannacomet’s water is a groundwater supply. Water is pumped from three different groundwater wells located in Nantucket’s Sole Source Aquifer – the only source of drinking water on Nantucket. Our customers receive their drinking water from two different levels of the aquifer. The wells are located throughout the mid-island. The water is distributed through a network of water mains ranging in size from 2 inches to 16 inches in diameter. We depend on rainfall to recharge our water supply, which we draw from the groundwater. The annual recharge to the aquifer from an average of 43 inches of precipitation more than makes up for the amount of water pumped from all sources. Wannacomet celebrated National Drinking Water Week May 3-9, 2009. A safe, reliable water supply is critical to the success of any community. It creates jobs, attracts industry and investment, and provides for the health and welfare of citizens in ways ranging from disease prevention to fire suppression. We often take water supply for granted until it is threatened, either by drought, water main breaks, or some other event. For more than 30 years, the American Water Works Association and its members have celebrated Drinking Water Week – a unique opportunity for both water professionals and the communities they serve to join together to recognize the vital role water plays in our daily lives. The Wannacomet Water Company is committed to providing educational water-related programs and resources to the community. Opera House Race Week - Wannacomet assisted with the Opera House Race organizers with a water system to help reduce the number of water bottles used during the event. It was estimated that 4500 plastic water bottles were saved. Major water issues are presented at monthly water commission meetings. The public is invited to participate in and voice concerns about our drinking water. Meetings are at 8:00am on the second Thursday of every month. Educational and Community NewsShould I buy bottled water? Water Use Calculator We urge you to visit our website at www.wannacomet.org. We have on-line a water use calculator for our customers. The calculator is effective in determining your water use patterns. We encourage you to check it out and see how much water you use on a daily basis. Water used for irrigation and landscaping should be used in accordance with the recommendations of professional landscapers and irrigation specialists. You don’t need to buy bottled water for health reasons if your drinking water meets all of the federal, state, or provincial drinking water standards. If you want a drink with a different taste, you can buy bottled water, but it costs up to 1,000 times more than municipal drinking water. Of course, in emergencies bottled water can be a vital source of drinking water for people without water. The US Food and Drug Administration (FDA) requires bottled water quality standards to be equal to those of the US Environmental Protection Agency for tap water, but the quality of the finished product is not gov- ernment-monitored. Bottlers must test their source water and finished product once a year. Currently, any bottled water that contains contaminants in excess of the allowable level is considered mislabeled unless it has a statement of substandard quality. Our Mission Statement The Wannacomet Water Company shall strive to provide high quality drinking water that exceeds all established Federal and Commonwealth drinking water standards, provide the highest level of customer and water related services achievable, educate and inform the public of the need to protect Nantucket’s water resources, and to accomplish this mission using prudent utility practices and responsible fiscal management. 3 Contaminants in Bottled Water and Tap Water Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that the water poses a health risk. More information about contaminants and potential health effects can be obtained from the Environmental Protection Agency’s Safe Drinking Water Hotline (800-426-4791). In order to ensure that tap water is safe to drink, Massachusetts DEP and the EPA prescribe regulations which limit the amount of certain contaminants in water provided by public water systems. Food and Drug Administration (FDA) and the Massachusetts Department of Public Health regulations establish limits for contaminants in bottled water that must provide the same protection for public health. Contaminants General sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from animal or human activity. Contaminants that may be present in source water include: • Microbial contaminants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife; • Inorganic contaminants, such as salts and metals, which can be naturally occurring or result from urban storm run off, industrial or domestic waste water discharges, oil and gas production, mining, or farming; • Pesticides and herbicides, which may come from a variety of sources such as agriculture, urban storm water run off, and residential uses; • Organic chemical contaminants, including synthetic and volatile organic chemicals, which are by-products of industrial processes and petroleum production, and can also come from gas stations, urban storm water run off and septic systems; • Radioactive contaminants, which can be naturally occurring or the result of oil and gas production and mining activities. Special Health Information Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons such as persons undergoing chemotherapy, persons who have under- gone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk of infection. These people should seek advice about drinking water from their health care providers. Environmental Protection Agency (EPA) and Centers for Disease Control and Prevention (CDC) guidelines on appropriate means to lessen the risk of infection by cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline (800-426-4791). What the EPA Says About Drinking Water ContaminantsJust a few reminders….wasting water can add up quickly. On average, each person uses about 65 gallons of water each day. Fix Leaks. Dripping, trickling, or leaking faucets, showerheads and toilets can waste up to several hundred gallons of water a week depending on the size of the leaks. That trickling sound you hear in the bathroom could be a leaky toilet, but some times toilets leak silently. One way to test your toilet is to drop a dye tablet in the toilet tank and allow it to dissolve. After about 20 minutes inspect the toilet bowl for signs of dye indicating a leak, if the dye has appeared in the bowl, your flapper or flush valve may need to be replaced. Parts are inexpensive and fairly easy to replace. Take shorter showers. Install a Low-Flow Showerhead and Faucet Aerator. Some showerheads may still use over 5 gallons per minute. A low-flow showerhead uses 2.5 gallons or less and can save you over 200 gallons per 10-minute shower. A low flow-aerator can reduce the flow by about 25%. Turn the faucet off while brushing teeth, washing your face, and/or shaving. Run dishwashers and washing machines only when full. Water your lawn (and other landscaping) in the early morning or evening to avoid evaporation. Visually inspect your sprinkler system once a month during daylight hours. Check and fix any tilted, clogged or broken heads. Water Conservation In 1974, the federal government established the Safe Drinking Water Act to protect the public from water-related illnesses. This law requires community water systems to regularly test their water supplies and meet strict federal water quality stan- dards. Many states have even more stringent requirements. Water providers conduct thou- sands of analyses each year to verify that the public water supply meets these standards, and the Safe Drinking Water Act requires they provide an- nual water quality reports to their customers. Contact us if you have not received a copy of your report. Did you know... Water Conservation Staff news – Utilityman Kyle Roberts passed the Massachusetts Board of Certification Water Treatment Operator’s Certification examination. Water Rates and Connection Fees – There was no increase in the water rate, basic charge or the water connection fee in 2009. As a reminder the basic charge for water service is set by the Nantucket Water Commission. Customers are billed this charge even though the water meter is turned off for the winter or if there is zero usage read on the meter. This charge covers our oper- ating expenses; such as debt, insurance costs, distribution system maintenance and billing and customer support services. Sewer Rate Increase – The Board of Selectmen acting as the Board of Sewer Commissioners voted to increase sewer user fees for fiscal year 2010 by adopting a seasonal de- mand model developed with the Abrahams Group and increasing the quarterly non-metered user fee. New rates were effective July 1, 2009. The model is reviewed monthly with quarterly reports presented to the Board of Selectmen. On-Line Bill Payment Option – Wannacomet accepts payments on-line using Unibank Financial Services. Customers can securely access and pay their bills either using their credit card (Mastercard and Discover) or checking account. Visit on the web at www.wannacomet.org. Electronic bills (paperless statements) are scheduled for late spring, 2010. Computer and Information Technology – In 2009 we completed the main office computer network systems upgrade. Wannacomet’s information systems and infrastructure are supported by the Town of Nantucket’s IT department. Siasconset Water Department– In 2009 the Nantucket Water Commission and the Siasconset Water Commis- sion renewed their Memorandum of Agreement whereby Wanna- comet Water Company provides certified operators and technical and administrative support to the Siasconset Water Department. This agreement is reviewed on an annual basis. The new water tank in Siasconset is under construction with an estimated completion date of September, 2010. Retirement – David D. Worth concluded his service to the Nantucket Water Commission when his term ended in April, 2009. David’s service to the Wannacomet Water Company as General Manager and Commissioner spanned 39 years of dedicated service. New Commissioner – Allen Reinhard was elected in April, 2009 to his first term as Water Commissioner. We welcome Allen and look forward to his service to Wannacomet. A.W.W.A. Public Officials Certification – Commissioner Nonie Slavitz completed the American Water Works Public Officials Certification program at the A.W.W.A. Annual Conference in San Diego, CA. The program focuses specifically on water issues and provides elected and appointed public officials with ongoing professional development and a platform for network- ing opportunities with other policy leaders. It is designed to develop and enhance critical skills and abilities necessary to achieve excellence in organizations, and to enhance communication and sharing between public officials from diverse communities. Nonie is a strong advocate of continuing education for public officials and has been an active participant since inception of the program. Nonie Slavitz was also re-elected to the NWC and elected Chairperson effective 4/15/09. Commissioner Eldridge celebrates 50 years of service with the Nantucket Fire Department – Nelson Eldridge – celebrated 22 years of service as a water commissioner and 50 years of service to the Nantucket Fire Department. Customer Outreach – In 2009 Wanncomet continued its partnership with Plum TV to provide information about Nan- tucket’s water supply. Our goal is to build the public’s confidence in our drinking water. Plum TV is a valuable partner in communicating Wannacomet’s message about the value of Nantucket’s tap water and the need to invest in water infrastructure to our customers, seasonal visitors, media and other key stakeholders. Neighborhood Improvement – In 2009 Wannacomet continued to strengthen its distribution system by installing new water mains to improve fire flows and circulation patterns (some of the mains were installed in the late 1880’s). Working in partnership with the Department of Public Works, new water mains (5,888 feet), services (106), gate valves and fire hydrants (12) were installed in those areas under construction in the core historic district specifically on Orange, Pine, Liberty and Easton streets for sewer and storm water improvements. This partnership resulted in substantial savings for Wannacomet. Town Water in the Works for Madaket – The water main extension project to Madaket continued during 2009. Engineering, design and permitting are complete. In April, 2009 Wannacomet announced the town’s intention to extend town water to Madaket for expedited firefighting and improved water quality, and simply because the costs for installing the main were so low during this recession that the Wannacomet could not afford to miss this opportunity. The bid process is scheduled for spring, 2010. 4 David D. Worth Office Update 5 Water Demand & Statistics Like many organizations Wannacomet Water Company is experi- encing the effects of the recent economic slowdown. New service connections continued to decline in 2009. Production is at all time lows and is reflective on the cool and wet weather of the past summer months. In 2009, the Wannacomet Water Company pumped 519,397 million gallons of drinking water from our wells. Our highest pumpage day in 2009 was 3,295,265 gallons on July 27, 2009. Total mea- sured rainfall reported for the year 2009 was 38 inches (Nantucket’s average rainfall is 43 inches per year). We in- stalled over 37 new service connections, 5 new fire hy- drants and 625 feet of new water mains were installed by private developers and individuals. We are required to monitor your drinking water for specific man- made and naturally occurring contaminants on a regular basis. Results of regular monitoring are an indicator of whether or not our drinking water meets with health standards. During the third quarter of 2009 (July – September) we did not monitor or test lead and copper and therefore cannot be sure of the quality of our drinking water during that time. We had received a revised sampling schedule from the Massachusetts D.E.P. that required sampling for lead and copper in the 3rd quarter of 2009. The previous schedule did not require this sampling. We inad- vertently referred to the old sched- ule for 3rd quarter sampling and did not take the lead and copper samples in the 3rd quarter. When we were made aware of this error we immediately took the required lead and copper samples. The results of those samples were received and did not indicate lead and copper levels above those allowed by the drinking water regulations for these contaminants. Thirty-three samples were taken 10/29/09-11/5/09 and should have been taken 7/1/09-9/30/09. What is SWAP? The Source Water Assessment and Protection (SWAP) program, established under the federal Safe Drinking Water Act, requires every state to: • inventory land uses within the recharge areas of all public water supply sources: • assess the susceptibility of drinking water sources to contamination from these land uses; and • publicize the results to provide support for improved protection Source Water Assessment (SWAP) Report The SWAP report was compiled by the Massachusetts Department of Environmental Protection with assis- tance from the Wannacomet Water Company staff to inventory land uses within the Wellhead Protection District (WPD) and assess their potential to negatively impact the aquifer. Wannacomet Water Company’s complete SWAP report can be viewed at: http://www.mass.gov/dep/water/ drinking/4197000.pdf Important Contacts Massachusetts Department of Environmental Protection (DEP) www.state.ma.us/dep (617) 292-5500 Massachusetts Department of Public Health (DPH) www.state.ma.us/dph (617) 624-6000 Town of Nantucket www.nantucket-ma.gov US Centers for Disease Control & Prevention (CDC) www.cdc.gov (800) 232-4636 Environmental Protection Agency (EPA) www.epa.gov (800) 426-4791 List of Certified Water Quality Testing Labs www.mwra.com (617) 242-5323 Wannacomet Water Company www.wannacomet.org for our staff directory The U.S. EPA Office of Water (www.epa.gov/watrhome) and the Centers for Disease Control and Prevention (www.cdc.gov) websites provide a substantial amount of information on many issues relating to water resources, water conservation and public health. Also, the Massachusetts Department of Environmental Protection has a website (www.state.ma.us/ dep) that provides complete and current information on water issues in our state. Our Public Water Supply (PWS) ID # MA 4197000 Member: American Water Works Association (AWWA), New England Water Works Association (NEWWA), Barnstable County Water Utility Association (BCWUA), Massachusetts Water Works Association (MWWA), The Groundwater Foundation Inorganic Contaminants Nitrate 0.59 ppm 10 10 Runoff from fertilizer use, leaching from septic systems & erosion of natural deposits Mercury 0 ppb 2 2 Leaching from municipal landfills and sewage, and metal refining If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. Wannacomet Water Company is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumb- ing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drink- ing or cooking. If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drink- ing water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline or at: http://www.epa.gov/safewater/lead Call the Department of Public Health at 1-800-532-9571 or EPA at 1-800-424-LEAD (5323) for health information. Lead can get into tap water through pipes in your home, your lead service line, lead solder used in plumbing, and some brass fixtures. Corrosion or wearing away of lead-based materials can add lead to tap water, especially if water sits for a long time in the pipes before it is used. Under EPA rules, each year Wannacomet must test tap water in a sample of homes that are likely to have high lead levels. These are usually homes with lead service lines or lead solder. The EPA rule requires that 9 out of 10, or 90%, of the sampled homes must have lead levels below the Action Level of 15 parts per billion (ppb). What you need to know about lead in Your Tap Water Water Quality Testing Results 2009 Level Detected 6 The last time lead samples were collected from our system was in September, 2009. The results are below: Range of Detection (mg/l) Action Level (mg/l) MCLG (mg/l) Lead & Copper (samples taken second quarter 2009) Lead 0.0 - 0.003 0 0.015 30 0.002 0 Corrosion of Plumbing Copper 0 - 0.66 1.3 1.3 30 0.12 0 Corrosion of Plumbing Unit of Measurement MCLG MCL Possible Source of Contamination Synthetic Organic Contaminants Microbiological Contaminates 2,4,5-TP (Silvex) 0 ppb 50 50 Runoff/leaching from herbicide and pesticide use Atrazine 0 ppb 3 3 Runoff/leaching from herbicide and pesticide use Simazine 0 ppb 4 4 Runoff/leaching from herbicide and pesticide use Total Coliform 0 presence or 0 presence of Naturally present in environment Coliform Bacteria absence coliform in 5% bacteria are used as an indicator to the presence of monthly of other potentially harmful bacteria. samples There were no total coliform violations for Wannacomet in 2009. # of Samples # of sites Exceeding Action Level Possible Source of Contamination 90% Percentile Value SMCL = secondary maximum contaminant level. These standards are developed to protect the aesthetic qualities of drinking water and are not health based. ORSG = Massachusetts Office of Research and Standards guideline. This is the concentration of a chemical in drinking water, at or below which, adverse health effects are unlikely to occur after chronic (lifetime) exposure. If exceeded, it serves as an indicator of the potential need for further action. Unregulated and Secondary Contaminants with State Standards (ORSGs and/or SMCLs) MTBE (ppb) Range Detected Average SMCL ORSG Possible Sources Methyl Tertiary ND 0 20-40 70 Fuel Additive Butyl Ether Volatile Organic Compounds Tetrachloroethylene 0 ppb 0 5 Leaching from vinyl lined pipes, dry-cleaning (PCE) operations & some degreasing agents. Benzene 0 ppb 0 5 Leaching from gas storage tanks & landfills Maximum Contaminant Level Goal (MCLG): The “Goal” is the level of a contaminant in drinking water below which there is no known or expected risk to healthy. MCLGs allow for a margin of safety. Maximum Contaminant Level (MCL): The highest level of a con- taminant that is allowed in drinking water. MCLs are set as close to the MCLGs is feasible using the best available treatment technology. Variances and Exemptions: State or EPA permission not to meet an MCL or a treatment technique under certain conditions. The data presented in this report is from the most recent testing done in accordance with regulations. Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water. ND: Not detected. Laboratory analysis indicated that the constituent is not present. Action Level (AL): The concentration of a contaminant, which, if exceeded, triggers a treatment or other requirements that a water system must follow. NA: Not applicable. Parts Per Million (ppm): one part per million corresponds to one minute in two years or a single penny in $10,000. Parts Per Billion (ppb): one part per billion corresponds to one minute in 2,000 years, or a single penny in $10,000,000. PCI/L - picoCuries per liter (a measure of radiation) EPA = Environmental Protection Agency DEP = Department of Environmental Protections CDC = Centers for Disease control and Prevention Wannacomet Water Company has prepared this annual drinking water Consumer Confidence Report (CCR) to provide you with information regarding your drinking water. This report includes detected contaminants found in your drinking water, compliance issues related to the water quality, operational matters, and general education information regarding the condition of your drinking water. Share this report: Landlords, businesses, schools, hospitals, and other groups are encouraged to share this important water quality information with water users at their location. For water or meter problems, leaks, fire hydrants, water billing, and miscellaneous questions – call Wannacomet Water at 508-228-0022. For comments and suggestions, please email us at info@wannacomet.org. Our Annual Water Quality Report Allen Reinhard, Nelson Eldridge, Nonie Slavitz and Bob Gardner If you need a large print version of this Annual Water Quality report, please contact us at 508-228-0022 7 Nantucket Water Commission Nelson K. Eldridge, Chairman Noreen “Nonie” Slavitz, Commissioner Allen Reinhard, Commissioner________________________________ General Manager, Robert L. Gardner Operations Manager, Christopher R. Pykosz Business Manager, Heidi HoldgateAllen ReinhardCommissioner (PWS) ID #MA4197000 Important Definitions August 2004 Source Water Assessment and Protection (SWAP) Report Page 1 Massachusetts Department of Environmental Protection Source Water Assessment and Protection (SWAP) Report for Wannacomet Water Company What is SWAP? The Source Water Assessment and Protection (SWAP) program, established under the federal Safe Drinking Water Act, requires every state to: ·inventory land uses within the recharge areas of all public water supply sources; ·assess the suscepti bility of drinking water sources to contamination from these land uses; and ·publicize the results to provide support for improved protection. Susceptibility and Water Quality Susceptibility is a measure of a water supply’s potential to become contaminated due to land uses and activities within its recharge area. A source’s susceptibility to contamination does not imply poor water quality. Water suppliers protect drinking water by monitoring for more than 100 chemicals, disinfecting, filtering, or treating water supplies, and using source protection measures to ensure that safe water is delivered to the tap. Actual water quality is best reflected by the results of regular water tests. To learn more about your water quality, refer to your water supplier’s annual C onsumer Confidence Reports. Introduction We are all concerned about the quality of the water we drink. Drinking water wells may be threatened by many potential contaminant sources, including storm runoff, road salting, and improper disposal of hazardous materials. Citizens and local officials can work together to better protect these drinking water sources. Purpose of this report This report is a planning tool to support local and state efforts to improve water supply protection. By identifying land uses within water supply protection areas that may be potential sources of contamination, the assessment helps focus protection efforts on appropriate Best Management Practices (BMPs) and drinking water source protection measures. Refer to Table 3 for Recommendations to address potential sources of contamination. Department of Environmental Protection (DEP) staff are available to provide information about funding and other resources that may be available to your community. This report includes the following sections. 1. Description of the Water System 2. Land Uses within Protection Areas 3.Source Water Protection Conclusions and Recommendations 4.Appendices Table 1: Public Water System Information PWS Name Wannacomet Water Company PWS Address 1 Milestone Road City/Town Nantucket, Massachusetts 02554 PWS ID Number 4197000 Local Contact Robert Gardner Phone Number (508) 228-0022 August 2004 Source Water Assessment and Protection (SWAP) Report Page 2 What is a Protection Area? A well’s water supply protection area is the land around the well where protection activities should be focused. Each well has a Zone I protective radius and a Zone II protection area. Glossary Aquifer: An underground water- bearing layer of permeable material that will yield water in a usable quantity to a well. Hydrogeologic Barrier: An underground layer of impermeable material (i.e. clay) that resists penetration by water. Recharge Area: The surface area that contributes water to a well. Zone I: The area closest to a well; a 100 to 400 foot radius proporti onal to the well’s pumping rate. This area should be owned or controlled by the water supplier and limited to water supply activities. Zone II: The primary recharge area for the aquifer. This area is defined by hydrogeologic studies that must be approved by DEP. Refer to the attached map to determine the land within your Zone II. Wannacomet Water Company pumps groundwater from three different groundwater wells located in Nantucket’s Sole Source Aquifer. All of the wells are located in one Zone II primary recharge area. The Milestone Well #2 and State Forest Well #3 have Zone I protection areas with a radius of 400 feet. The Milestone Well #1 has a Zone I protection area that extends 250 feet from the perimeter of the wellfield (each individual wellpoint). The wells are located in an aquifer with a high vulnerability to contamination due to the absence of hydrogeologic barriers (i.e. clay) that can prevent contaminant migration. Please refer to the attached map to view the boundaries of the Zone Is and Zone II. Presently, Wannacomet Water Company does not treat the water. For current information on monitoring results, please contact the Public Water System contact person listed above in Table 1 for a copy of the most recent Consumer Confidence Report. Drinking water monitoring reporting data are also available on the web at http://www.epa.gov/safewater/ccr1.html. Section 2: Land Uses in the Protection Areas The Zone II for Wannacomet Water Company is dominated by open space, forest and residential land uses with smaller areas of commercial and light industrial land uses (refer to attached map for details). Land uses and activities that are potential sources of contamination are listed in Table 2, with further detail provided in the Table of Regulated Facilities and Table of Underground Storage Tanks in Appendix A. Key Land Uses and Protection Issues include: 1. Zone Is; 2. residential land uses; 3. transportation corridors; 4. hazardous materials storage and use; 5. oil or hazardous material contamination sites; and 6. comprehensive wellhead protection planning. The overall ranking of susceptibility to contamination for the system is high, based on the presence of at least one high threat land use within the water supply protection areas, as seen in Table 2. 1. Zone Is – The Zone I for each of the wells is a 400 foot radius around the wellhead and the Zone I for the wellfield is 250 feet around the individual well points. Massachusetts drinking water regulations (310 CMR 22.00 Drinking Water) requires public water suppliers to own the Zone I, or control the Zone I through a conservation restriction. The three Zone Is for the wells are owned or controlled by the public water system. Only water supply activities are allowed in the Zone I. However, many public water supplies were developed prior to the Department's regulations and contain non water supply activities such as homes and public roads. The following activities of concern occur in the Zone Section 1: Description of the Water System Zone II #: 215 Susceptibility: High Well Names Source IDs Milestone Road Well #1 (Wellfield) 4197000-01G Milestone Road Well #2 4197000-02G State Forest Well #3 4197000-03G August 2004 Source Water Assessment and Protection (SWAP) Report Page 3 Benefits of Source Protection Source Protection helps protect public health and is also good for fiscal fitness: ·Protects drinking water quality at the source ·Reduces monitoring costs through the DEP Waiver Program ·Treatment can be reduced or avoided entirely, saving treatment costs ·Prevents costly contamination clean-up ·Preventing contamination saves costs on water purchases, and expensive new source development Contact your regional DEP office for more information on Source Protection and the Waiver Program. Is of the system wells: Zone I - Milestone Wellfield #1 4197000-01G – Above ground storage of diesel fuel in the Zone I. Zone I Recommendations ü Consider switching from diesel to propane to reduce the risk of potential groundwater contamination. ü Keep any new non water supply activities from the Zone Is to comply with DEP’s Zone I requirements. ü Use BMPs for the storage, use, and disposal of hazardous materials such as water supply chemicals and maintenance chemicals. ü Do not use or store pesticides, fertilizers or road salt within the Zone Is. 2. Residential Land Uses – Residential land use is common throughout the Zone II. Approximately eighty five percent of the areas have public sewers, therefore, fifteen percent use septic systems. If managed imp roperly, activities associated with residential areas can contribute to drinking water contamination. Common potential sources of contamination include: · Septic Systems – Improper disposal of household hazardous chemicals to septic systems is a potential source of contamination to the groundwater because septic systems lead to the ground. If septic systems fail or are not properly maintained they can be a potential source of microbial contamination. · Household Hazardous Materials - Hazardous materials may include automotive wastes, paints, solvents, pesticides, fertilizers, and other substances. Improper use, storage, and disposal of chemical products used in homes are potential sources of contamination. · Heating Oil Storage - If managed improperly, Underground and Above ground Storage Tanks (UST and AST) can be potential sources of contamination due to leaks or spills of the fuel oil they store. · Stormwater – Catch basins transport stormwater from roadways and adjacent properties to the ground. As flowing stormwater travels, it picks up debris and contaminants from streets and lawns. Common potential contaminants include lawn chemicals, pet waste, and substances from automotive leaks, maintenance, washing, or accidents. Residential Land Use Recommendations ü Educate residents on best management practices (BMPs) for protecting water supplies. Distribute the fact sheet Residents Protect Drinking Water available in Appendix C and on www. mass.gov/dep/brp/dws/protect.htm, which provides BMPs for common residential issues. ü Work with planners to control new residential developments in the water supply protection areas. ü Promote BMPs for stormwater management and pollution controls. Visit DEP’s web site for additional August 2004 Source Water Assessment and Protection (SWAP) Report Page 4 What are "BMPs?" Best Management Practices (BMPs) are measures that are used to protect and improve surface water and groundwater quality. BMPs can be structural, such as oil & grease trap catch basins, nonstructural, such as hazardous waste collection days or managerial, such as employee training on proper disposal procedures. information and assistance at http://www.state.ma.us/dep/brp/wm/nonpoint. htm. 3. Transportation Corridors - Local roads are common throughout the Zone II. Roadway construction, maintenance, and typical highway use can all be potential sources of contamination. Accidents can lead to spills of gasoline and other potentially dangerous transported chemicals. Roadways are frequent sites for illegal dumping of hazardous or other potentially harmful wastes. De-icing salt, automotive chemicals and other debris on roads are picked up by stormwater and washed into catch basins. Transportation Corridor Recommendations ü Wherever possible, ensure that drains discharge stormwater outside of the Zone I. ü Identify stormwater drains and the drainage system along transportation corridors. If maps aren’t yet available, work with town officials to investigate mapping options such as the upcoming Phase II Stormwater Rule requiring some communities to complete stormwater mapping. ü Work with local emergency response teams to ensure that any spills within the Zone II can be effectively contained. Review storm drainage maps with emergency response teams. ü Work with the Town and State to best manage stormwater in the Zone II. Best management practices include street sweeping, vegetative swales, and regular catch basin inspection, cleaning and maintenance. 4. Hazardous Materials Storage and Use – Small areas of the Zone II are used for commercial or industrial land uses. Activities associated with commercial and industrial land use are often the greatest concern when evaluating water supply protection. Many small businesses and industries use hazardous materials, produce hazardous waste products, and/or store large quantities of hazardous materials in UST/AST. If hazardous materials are improperly stored, used, or disposed, they become potential sources of contamination. Hazardous materials should never be disposed of to a septic system or floor drain leading directly to the ground. Hazardous Materials Storage and Use Recommendations ü Educate local businesses on best management practices for protecting water supplies. Distribute the fact sheet Businesses Protect Drinking Water available in Appendix C and on www.mass.gov/dep/brp/dws/protect.htm, which provides BMP’s for common business issues. ü Work with local businesses to register those facilities that are unregistered generators of hazardous waste or waste oil. Partnerships between businesses, water suppliers, and communities enhance successful public drinking water protection practices. ü Educate local businesses on Massachusetts floordrain requirements. See brochure Industrial Floor Drains for more information. 5. Presence of Oil or Hazardous Material Contamination Site – The Zone II contains DEP (Continued on page 7) For More Information Contact Isabel Collins of DEP’s Southeast Regional Office at (508) 946-2726 for more information and assi stance on improving current protection measures. Copies of this report have been provided to the public water supplier, board of health, and the town. August 2004 Source Water Assessment and Protection (SWAP) Report Page 5 Potential Source of Contamination vs. Actual Contamination The activities listed in Table 2 are those that typically use, produce, or store contaminants of concern, which, if managed improperly, are potential sources of contamination (PSC). It is important to understand that a release may never occur from the potential source of contamination provided facilities are using best management practices (BMPs). If BMPs are in place, the actual risk may be lower than the threat ranking identified in Table 2. Many potential sources of contamination are regulated at the federal, state and/or local levels, to further reduce the risk. Table 2: Land Use in the Protection Areas (Zones I and II) For more information, refer to Appendix A: Regulated Facilities within the Water Supply Protection Area Activities Quantity Threat* Potential Source of Contamination Agricultural Nurseries 1 M Fertilizers, pesticides, and other chemicals: leaks, spills, improper handling, or over-application Commercial Car/Truck/Bus Washes 1 L Vehicle wash water, soaps, oils, greases, metals, and salts: improper management Auto Repair Shops 2 H Automotive fluids, vehicle paints, and solvents: spills, leaks, or improper handling Gas Stations 3 H Automotive fluids and fuels: spills, leaks, or improper handling or storage Boat Yards/Builders 1 H Fuels, paints, and solvents: spills, leaks, or improper handling Cemeteries 1 M Over-application of pesticides: leaks, spills, improper handling; historic embalming fluids Dry Cleaners 1 H Solvents and wastes: spills, leaks, or improper handling Laundromats 1 L Wash water: improper management Medical Facilities 1 M Biological, chemical, and radioactive wastes: spills, leaks, or improper handling or storage Nursing Homes 1 L Microbial contaminants: improper management Paint Shops 1 H Paints, solvents, other chemicals: spills, leaks, or improper handling or storage Photo Processors 2 H Photographic chemicals: spills, leaks, or improper handling or storage Sand And Gravel Mining/Washing 1 M Heavy equipment, fuel storage, clandestine dumping: spills or leaks Industrial Fuel Oil Distributors H Fuel oil: spills, leaks, or improper handling or storage Hazardous Materials Storage H Hazardous materials: spills, leaks, or improper handling or storage August 2004 Source Water Assessment and Protection (SWAP) Report Page 6 Notes: 1. When specific potential contaminants are not known, typical potential contaminants or activities for that type of land use are listed. Facilities within the watershed may not contain all of these potential contaminant sources, may contain other potential contaminant sources, or may use Best Management Practices to prevent contaminants from reaching drinking water supplies. 2.For more information on regulated facilities, refer to Appendix A: Regulated Facilities within the Water Supply Protection Area information about these potential sources of contamination. 3.For information about Oil or Hazardous Materials Sites in your protection areas, refer to Appendix B: Tier Classified Oil and/or Hazardous Material Sites. * THREAT RANKING - The rankings (high, moderate or low) represent the relative threat of each land use compared to other PSCs. The ranking of a particular PSC is based on a number of factors, including: the type and quantity of chemicals typically used or generated by the PSC; the characteristics of the contaminants (such as toxicity, environmental fate and transport); and the behav- ior and mobility of the pollutants in soils and groundwater. Table 2 Continued: Land Use in the Protection Areas (Zones I and II) For more information, refer to Appendix A: Regulated Facilities within the Water Supply Protection Area Activities Quantity Threat* Potential Source of Contamination Residential Fuel Oil Storage (at residences) numerous M Fuel oil: spills, leaks, or improper handling Lawn Care / Gardening numerous M Pesticides: over-application or improper storage and disposal Septic Systems / Cesspools numerous M Hazardous chemicals: microbial contaminants, and improper disposal (About 15% of the Zone II are on private septic) Miscellaneous Aboveground Storage Tanks numerous M Materials stored in tanks: spills, leaks, or improper handling Aquatic Wildlife some L Microbial contaminants Oil or Hazardous Material Sites 1 -- Tier Classified Oil or Hazardous Materials Sites are not ranked due to their site-specific character. Individual sites are identified Schools, Colleges, and Universities 1 M Fuel oil, laboratory, art, photographic, machine shop, and other chemicals: spills, leaks, or improper handling or storage Small quantity hazardous waste generators 2 M Hazardous materials and waste: spills, leaks, or improper handling or storage Stormwater Drains/ Retention Basins numerous L Debris, pet waste, and chemicals in stormwater from roads, parking lots, and lawns Underground Storage Tanks 3 H Stored materials: spills, leaks, or improper handling Utility Substation Transformers 2 L Chemicals and other materials including PCBs: spills, leaks, or improper handling August 2004 Source Water Assessment and Protection (SWAP) Report Page 7 Top 5 Reasons to Develop a Local Wellhead Protection Plan Œ Reduces Risk to Human Health • Cost Effective! Reduces or Eliminates Costs Associated With: w Increased groundwater monitoring and treatment w Water supply clean up and remediation w Replacing a water supply w Purchasing water Ž Supports municipal bylaws, making them less likely to be challenged • Ensures clean drinki ng water supplies for future generations • Enhances real estate values – clean drinking water is a local amenity. A community known for its great drinking water in a place people want to live and businesses want to locate. (Continued from page 4) Tier Classified Oil and/or Hazardous Material Release Site indicated on the map as Release Tracking Number 4-0006036. Refer to the attached map and Appendix B for more information. Oil or Hazardous Material Contamination Sites Recommendation ü Monitor progress on any ongoing remedial action conducted for the known oil or contamination sites. 6. Protection Planning – Currently, Nantucket has water supply protection controls that meet DEP’s Wellhead Protection regulations 310 CMR 22.21(2). Protection planning protects drinking water by managing the land area that supplies water to a well. A Wellhead Protection Plan coordinates community efforts, identifies protection strategies, establishes a timeframe for implementation, and provides a forum for public participation. There are resources available to help communities develop a plan for protecting drinking water supply wells. Protection Planning Recommendations ü Use Wellhead Protection Committee to implement goals of Wellhead Protection Plan. ü Coordinate efforts with local officials to compare local wellhead protection controls with current MA Wellhead Protection Regulations 310 CMR 22.21 (2). For more information on DEP land use controls see http://mass.gov /dep/ brp/dws/protect.htm. ü If local controls do not regulate floordrains, be sure to include floordrain controls that meet 310 CMR 22.21(2). ü Work with town boards to review and provide recommendations on proposed development within your water supply protection areas. To obtain information on build-out analyses for the town, see the Executive Office of Environmental Affairs' community preservation web site, http://commpres. env.state.ma.us/. Other land uses and activities within the Zone II include auto repair shops, gas stations, and a dry cleaner. Refer to Table 2 and Appendix A for more information about these land uses. Identifying potential sources of contamination is an important initial step in protecting your drinking water sources. Further local investigation will provide more in-depth information and may identify new land uses and activities that are potential sources of contamination. Once potential sources of contamination are identified, specific recommendations like those below should be used to better protect your water supply. Section 3: Source Water Protection Conclusions and Recommendations Current Land Uses and Source Protection As with many water supply protection areas, the Zone II contains potential sources of contamination. However, source protection measures reduce the risk of actual contamination, as illustrated in Figure 2. The water supplier is commended for taking an active role in promoting source protection measures in the Water Supply Protection Areas through: · having complete control over activities in the Zone Is for all three groundwater sources; · maintaining a good working relationship with Nantucket’s planning and zoning boards resulting in consideration of water supply protection issues as a part of the approval process for commercial or industrial development; and DRINKING WATER PROTECTION AREA August 2004 Source Water Assessment and Protection (SWAP) Report Page 8 Table 3: Current Protection and Recommendations Protection Measures Status Recommendations Does the Public Water Supplier (PWS) own or control the entire Zone I? YES Follow Best Management Practices (BMPs) that focus on good housekeeping, spill prevention, and operational practices to reduce the use and release of hazardous materials. Is the Zone I posted with “Public Drinking Water Supply” Signs? YES Additional economical signs are available from the Northeast Rural Water Association (802) 660-4988. Is Zone I regularly inspected? YES Continue regular inspections of drinking water protection areas. Are water supply-related activities the only activities within the Zone I? NO Continue to restrict non-water supply activities in Zone Is. Municipal Controls (Zoning Bylaws, Health Regulations, and General Bylaws) Does the municipality have Wellhead Protection Controls that meet 310 CMR 22.21(2)? YES The Nantucket’s “Aquifer Protection District” bylaw meets DEP’s requirements for wellhead protection. Refer to www.state.ma.us/dep/brp/dws/ for model bylaws and health regulations, and current regulations. Do neighboring communities protect the Zone II areas extending into their communities? N/A Work to protect Nantucket’s Sole Source Aquifer through island wide cooperation efforts. Planning Does the PWS have a Wellhead Protection Plan? YES Use Wellhead Protection Committee to implement goals of the Wellhead Protection Plan. Submit plan to DEP for approval. Does the PWS have a formal “Emergency Response Plan” to deal with spills or other emergencies? YES Augment plan by developing a joint emergency response plan with fire department, Board of Health, DPW, and local and state emergency officials. Coordinate emergency response drills with local teams. Does the municipality have a wellhead protection committee? YES Ensure committee includes representatives from citizens’ groups and the business community. Does the Board of Health conduct inspections of commercial and industrial activities? YES For more guidance see “Hazardous Materials Management: A Community's Guide” at www.state.ma.us/ dep/brp/dws/files/hazmat.doc. Does the PWS provide wellhead protection education? YES Aim additional efforts at commercial, industrial and municipal uses within the Zone II. Zone I August 2004 Source Water Assessment and Protection (SWAP) Report Page 9 · persuading Nantucket to approve bylaws that meet DEP’s wellhead protection controls found in 310 CMR 22.21(2). Source Protection Recommendations ü Continue regular Zone I inspections, and when feasible, remove any non- water supply activities. ü Convert all backup power sources to propane. ü Educate residents on ways they can help you to protect drinking water sources. ü Work with emergency response teams to ensure that they are aware of the stormwater drainage in your Zone II and to cooperate on responding to spills or accidents. ü Partner with local businesses to ensure the proper storage, handling, and disposal of hazardous materials. ü Monitor progress on any ongoing remedial action conducted for the known oil or contamination sites. ü Continue to implement your Wellhead Protection Plan. Conclusions These recommendations are only part of your ongoing local drinking water source protection. Additional source protection recommendations are listed in Table 3, the Key Issues above and Appendix C. DEP staff, informational documents, and resources are available to help you build on this SWAP report as you continue to improve drinking water protection in your community. Grants and loans are available through the Drinking Water State Revolving Loan Fund, the Clean Water State Revolving Fund, and other sources. For more information on grants and loans, visit the Bureau of Resource Protection’s Municipal Services web site at: http://mass.gov/dep/brp/mf/mfpubs. htm. The assessment and protection recommendations in this SWAP report are provided as a tool to encourage community discussion, support ongoing source protection efforts, and help set local drinking water protection priorities. Citizens and community officials should use this SWAP report to spur discussion of local drinking water protection measures. The water supplier should supplement this SWAP report with local information on potential sources of contamination and land uses. Local information should be maintained and updated periodically to reflect land use changes in the Zone II. Use this information to set priorities, target inspections, focus education efforts, and to develop a long-term drinking water wellhead protection plan. Section 4: Appendices A. Regulated Facilities within the Water Supply Protection Area B. Table of Tier Classified Oil and/or Hazardous Material Sites within the Water Supply Protection Areas C. Additional Documents on Source Protection What is a Zone III? A Zone III (the secondary recharge area) is the land beyond the Zone II from which surface and ground water drain to the Zone II and is often coincident with a watershed boundary. The Zone III is defined as a secondary recharge area for one or both of the following reasons: 1. The low permeability of underground water bearing materials in this area significantly reduces the rate of groundwater and potential contaminant flow into the Zone II. 2. The groundwater in this area discharges to a surface water feature such as a river, rather than discharging directly into the aquifer. The land uses within the Zone III are assessed only for sources that are shown to be groundwater under the direct influence of surface water. Additional Documents: To help with source protection efforts, more information is available by request or online at mass.gov/dep/brp/dws including: 1. Water Supply Protection Guidance Materials such as model regulations, Best Management Practice information, and general water supply protection information. 2. MA DEP SWAP Strategy 3. Land Use Pollution Potential Matrix 4. Draft Land Use/Associated Contaminants Matrix Page 1 of 3 APPENDIX A: REGULATED FACILITIES WITHIN THE WATER SUPPLY PROTECTION AREA DEP Permitted Facilities DEP Facility Number Facility Name Street Address Town Permitted Activity Activity Class 37709 NANTUCKET AUTOMOTIVE 12 BOYNTON LN NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste 54429 WALTER J GLOWACKI & SONS INC OLD SOUTHROAD NANTUCKET Plant Air Quality Permit 54429 WALTER J GLOWACKI & SONS INC OLD SOUTH RD NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Waste Oil or PCBs 131043 HARBOR FUEL OIL 155 SPARKS AVE NANTUCKET Toxics Use Reduction Filer Below Toxics Use Reduction Regulated Levels 131043 HARBOR FUEL OIL CORP 15 SPARKS AVE NANTUCKET Plant Air Quality Permit 131043 HARBOR FUEL OIL 15 SPARKS AVE NANTUCKET Sewer Connection or Groundwater Discharge Below Industrial Waste Water Regulated Levels 131043 HARBOR FUEL OIL CORP 15 SPARKS AVE NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste 132137 NANTUCKET ELECTRIC COMPANY 2 FAIRGROUNDS RD NANTUCKET Plant Air Quality Permit 132137 NANTUCKET ELECTRIC CO FAIRGROUNDS RD NANTUCKET Generator of Hazardous Waste Small Quantity Generator 132137 NANTUCKET ELECTRIC CO FAIRGROUNDS RD NANTUCKET Generator of Hazardous Waste Large Quantity Generator of Hazardous Waste 132138 NANTUCKET AUTO BODY INC 36 SPARKS AVE NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste 132139 ISLAND RESTORATION MADAKET RD NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste 132140 ALLEN DON AUTO SERVICE INC POLPIS RD NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste 132750 HOLDGATES ISLAND LAUNDRY 4 VESPER LN NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste Page 2 of 3 DEP Facility Number Facility Name Street Address Town Permitted Activity Activity Class 132750 HOLDGATES ISLAND LAUNDRY 4 VESPER LN NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste 132751 NANTUCKET COTT HOSP 57 PROSPECT ST NANTUCKET Plant Air Quality Permit 132752 NANTUCKET HIGH SCHOO ATLANTIC AVE NANTUCKET Plant Air Quality Permit 137088 BUTNELL CORPORATION 127 ORANGE ST NANTUCKET Fuel Dispenser Fuel Dispenser 137089 D & B AUTO SERVICE INC 41 SPARKS AVE NANTUCKET Fuel Dispenser Fuel Dispenser 137090 ON ISLAND GAS INC 34 SPARKS AVE NANTUCKET Fuel Dispenser Fuel Dispenser 314966 POETS CORNER PRESS 2 BARTLETT RD NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste 314966 POETS CORNER PRESS 2 BARTLETT RD NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste 364014 NANTUCKET FIRE DEPT 131 PLEASANT ST NANTUCKET Fuel Dispenser Fuel Dispenser 368831 MIKE LAMB INC 149 HUMMOCK POND RD NANTUCKET Generator of Hazardous Waste Very Small Quantity Generator of Hazardous Waste Page 3 of 3 Underground Storage Tanks Facility Name Address Town Tank Material Tank Type Tank Leak Detection Capacity (gal) Contents D & B AUTO SERVICE INC ID #11610 41 SPARKS AVE NANTUCKET Reinforced 2 Walls Interstitial Monitoring 10000 Gasoline Reinforced 2 Walls Interstitial Monitoring 10000 Gasoline/D HATCH'S GAS ID #83319 129 ORANGE ST NANTUCKET Cathodic 2 Walls Interstitial Monitoring 10000 Gasoline ISLAND MARINE SERVICE INC ID #40240 96 WASHINGTON ST EXT NANTUCKET Epoxy Coat 1 Wall Inventory Record-Keeping 1000 Diesel NANTUCKET ELECTRIC CO ID #16715 2 FAIRGROUNDS RD NANTUCKET Steel N/A N/A 500 Waste Oil ON ISLAND GAS ID #16722 34 SPARKS AVE NANTUCKET Composite 2 Walls Interstitial Monitoring 15000 Gasoline VERIZON MASSACHUSETTS ID #11604 3 UNION ST NANTUCKET Reinforced 2 Walls Interstitial Monitoring 500 Diesel For more information on underground storage tanks, visit the Massachusetts Department of Fire Services web site: http://www.state.ma.us/dfs/ust/ustHome.htm Note: This appendix includes only those facilities within the water supply protection area(s) that meet state reporting requirements and report to the appropriate agencies. Additional facilities may be located within the water supply protection area(s) that should be considered in local drinking water source protection planning. 1 of 1 APPENDIX B – Table of Tier Classified Oil and/or Hazardous Material Sites within the Water Supply Protection Areas DEP’s datalayer depicting oil and/or hazardous material (OHM) sites is a statewide point data set that contains the approximate location of known sources of contamination that have been both reported and classified under Chapter 21E of the Massachusetts General Laws. Location types presented in the layer include the approximate center of the site, the center of the building on the property where the release occurred, the source of contamination, or the location of an on-site monitoring well. Although this assessment identifies OHM sites near the source of your drinking water, the risks to the source posed by each site may be different. The kind of contaminant and the local geology may have an effect on whether the site poses an actual or potential threat to the source. The DEP’s Chapter 21E program relies on licensed site professionals (LSPs) to oversee cleanups at most sites, while the DEP’s Bureau of Waste Site Cleanup (BWSC) program retains oversight at the most serious sites. This privatized program obliges potentially responsible parties and LSPs to comply with DEP regulations (the Massachusetts Contingency Plan – MCP), which require that sites within drinking water source protection areas be cleaned up to drinking water standards. For more information about the state’s OHM site cleanup process to which these sites are subject and how this complements the drinking water protection program, please visit the BWSC web page at http://www.state.ma.us/dep/bwsc. You may obtain site - specific information two ways: by using the BWSC Searchable Sites database at http://www.state.ma.us/dep/bwsc/sitelist.htm, or you may visit the DEP regional office and review the site file. These files contain more detailed information, including cleanup status, site history, contamination levels, maps, correspondence and investigation reports, however you must call the regional office in order to schedule an appointment to view the file. The table below contains the list of Tier Classified oil and/or Hazardous Material Release Sites that are located within yo ur drinking water source protection area. Table 1: Bureau of Waste Site Cleanup Tier Classified Oil and/or Hazardous Material Release Sites (Chapter 21E Sites) - Listed by Release Tracking Number (RTN) RTN Release Site Address Town Contaminant Type 4-0006036 129 ORANGE ST NANTUCKET Oil For more location information, please see the attached map. The map lists the release sites by RTN. * Site recently classified, not reflected in current GIS map. Nantucket, MA (project #225139)Woodard & Curran CWMP Update September 2014 APPENDIX E: NANTUCKET SEWER ACT BOARD OF HEALTH LOCAL REGULATIONS BOARD OF HEALTH ADMINISTRATIVE CONSENT ORDER SEPTIC MANAGEMENT PLAN DOCUMENTS TOWN OF NANTUCKET BOARD OF HEALTH REGULATIONS AFFECTING MADAKET LOCAL REGULATION 51.00 In order to preserve, protect, and manage the quality and supply of fresh water, and to protect the health and welfare of the inhabitants of the town of Nantucket, the following regulations are hereby adopted by the Board of Health of the Town of Nantucket, pursuant to authority granted by General Laws, Chapter 111, Section 31 on September 19, 1973, to be effective upon publication. 51.01SUBJECT AREA. A. These Regulations shall be applicable in that part of the Town of Nantucket known as Madaket, more particularly described to be within the area bounded by the center line of Hither Creek; the center line of Cambridge Street ; Madaket Harbor; Broad creek; and the Atlantic Ocean. 51.02 DISTANCES. A. In any part of said area where the percolation rate is two minutes or less per inch, the distance between the soil absorption system, and any potable water supply well, shall be one hundred and fifty (150) feet, not withstanding the fact that such a system or well is located on an adjacent lot of land. B. The distance of a soil absorption system from a property line shall be fifty (50) feet. Where the property abuts a road way or other land restricted from building, the width of the road way or restricted land can be included as part of the 50-foot set-back requirement. No soil absorption system may be located closer than 10 feet to any property line. C. Every soil absorption system shall have a one hundred percent (100%) reserve area which shall be no closer than fifteen (15) feet to such a soil absorption system. TOWN OF NANTUCKET BOARD OF HEALTH REGULATIONS: INSPECTION AND UPGRADING OF SUBSTANDARD ONSITE SEWAGE DISPOSAL SYSTEMS WITHIN THE MADAKET HARBOR WATERSHED LOCAL REGULATIONS - SECTION 53.00 53.00 Inspection and upgrading of on-site sewage disposal systems. A. Purpose. Whereas ongoing research by the Town of Nantucket in co-operation with the Commonwealth of Massachusetts Department of Environmental Protection has documented increasing levels of nutrient loading in the Madaket Harbor/Hither Creek watershed system, these Regulations are promulgated to further limit said nutrient and other sources of contamination loading and to protect and enhance the quality of groundwater flowing into and affecting Nantucket’s harbor waters. B. Authority. These Regulations are adopted by the Town of Nantucket’s Board of Health as authorized by Massachusetts General Laws, Chapter 111, Section 31. 53.01 Definition A. Madaket Harbor Watershed. The area constituting the watershed for Madaket Harbor/Hither Creek, as delineated on a map entitled “Madaket Harbor Watershed with Sub-Areas,” Nantucket GIS, dated January 13, 2003. 53.02 Compliance Requirements A. Properties utilizing in-ground soil absorption systems located within Zone A of the Madaket Harbor Watershed District as established by these Regulations and as demonstrated on a map titled Madaket Harbor Watershed District shall have the existing soil absorption system inspected by a Massachusetts licensed system inspector within 42 months of promulgation of these Regulations. Said Inspection Report shall be recorded with the Nantucket Health Department within 21 days of the completed inspection. B. Properties utilizing in-ground soil absorption systems located within Zone B of the Madaket Harbor Watershed District as established by these Regulations and as demonstrated on a map entitled Madaket Harbor Watershed District shall have the existing soil absorption system inspected by a Massachusetts licensed system inspector within 48 months of promulgation of these Regulations. Said Inspection Report shall be recorded with the Nantucket Health Department within 21 days of the completed inspection. 53.03 Inspections. A. All systems shall be inspected to determine the presence and/or absence of hydraulic failure and depth to ground water. Depth to ground water shall be determined by direct observation of highest ground water elevation ( including seasonal perched and tidally influenced ground water) in a test pit excavation, unless an alternative method for accurately determining the depth to ground water has been approved in writing by the Health Director. B. The Health Director may, based on unique development conditions or due to the proximity of multiple systems within a limited geographic area, substitute a pre-approved ground water monitoring protocol for test pit excavation. The monitoring protocol shall require as a minimum; - data collected over a 12 month period - a minimum of 3 wells offset to define ground water flow direction as well as depth. 53.04 Repairs to failed systems A. The owner of a system meeting hydraulic failure criteria pursuant to these regulations as stated on the Town of Nantucket Board of Health Septic System Inspection Report/Certificate of Compliance Form shall bring the system into compliance with all applicable state and local regulations within 30 days of the date of inspection. B. The owner of a system meeting failure criteria, exclusive of hydraulic failure, pursuant to these Regulations as stated on the Town of Nantucket Board of Health Septic System Inspection Report/Certificate of Compliance Form shall bring the system into compliance with all state and local regulations within 18 months of the adoption of the Assessment Report required in 53.05 and/or within 30 months of the expiration date of Zone A and B inspections. 53.05 Inspection evaluation period A. Within three months of the inspection date of Zone A and B inspections, the Health Department shall tabulate and publish the inspection results. B. Within six months of the expiration date of zone A and Zone B inspections, the Health Department shall provide a preliminary assessment report to the Board of Health. This report shall include a brief evaluation of treatment options to effectuate implementation of best available engineering design for all required repairs/upgrades. C. No later than six months of the expiration date of Zone B inspections, the Board of Health shall adopt the Nantucket/Madaket Assessment Report, including recommendations. 53.04 Exemptions A. Properties whose onsite sewage disposal design is documented to be based on test pit and percolation testing observed by the Board of Health after November 1st 2003. B. Properties which have been inspected and have both a Town of Nantucket Board of Health Septic System Inspection Report and a Certificate of Compliance Form filed with the Nantucket Health Department and dated within 24 months before promulgation of these Regulations are exempt from inspection and compliance standards as set forth in these Regulations. C. In all areas where Town of Nantucket mapping shows that the separation between the bottom of the soil absorption system and the predicted groundwater elevation (based on Horsley/Whitten/Hegeman study and/or USGS Hydrologic Investigation Atlas Water resources Map 1980) exceeds ten (10) feet, documentation of high ground water levels shall not be required. 53.07 Enforcement A. Enforcement of these Local Regulations shall be effected through Town of Nantucket Board of Health Local regulations 67.00 Miscellaneous Provisions. B. These Regulations and the amendments thereto shall become effective upon the date of publication Nantucket Board of Health Whitey Willauer, Chairman ______________________ Patricia Roggeveen Brian Chadwick Michael Kopko Allen Reinhard Effective Date June 14, 2006 Amended Date November 28, 2007 End of Inspection period for Zone A – December 14 2009 End of Inspection Period for Zone B – June 14 2010 51.03 SYSTEM LOCATION ON LOT. A. Every on site system and potable water supply well shall be on the same lot of land as the building, dwelling, facility, or structure which they serve. 51.04 CERTIFICATE OF COMPLIANCE & WATER TEST. A. No well shall be connected to the water distribution system of any dwelling or other building without a Certificate of Compliance issued by the Board of Health that said potable well and water distribution system does not endanger the health of any potential user. Prior to the issuance of such a Certificate of Compliance, the applicant therefore shall provide the Board of Health with proof of a satisfactory bacteriological and chemical analysis of the water from such a well. TOWN OF NANTUCKET BOARD OF HEALTH LOCAL REGULATION 54.00 SEPTIC WASTE WATER FLOW LIMITATIONS WITHIN MADAKET HARBOR WATERSHED PROTECTION DISTRICT 54.00 Purpose: Whereas ongoing research by the Town of Nantucket in co-operation with the Commonwealth of Massachusetts’s Department of Environmental Protection has documented increasing levels of nutrient loading with resultant degradation of water quality within the Madaket Harbor/Hither Creek watershed system, these Regulations are promulgated to maintain and/or restrict additional effluent flows which may further degrade Madaket Harbor/Hither Creek water quality through increased nutrient loading. 54.01 Definitions: Madaket Harbor Watershed Protection District –The area constituting the watershed for Madaket Harbor / Hither Creek, as delineated on a map entitled “Madaket Harbor Watershed with Sub Areas” Nantucket GIS, as dated January 13, 2003. Nitrogen Sensitive Area – Areas that have been determined by the Nantucket Board of Health to be particularly sensitive to the discharge of pollutants from on site sewage disposal systems, including nitrogen, nitrogen as nitrate, phosphorous and pathogens. Such areas are depicted on a plan entitled “Board of Health Nitrogen Sensitive Areas” which is hereby incorporated by reference herein, and as such warrant the imposition of the loading restrictions set forth within these regulations. 54.02 Effluent flows within Madaket Harbor Watershed Protection District: A. All properties currently existing or created and located within the Madaket Harbor Watershed Protection District as defined within these regulations shall not be constructed or re-constructed to receive design flows over 110 gallons of effluent for every 10,000 feet of lot area. The use of abutting roads and right of ways, to a property shall not be considered in calculating the permissible effluent flows for the subject property. B. Existing developed properties shall be allowed to repair/replace existing subsurface disposal systems for existing flows determined by a qualified licensed Massachusetts professional with nutrient reducing technologies or technologies acceptable to the Nantucket Board of Health as deemed appropriate. C. Properties connected to a municipal water service shall not be exempted from compliance with Section 54.02 (A) of these regulations. 54.03 Modification or rescinding of regulations: A. No part of these regulations may be modified and/or rescinded without a majority vote of Town of Nantucket Board of Health. 54.04 Enforcement: A. Without limiting any other available remedies or penalties, the Board of Health may punish any person or entity that violates these regulations by assessing a penalty of $300.00. Each day or part thereof which violation occurs or continues shall constitute a separate offense. As an alternative to criminal prosecution or civil action, the non-criminal disposition procedure set forth in M.G.L. c40, Section 21D, and Sections 1-2, 1-3, 1-4, 1-5, and 1-6 of the Code of the Town of Nantucket may be used with a penalty of $300.00 for each violation, each day or part thereof during which such violation occurs or continues constituting a separate offense. The Health Director and Assistant Health Officer are hereby empowered to enforce this Section 54.00. 54.05 Authority: These regulations are adopted by the Town of Nantucket’s Board of Health as authorized by Massachusetts General Laws, Chapter 111, Section 31. ________________________ Michael Kopko – Chairman – Nantucket Board of Health ________________________ Patricia Roggeveen ________________________ Brian Chadwick ________________________ Approved: August 24, 2009 Alan Reinhard ________________________ Attest______________________ Rick Atherton Catherine Stover – Town Clerk TOWN OF NANTUCKET BOARD OF HEALTH REGULATIONS: INSPECTION AND UPGRADING OF SUBSTANDARD ONSITE SEWAGE DISPOSAL SYSTEMS WITHIN THE HUMMOCK POND WATERSHED PROTECTION DISTRICT LOCAL REGULATION – 55.00 55.00 Inspection and upgrading of onsite sewage disposal systems A. Purpose. Whereas ongoing research by the Town of Nantucket in co-operation with the Commonwealth of Massachusetts Department of Environmental Protection has documented increasing levels of nutrient loading in the Hummock Pond watershed system, these Regulations are promulgated to further limit said nutrients and other sources of contamination loading, and to protect and enhance the quality of groundwater flowing into and affecting the waters of Hummock Pond. B. Authority. These Regulations are adopted by the Town of Nantucket’s Board of Health as authorized by Massachusetts General Laws, Chapter 111, Section 31. 55.01 Definition. A. Hummock Pond Watershed Protection District. The area constituting the watershed for Hummock Pond as delineated on a map entitled Hummock Pond Watershed, Nantucket GIS, dated July 1, 2010. 55.02 Compliance Requirements. A. Properties utilizing in-ground soil absorption systems located within Zone A of the Hummock Pond Watershed Protection District as established by these Regulations, and as demonstrated on a map titled Hummock Pond Watershed Protection District, as established by these Regulations, shall have the existing soil absorption system(s) inspected by a Massachusetts licensed system inspector prior to March 1, 2014. Said Inspection Report shall be recorded with the Nantucket Health department within 21 days of the completed inspection. B. Properties utilizing in-ground soil absorption systems located within Zone B of the Hummock Pond Watershed Protection District as established by these Regulations and as demonstrated on a map entitled Hummock Pond Watershed Protection District shall have their existing soil absorption system(s) inspected by a Massachusetts licensed system inspector prior to June 1, 2014. Said Inspection report shall be recorded with the Nantucket Health Department within 21 days of the completed inspection. 55.03 Inspections. A. All systems shall be inspected to determine the presence and/or absence of hydraulic failure and depth to groundwater. Depth to groundwater shall be determined by direct observation of highest groundwater elevation (including seasonal perched and tidally influenced groundwater) in a test pit excavation, unless an alternative method for accurately determining the depth to groundwater has been approved in writing by the Health Director. B. The Health Director may, based on unique development conditions or due to the proximity of multiple systems within a limited geographic area, substitute a pre-approved groundwater monitoring protocol for test pit excavation. This monitoring protocol shall require a minimum; - Data collected over a 12 month period - A minimum of three wells off set to define groundwater flow direction as well as depth 55.04 Repairs to failed systems. A. The owner of a system meeting hydraulic failure criteria pursuant to these Regulations as stated on the Town of Nantucket Board of Health Septic System Inspection Report/Certificate of Compliance Form shall bring the system into compliance with all applicable state and local regulations within 60 days of the date of the inspection. B. The owner of a system meeting failure criteria, exclusive of hydraulic failure, pursuant to these Regulations as stated on the Town of Nantucket Board of Health Septic System Inspection Report/Certification of Compliance Form shall bring the system into compliance with all state and local regulations within 18 months of the adoption of the Assessment report required in 55,05 and/or within 30 months of the expiration date of Zone A and B inspections. 55.05 Inspection evaluation period. A. Within three months of the inspection expiration date of Zones A & B, the Health Department shall tabulate and publish the inspection results. B. Within six months of the inspections expiration date of Zones A & B, the Health Department shall provide a preliminary assessment report to the Board of Health. This report shall include a brief evaluation of treatment options to effectuate implementation of best available engineering design for all required repairs/upgrades. C. No later than six months following the expiration date of Zone B inspections, the Board of Health shall adopt the Hummock Pond Watershed Protection Area Assessment Report, including recommendations. 55.06 Exemptions. A. Properties whose onsite sewage disposal design is documented to be based on test pit and percolation testing observed by the Board of Health after June 1, 2008. B. Properties which have been inspected and have both a Town of Nantucket Board of Health Septic System Inspection Report and a Certificate of Compliance Form filed with the Nantucket Health Department and dated within 24 months prior to promulgation of these Regulations are exempt from inspection and compliance standards as set forth in these Regulations. 55.07 Enforcement. A. Enforcement of these Local Regulations shall be effective through Town of Nantucket Board of Health Local Regulations 67.00 Miscellaneous Provisions. B. These Regulations and any amendments thereto shall become effective upon the date of publication. Nantucket Board of Health _______________________________ Patricia Roggeveen, Chairman _______________________________ Michael Kopko ________________________________ Brian Chadwick ________________________________ Whitey Willauer ________________________________ Rick Atherton Effective date: September 2, 2010 Amended: February 21, 2013 TOWN OF NANTUCKET – BOARD OF HEALTH LOCAL REGULATIONS 59.00 – SEPTIC SYSTEM UPGRADES DEFERRALS 59.01 Purpose The Town is mandated through the Massachusetts Estuaries Program (MEP), under the jurisdiction of the Massachusetts Department of Environmental protection (MassDEP), to reduce nitrogen loading in specific areas of Nantucket and to meet Total Maximum Daily Loads (TMDL’s) set by the commonwealth in Nantucket harbor, Madaket harbor, Long Pond, Sesachacha Pond and potentially other embayment areas of Nantucket, including the Hummock Pond Area. Nantucket’s harbor watershed Districts (Nantucket & Madaket) also detail reductions of nutrient loading from on-site waste water disposal systems. In order to meet these mandates, the Town is currently engaged in facilities planning for future phases of a municipal Comprehensive Wastewater Management Plan (CWMP), which includes provisions for additional sewering of portions of the Town. Because the planning design and installation of sewers in these new areas is expected to take some time, the Board of Health wishes to provide options for property owners who currently have failed on-site waste water systems in areas proposed for municipal sewer. Therefore to alleviate the burden on property owners who may have to pay for an expensive septic system upgrade, replacement or repair and then have to pay again to connect to the municipal sewer, the Board is enacting this regulation to provide for deferrals in certain circumstances’. 59.02 Septic System Upgrade, Replacement or Repair deferrals 1. Owners or Operators of residential or commercial property on the Island of Nantucket shall upgrade, replace, or repair any on-site waste water disposal system that fails to meet the requirements of the State Environmental Code, Title 5, the Nantucket Board of Health Regulations, and/or orders of the Nantucket Board of Health, within the time required by such code, regulations, and/or orders. 2. The Board of health may defer any requirement to upgrade, replace, or repair a failing on-site wastewater disposal system until such time as a municipal sewer is available, for Owners and Operators of residential and commercial property located in a proposed future municipal sewer service area, identified as a Needs Area in the CWMP Update. 3. Any such deferrals shall be subject to the conditions set forth in section 59.03 of this regulation and the terms of an Administrative Consent order (ACO) executed by the owner and operator of the property. 59.03 Deferral Conditions 1. The issuance of a deferral shall be at the sole discretion of the Board of health, which shall determine that the costs of upgrading, replacing, or repairing the System is excessive in light of the probability that Municipal Sewer will be available in the near future and that such upgrade, replacement, or repair can be deferred for a definite period of time without creating an unreasonable threat to public health, safety, or the environment. 2. All upgrade deferrals shall be subject to the following minimum conditions: a. The applicant must demonstrate that the system is not in Hydraulic Failure, as that term is defined in Section 59.05 of this regulation and that the condition of the System does not pose an imminent threat to public health, safety, or the environment; b. The applicant must execute an Administrative Consent Order (ACO) acknowledging that the system fails to meet the requirements of the State Environmental Code, Title 5, the Nantucket Board of Health regulations and/or orders of the Nantucket Board of Health; c. The Applicant shall agree, in writing, to abandon the system and connect the property to the Municipal Sewer within sixty (60) days of receipt of notice of Sewer Availability, or to upgrade, repair or replace the System as required by the Board of Health, within sixty (60) days of receipt of notice that such upgrade, repair, or replacement is required; d. The Applicant shall deposit a sum of money into an insured and interest-bearing escrow account of the Town established and maintained by the Finance Director pursuant to G.L. c.44 Subsection 53A, said sum to be used solely for the purpose of defraying the cost of connecting to Municipal Sewer or upgrading, repairing, or replacing the system; e. The Applicant shall agree to have the system periodically inspected by a duly licensed Title 5 Inspector; f. The Applicant shall agree to comply with all interim orders of the Board of Health; and g. Said Administrative Consent Order shall be recorded with the title to the Property and shall run with the land. 59.04 Deferral Procedure 1. Any property owner seeking a deferral in accordance with Section 59.02 of this regulation shall apply, in writing, to the Board of Health. 2. The Application shall include an Inspection Report from a Duly licensed Title 5 Inspector showing the nature of the failure. 3. If the Applicant is approved, the Applicant shall execute an Administrative Consent Order and shall pay, by certified check, bank or cashiers check, a sum of money for the escrow account required by Section 59.03(2)(d) of this Regulation. 4. Within fourteen days (14) of the execution of the ACO, the Applicant shall provide the Board of health with proof that it has been recorded with the Nantucket County Registry of Deeds. 5. The Applicant shall make any interim repairs required by the Board of Health within the time ordered by the Board. 6. If the Applicant is denied, the Applicant may request a hearing before the Board of Health. Said request, shall be in writing, and shall be received by the Board no later than thirty (30) days after the Boards decision to deny the Application. The Board’s decision after said hearing shall be final. 59.05 Definitions a. Administrative Consent Order – Duly executed and recorded document that affords a property owner in a specific area of Nantucket to defer major repair and /or upgrade of a failed on-site wastewater treatment system until Municipal sewer is available for connection. Specific provisions for deferment are detailed in the ACO Document. b. Board of Health – The Town of Nantucket Department with local jurisdiction of on-site wastewater systems in addition to all other health- related matters. c. Comprehensive Wastewater Management Plan – The Town’s 20 year wastewater planning document completed according to the Department of Environmental Protection Bureau of Municipal Finances guide to Comprehensive Wastewater Management Planning, January 1996. d. Escrow Account – Account set up with the Town’s Finance Department for the purpose of collecting funds, based on an estimate to repair failed on-site wastewater system to Title 5 and local standards, to apportion towards the capital cost assessed to the property owner for municipal sewer or for repair/upgrade of on-site system. e. Hydraulic Failure – An onsite wastewater system failure due to ponding of surface water, back-up of sewage into the dwelling and/or evidence of flooding within the wastewater system’s distribution box, septic tank, cesspool, or metal tank. f. Massachusetts Department of Environmental Protection – The Massachusetts Department of Environmental Protection (MassDEP) is a name used for the agency charged with proposing and enforcing environmental law. g. Massachusetts Estuaries Program – The Massachusetts DEP and the UMASS/Dartmouth School of marine Science and Technology (SMAST) collaborating together with Coastal Zone Management, The Cape Cod Commission, and several municipalities to classify the nitrogen sensitivity of Southeastern Massachusetts’s coastal bays and estuaries. SMAST technical experts work with MassDEP to evaluate the nitrogen sensitivity through comprehensive water quality testing, quantitative TMDL (Total Maximum Daily Load) model, and preparation of technical reports allowing communities to consider how implementation of nitrogen management scenarios within water sheds will influence water quality in embayments. h. Municipal Sewer – The physical infrastructure that collects, treats, and discharges wastewater through a public system. i. Nantucket – “Nantucket” encompasses the land and water of the Town and County of Nantucket including Tuckernuck and Muskeget. j. Nantucket County Registry of Deeds – The County of Nantucket office of recorder of deeds is a government office tasked with maintaining public records and documents, especially records relating to real estate. k. Needs Area – Geographic delineation of land/property area that has been determined to be unsustainable in the long-term with on-site wastewater disposal systems in the Town of Nantucket’s Comprehensive Wastewater Management Plan. l. Technical Failure – An on-site wastewater system failure due to diminished distance To groundwater, less than 6 feet in designated watershed Protection zones, less than 5 feet in non-watershed protection areas/within 100 feet to private drinking water well, missing or undersized system components and leach fields within 100 feet of a private drinking water well. m. Title 5 – The environmental code in Massachusetts governing on-site wastewater systems in Massachusetts found under 310 CMR 15.00. n. Total Maximum Daily Load / TMDL – “Total maximum Daily Load / TMDL” is a calculation of the maximum amount of a pollutant that a waterbody can receive and still safely meet water quality standards o. Town – “Town” means the bodies politic created by statute (of the Commonwealth of Massachusetts General Court) to govern said lands and waters. 59.06 Modifications No part of these Regulations may be modified and/or rescinded without a majority vote of the Board of Health. 59.07 Enforcement Without limiting any other remedies or penalties, the Board of Health and/or the Board of Health’s Agent may punish any person or entity that violates these Regulations by assessing without demand a stipulated penalty of $500.00 per day. Each day of non-compliance shall constitute a separate violation. Penalty shall be paid by certified check, cashier’s check or money order payable to the Town of Nantucket. 59.08 Authority These Regulations are adopted by the Town of Nantucket’s Board of Health as authorized by Massachusetts General Laws Chapter 111, Section 31. ___________________________________ Patricia Roggeveen – Chair Nantucket Board of Health ___________________________________ Malcolm MacNab MD,PhD ___________________________________ Helene Weld RN ___________________________________ James Cooper ___________________________________ Stephen Visco Approved:_____________________ Attest:_________________________ Catherine Stover – Town Clerk TOWN OF NANTUCKET BOARD OF HEALTH REGULATIONS ON SITE SEWAGE DISPOSAL SYSTEMS LOCAL REGULATION 64.00 64.00 ON SITE SEWAGE DISPOSAL SYSTEMS A. Purpose The purpose of these regulations is to protect the public health and general welfare by regulating onsite soil absorption systems in a manner which will protect the quality of the Town of Nantucket’s groundwater and surface waters. These regulations are intended to compliment Title Five of the State Environmental Code. B. Authority These regulations are adopted pursuant to the authority granted to the Board by Massachusetts General Laws, Chapter 111 Section 31. C. Preamble The Board has determined that the State Environmental Code Title Five - Minimum Requirements for the Subsurface Disposal of Sanitary Sewage is not adequate to protect ground and surface waters from contamination by nutrients, bacteria, viruses, and hazardous materials associated with septic systems effluent, particularly in areas with extremely rapid infiltration rates, and in coastal areas characterized by tidally induced ground water fluctuations, coastal flooding, and shifting sand. 1 64.01 GENERAL REQUIREMENTS FOR INDIVIDUAL DISPOSAL SYSTEMS. A. Disposal Works Construction Permit, No individual on site septic system or other means of sewage disposal, shall be located, constructed, altered, repaired, or installed where a common sanitary sewer is accessible adjoining the property and where permission to enter such sewer can be obtained from the Nantucket Board of Public Works having jurisdiction over it (310 CMR 15.00) or if a common sanitary sewer is not accessible until a permit for an on site system’s location, construction, alteration, repair or installation shall have been issued by the Board of Health. A permit shall not be issued for any system of individual sewage disposal when the total volume of the sewage to be disposed of on any lot is in excess of 10,000 gallons per day, or where an on site system is proposed on the lot to be served, until the plans for such system have been approved by the Massachusetts Department Of Environmental Protection in accordance with M.G.L., C 111 section 17. Where sewage flows on a lot exceed 10,000 gallons per day, the Department of Environmental Protection may require additional treatment of the waste prior to its disposal to the ground. The applicant is also obligated to comply with any applicable requirements established by the Division of Water pollution Control pursuant to M.G.L., C.21 section 43, and the Wetlands Protection Act M.G.L., C. 131 section 40. A permit shall not be issued in designated Nantucket Nitrogen, Phosphorous and/or Pathogen Sensitive Areas except as provided in the Town of Nantucket Board of Health Regulations 64.04. B. Application for Disposal Works Construction Permit. An application for a Disposal Works Construction Permit shall be submitted to the Board of Health and must be accompanied by a plan stamped by a qualified licensed professional engineer or Registered Sanitarian. The Board shall revoke such permit if conditions different from those set forth in the application are found to exist prior to or during actual construction of the system. The permit so granted shall expire in two (2) years from the date of issue in accordance with Section 51.04 (a) of the Board’s regulations if the work authorized by the permit is not completed within two years of the date the permit was issued. 2 C. Plan of onsite System or Subsurface sewage Disposal System, or Systems. The submitted plan must show as a minimum: the lot to be served, location and dimensions of the system (including reserve area), design calculations, existing and proposed contours at one or two foot intervals, location and log of deep observation holes, locations and results of percolation tests, location of any streams, surface and subsurface drains and wetland resource areas within 100 feet of the system, known sources of water supply within 200 feet of the system, location of any proposed well to serve the lot, location of water lines on the property, depth to ground water/maximum ground water elevation in the area of the soil absorption system, and a profile of the system. The plan must be prepared, reviewed and stamped, by a professional engineer, or a registered sanitarian and stamped by a licensed professional land surveyor as required. D. Use The use of an individual system shall be in compliance with the terms of the permit issued therefore and shall not exceed the design capacity of the system. Design capacity shall not be reduced for seasonal use. E. Building or Plumbing Permits/Subdivision Plans. No Building Permit, foundation permit, special building permit or plumbing permit shall be issued until a Disposal Works Construction Permit has been first obtained, unless the Board of Health determines that the existing system is adequate for a proposed alteration or addition to an existing dwelling. F. Certificate of Compliance. A new individual system and alteration and repairs to an existing individual system shall not be placed in service, nor shall new dwellings or buildings or additions thereto, which must rely on new individual systems for sewage disposal; be occupied until the Board of Health has issued a Certificate of Compliance indicating that said system has been located, constructed, altered, or repaired in compliance with the terms of the permit and the requirements of this regulation. The Board shall require inspection of all construction by a professional engineer or a registered sanitarian and the agent of the Board of Health; and require certification in writing that all work has been completed in accordance with the terms of the permit and 3 the approved plans. Such certification shall include an As-Built plan stamped by the licensed professional engineer or registered sanitarian and stamped by a professional land surveyor as required. G. Fees. Fees for the issuance of a construction permit, issuance of a Certificate of Compliance, and test pit/percolation test observation shall be charged by the Board of Health at the time an application is made, and shall be in accordance with the fee schedule adopted by the Board of Health. H. Conditions for Permit Issuance. In addition to the obligation to meet the general requirements above, and those set forth in Title Five of the State Environmental Code hereby incorporated by reference, no certificate of compliance and no permit for the construction of an individual system shall be granted unless the additional standards set forth in sections 64.02 through 64.06 and all other applicable Town of Nantucket Board of Health Regulations are met. 64.02 DETERMINATION OF MAXIMUM GROUND WATER ELEVATION- DEPTH TO GROUNDWATER. A. On any lot there will be at least two deep observation holes in the area to be used for leaching plus any additional number of deep observation holes which in the opinion of the Health Agent will be necessary to determine the consistency (or lack thereof) of the character of the soil. The observation holes shall be examined to a depth of at least 6 feet below the bottom of the proposed leach facility, but in no case shallower than 10 feet total depth, unless this depth is unattainable because of existing site conditions as determined by an agent for the Board. Ground water elevations/depth to groundwater shall be determined as set forth in Board of Health Regulation 50.00. B. All deep observation holes shall be witnessed by the Board of Health or its designated agent. C. Maximum groundwater elevation/depth to groundwater shall be determined for all soil absorption system (SAS) repairs, expansions and/or new construction of onsite sewage disposal systems. 4 64.03 LOCATION OF SOILS ABSORPTION SYSTEMS. A. All soil absorption systems located in non Nitrogen Sensitive areas shall be designed and located so that at least five (5) feet of naturally occurring pervious material remains below the bottom of the system. The bottom of the system shall be constructed at least five (5) above maximum ground water elevation /depth to ground water (Town of Nantucket Board of Health Regulations 50.00 Definitions) as determined by soils tests conducted by a Certified Soil Evaluator and witnessed by an Agent for the Board of Health. Soil absorption systems shall be located in accordance with the Town of Nantucket Board of Health Regulation 64.04 B. All soil absorption systems located within a Nitrogen Sensitive area that incorporate Innovative/Alternative technologies with enhanced nitrogen/phosphorous removal shall be designed and located so that at least five (5) feet of naturally occurring pervious material remains below the bottom of the system. The bottom of the system shall be constructed at least five (5) feet above maximum ground water elevation/depth to ground water (Town of Nantucket Board of Health Regulation 50.00 Definitions) as determined by soils tests conducted by a Certified Soils Evaluator and witnessed by an Agent for the Board of Health. Soils absorption systems shall be located in accordance with the Town of Nantucket Board of Health Regulations 64.04. C. All soil absorption systems located in Nitrogen Sensitive areas shall be designed and located so that at least six (6) feet of naturally occurring pervious material remains below the bottom of the system. The bottom of the system shall be constructed at least six (6) feet above maximum ground water elevation/depth to ground water (Town of Nantucket Board of Health Regulations 50.00 Definitions) as determined by soil tests conducted by a Certified Soils Evaluator and witnessed by an Agent for the Board of health. Soil absorption systems shall be located in accordance with the Town of Nantucket Board of health regulations 64.04 D. Repair/upgrades of existing failed on site sewage disposal absorption systems that service existing structure, where no addition of habitable space is proposed, shall be designed to incorporate innovative/alternative technologies with enhanced nutrient removal and constructed to meet the minimum separation of five (5) feet above 5 maximum ground water elevation/depth to ground water (Town of Nantucket BOH Regulations 50.00 Definitions) as determined by soils tests conducted by a Certified Soil Evaluator and witnessed by an agent for the Board of Health. Soil absorption systems shall be located in accordance with the Town of Nantucket Board of Health regulations 64.04. E. No system shall be permitted within coastal wetlands resource areas, including but not limited to coastal wetlands as defined in Chapter 136 of the Nantucket Code and regulations adopted there-under, except as provided in 64.03C F. No system shall be permitted within the V or VE zones shown on the “FEMA Maps” for the Town of Nantucket. Systems approved by the Board or it’s designated agent may be constructed within other special flood hazard areas 100-Year flood zones) if designed to minimize the release of contaminants from the disposal system into the flood waters. Disposal systems in these areas shall include the following features: 1. Vents shall extend at least 1 foot above the 100 year flood elevation. 2. Access ports for all components of the system shall be watertight and shall either have bolted lids or shall extend above the level of the 100 year flood. 3. Where sewage or effluent pumping is necessary, electrical switching shall be provided to prevent to the pumps from operating during periods of inundation. 4. No plumbing fixtures below the 100 year flood elevation shall be connected to the disposal system except by means of an ejector pump connected to the gravity waste plumbing of the structure at a point above the flood level. 64.04 PERFORMANCE STANDARDS FOR LEACHING FACILITIES A. No soils absorption system shall be installed within 300 feet of any designated Nantucket Nitrogen, Phosphorous and/or Pathogen Sensitive Area (Board Regulations 50.00). 6 B. Nitrogen Loading Limitations: 1. No system serving new construction in nitrogen sensitive areas as defined in Regulation 50.00 shall be designed to receive or shall receive more than 110 gallons of design flow per day per 10,000 square feet of lot area. 2. No system serving new construction in areas where the use of both on-site systems and drinking water supply wells is proposed to serve the facility may be designed to receive or may receive more than 110 gallons of design flow per day per 10,000 square feet of lot area from residential uses provided that any cumulative flow exceeding 330 gallons of design flow per day demonstrates a minimum 25% TN effluent reduction. C. Phosphorous loading limitations: 1. No system serving new construction in nitrogen sensitive areas shall be designed to received or shall receive more than 440 gallons of design flow per day per acre. 2. All on-site leaching facilities for new construction and repairs/upgrades shall be located a minimum of 300 feet from the edge of the down gradient surface water body, unless documented that water recharge beneath subject on-site system is not directed to the adjacent surface water body. All on-site system leaching facilities for repairs/upgrades shall be located a minimum 300 feet from the edge of the down gradient freshwater surface water body or demonstrate maximum feasible compliance. D. Pathogen Loading Limitations. E. System Weight Loading Criteria. 1. All such systems shall be installed to withstand H-20 Wheel Loading. 64.05 SEPTIC SYSTEM ACCESS. A. A minimum of one access hole and one inspection hole and cover for septic tanks and leach pits shall be provided and brought to grade for new construction. Access and covers for any pump chambers shall be at grade. 7 B. Access and inspection hole covers must be a minimum diameter of eighteen (18) inches. The cast iron ring and cover must be of medium or heavier duty weight and must withstand a minimum of H- 20 wheel loading. 64.06 RELIEF PROCEDURES. A. Any lot referred to in a deed or shown on a plan duly recorded at the Nantucket Registry of Deeds or filed in the land registration office before the effective date of this regulation August 31, 1990 shall comply with Sections 64.03 A and 64.04 of this regulation to obtain maximum feasible compliance, meaning that soil absorption systems shall be located as close to the regulation distance requirements as lot size allows. B. In the event that a pre-existing lot cannot comply with the 300 foot horizontal set back requirement set forth in Section 64.04 A and/or the six (6) foot separation requirement set forth in section 64.03 A of these regulations, then , in that event, the Board may, in it’s sole discretion grant to said lot an exemption from said requirements upon the following conditions: B.1. The applicant shall submit to the agent of the Board of Health a design plan stamped by a licensed professional engineer, registered sanitarian, and licensed professional land surveyor as required, showing the location of the proposed soils absorption system on said lot, the location of all wells, soils absorption systems and water bodies within 300 feet of said soils absorption system, or as far from said locus as deemed necessary to determine that compliance with this section cannot be met, and the groundwater gradient and direction of flow for said lot (as determined by use of Horsley Whitten & Heggimin Report of March 1990 on file with the Board of Health, the United States Geologic Survey Map HA 615, or more detailed map duly adopted by the Board at a Public Hearing. B.2. For pre-existing vacant lots held in contiguous ownership prior to the effective date of this regulation, August 31, 1990, the applicant shall also file a stamped plan with such design and location information showing maximum feasible compliance with the 300 foot down gradient set back requirements and/or 6 foot vertical separation from ground water requirement for contiguous lots abutting the subject lot. 8 B.3. Failed soil absorption systems on an improved lot shall, if necessary, be relocated on said lot at the time said soils absorption systems are replaced to the maximum set back distances attainable up to 300 feet and/or maximum vertical separation distance attainable up to 6 feet with incorporation of I/A (innovative/alternative) technology. B.4. Adjustments to pre-existing lot lines shall not subject said lot to compliance with the 300 foot setback requirements on the condition that such adjustments do not create an additional “buildable” lot and the distance between the soils absorption system on said lot and water body is not diminished. B.5 In addition to these requirements, on site systems constructed within the 100 year flood zone as shown on the current FEMA map shall be subject to the engineering design requirements for “mounded” systems as set forth in Section 64.03 A of this regulation. C The applicant may design a system using design flows for a smaller number of bedrooms than are presumed in this definition by granting to the approving authority, a deed restriction limiting the number of bedrooms to the smaller number. 64.07 SPECIAL VARIANCE. A. The Board of Health, in its sole discretion. May issue a variance from the strict application of these regulations to any particular case in accordance with its procedures and its regulations set forth below. B. Prior to granting a variance from its regulations, the Board of Health shall conduct a hearing to consider granting a variance from the strict application of its regulations. The Board of Health may grant a variance, with or without conditions, upon its finding that : 1. the person requesting the variance has established that enforcement of the provisions of these Regulations from which a variance is sought would be manifestly unjust, considering all the relevant facts and circumstances of the individual case; and 2. The person requesting a variance has established that a level of environmental protection that is at least equivalent to that provided under these Regulations can be achieved without strict application of the provision of these Regulations from which a variance is sought. 9 B. Pursuant to its regulations and other applicable law, The Board of Health shall enact rules and regulations pertaining to its hearings and its review hereunder. Said rules and regulations shall be known as the “Nantucket Board of Health Special Variance Regulations”, and shall be on file with the Town Clerk of the Town of Nantucket. 64.08 ENFORCEMENT Without limiting any other available remedies or penalties, the Board of Health may punish any person or entity that violates these regulations by assessing a penalty of $300.00. Each day or part thereof during which such violation occurs or continues shall constitute a separate offense. As an alternative to criminal prosecution or civil action, the non-criminal disposition procedure set forth in M.G.L. c40, Section 21D, and Sections 1-2,-1-3,1-4,1-5, and 1-6 of the Code of the Town of Nantucket may be used with 5 and 1-6 of the Code of the Town of Nantucket may be used with a penalty of $300.00 for each violation, each day or part thereof during which such violation occurs or continues constituting a separate offense. Approved: December 1, 2004 __________________________ Whitey Willeaur – Chairman __________________________ Brian Chadwick __________________________ Michael Kopko __________________________ Michael Glowacki __________________________ Douglas Bennett Effective date: January 1, 2005 Amended: June 14, 2006 10 TOWN OF NANTUCKET BOARD OF HEALTH UPGRADING OF SUBSTANDARD ON-SITE SEWAGE DISPOSAL SYSTEMS LOCAL REGULATIONS 66.00 66.00 upgrading of substandard on site sewage disposal systems. A. purpose. These regulations are intended to protect the public health and general welfare by ensuring the upgrading of substandard sewage disposal systems in a manner which will protect the quality of the ground water on the Island of Nantucket. B. Authority. These regulations are adopted by the town of Nantucket’s Board of Health as authorized by Massachusetts general Laws, Chapter 111, Section 31. 66.01 Compliance requirements . A. Systems of domestic sewage disposal which do not presently comply with the minimum standards specified by the state and local regulations shall be brought in to compliance when: A.1 An application for a building permit for which expansion of the existing system is required is filed with the proper departments. The soil absorption system shall comply with the maximum separation and/or set back distance attainable up to 300 feet without the use of a lift pump. A.2 Any property transfer, not exempt, takes place. Exempt property transfers are defined in section 66.03 B. 66.02 Compliance standards. A. All subject systems shall comply with the minimum standards of the 1978 State Sanitary Code, and with current local regulations to the maximum extent possible, meaning that systems shall be located as close to the horizontal separation distance requirements as lot contours and size allow unless the attainable increase in required horizontal separation distance is 20 feet or less. Systems which can not meet 1978 Title Five standards shall require a variance (sec. 67.06). B. Prior to selling, conveying, or transferring title to real property in Nantucket which contains an existing system, the owner thereof shall have had an inspection of said system by a system inspector certified by the State, indicating that said system is functioning, non- functioning, or in failed condition. C. The inspection shall take place not more than 270 days prior to, or 180 days after the transfer of property. The Agent of the Board of Health must receive the signed official inspection form and/or Certificate of Compliance within seven (7) days of the inspection. 66.03 EXEMPTIONS. A. The systems described in the following paragraphs shall be exempt from this upgrade regulation to the extent therein provided. A.1 Any system complying with the 1978 State Sanitary Code as evidenced by an “as-built” plan on file with the Nantucket Board of Health which permit is dated less than three (3) years from the date of transfer and has proof of annual pumping shall be exempt from this compliance standard and no inspection of the system shall be required. A.2 Any system which complies with the 1978 State Sanitary Code as evidenced by an “as-built” plan on file with the Nantucket Board of Health which has been inspected less than three (3) years from date of transfer and has proof of annual pumping shall be exempt from these compliance standards and no inspection of the system shall be required. B. Any transfer of real-estate which qualifies for a (b) through (l) exemption, inclusive, from the Nantucket Island Land Bank fee imposed by Chapter 669 of the acts of 1983 of the Commonwealth of Massachusetts, as amended, as more specifically set forth in Section 12 of such Act, as amended shall also be exempt from these upgrade upon transfer compliance requirements unless said transfer is to a third party for fair market, monetary consideration. C. Whenever a person has submitted a subdivision, or preliminary subdivision plan followed within 7 months by a definitive plan, or a plan referred to in M.G.L. Chapter 41, Section 81P as the case may be, the land shown on such plan shall be governed by the provisions of the State Environmental Code and Board of Health Regulations, if any, which differ from the health codes which are in effect at the time of first submission of the plan. Such provisions shall apply while the plan is processed until rejected, or if approved, until three (3) years from the date of filing pursuant to M.G.L. Chapter 111 Section 127P. D. Notwithstanding the general effective date of these regulations in section 67.08, the effective date of this upgrade upon transfer requirement (Section 66.01 A. 2 et. Sec.) shall be February 1, 1991. 1 TOWN OF NANTUCKET BOARD OF HEALTH REGULATIONS : INSPECTION AND UPGRADING OF SUBSTANDARD ONSITE SEWAGE DISPOSAL SYSTEMS WITHIN THE NANTUCKET HARBOR WATERSHED PROTECTION DISTRICT LOCAL REGULATIONS 68.00 68.00 INSPECTION AND UPGRADING OF ON-SITE SEWAGE DISPOSAL SYSTEMS. A. Purpose. Whereas the Nantucket Harbor Study of March 1997, as completed by the Woods Hole Oceanographic Institution, denotes increasing levels of nutrient loading in Nantucket Harbor, these Regulations are promulgated to further limit said nutrient loading and other sources of contamination and to protect and enhance the quality of ground water flowing into and affecting Nantucket’s harbor waters. B. Authority. These Regulations are adopted by the Town of Nantucket’s Board of Health as authorized by Massachusetts General Laws, Chapter 111, Section 31. 68.01 Definition. A. NANTUCKET HARBOR WATERSHED – The area constituting the watershed for Nantucket Harbor, as described in a technical report entitled “Nantucket Water Resource Management Plan,” 1990, by Horsley Witten Hegemann, Inc., and as delineated 2 on a map entitled “Nantucket Harbor Watershed,” Nantucket GIS, dated January, 1999. 68.02 Compliance Requirements. A. Properties utilizing in-ground soil absorption systems located within Zone A of the Nantucket Harbor Water- shed District as established by these Regulations and as demonstrated on a map entitled Nantucket Harbor Watershed District with 1000 foot Buffer Belt, shall have the existing soil absorption system inspected by a Massachusetts licensed system inspector within 30 months of promulgation of these Regulations. Said Inspection Report shall be recorded with the Nantucket Health Department within 21 days of the completed inspection. B. Properties utilizing in-ground soil absorption systems located within Zone B of the Nantucket Harbor Water- shed District as established by these Regulations and as demonstrated on a map entitled Nantucket Harbor Watershed District with 1000 foot Buffer Belt, shall have the existing soil absorption system inspected by a Massachusetts licensed system inspector within 36 months of promulgation of these Regulations. Said Inspection Report shall be recorded with the Nantucket Health Department within 21 days of the completed inspection. 68.03 Inspections. A. All systems shall be inspected to determine the presence and/or absence of hydraulic failure and depth to ground water. Depth to ground water shall be determined by direct observation of highest ground water elevation (including seasonal perched and tidally influenced ground water) in a test pit 3 excavation, unless an alternative method for accurately determining the depth to ground water has been approved in writing by the Health Director. B. The Health Director may, based on existing unique development conditions or due to the proximity of multiple systems within a limited geographic area, substitute a pre-approved ground water monitoring protocol for the test pit excavation. The monitoring protocol shall require as a minimum; - data collected over a 12 month period - a minimum of 3 wells offset to define ground water flow direction as well as depth. 68.04 Repairs to failed systems. A. The owner of a system meeting hydraulic failure criteria pursuant to these Regulations as stated on the Town of Nantucket Board of Health Septic System Inspection Report/Certificate of Compliance Form shall bring the system into compliance with all applicable state and local regulations within 30 days of the date of inspection. B. The owner of a system meeting failure criteria, exclusive of hydraulic failure, pursuant to these Regulations as stated on the Town of Nantucket Board of Health Septic System Inspection Report/Certificate of Compliance Form shall bring The system into compliance with all state and local regulations within 18 month of the adoption of the Assessment Report as required in 68.05 B and/or within 30 months of the expiration date of 4 Zone A and B inspections, subject to 68.05C 68.05 INSPECTION EVALUATION PERIOD A. Within three months of the inspection date of Zone A and B inspections, the Health Department shall tabulate and publish the inspection results. B. Within six months of the expiration date of Zone A and Zone B inspections, the Health Department shall provide a preliminary assessment report to the Board of Health. This report shall include a brief evaluation of treatment options to effectuate implementation of best available engineering design for all required repairs/upgrades. C. No later than six months after the expiration date of Zone B inspections, the Board of Health shall adopt the Nantucket/Madaket Assessment report, including recommendations. 68.06 Exemptions. A. Properties whose on site sewage disposal design is documented to be based on test pits and percolation testing observed by the Board of Health after November 1, 2003. B. Properties which have been inspected and have both a Town of Nantucket Board of Health Septic System Inspection Report and a Certificate Of Compliance Form filed with the Nantucket Health Department and dated within 24 months before promulgation of these Regulations are exempt from inspection and compliance standards as set forth in these Regulations. 5 C. In all areas where Town of Nantucket mapping shows that the separation between the bottom of the soil absorption system and the predicted ground water elevation (based on HWH study and/or USGS Hydrologic Investigation Atlas Water resources Map dated 1980) exceeds ten (10) feet, testing will not be required. 68.07 Enforcement. A. Enforcement of these Local Regulations shall be effected through Town of Nantucket Board of Health Local Regulations 67.00 Miscellaneous Provisions. B. These Regulations and the amendments thereto shall become effective upon the date of publication. Nantucket Board of Health ____________________________ Whitey Willauer- Chairman ____________________________ Patricia Roggeveen ____________________________ Brian Chadwick ____________________________ Michael Kopko ____________________________ Allen Reinhard Date Published September 29,2005 Date Amended June 14, 2006 Date Amended November 28, 2007 End of inspection period Zone A – December 14 2008 End of inspection period Zone B - June 14 2009 TOWN OF NANTUCKET SEPTAGE MANAGEMENT PLAN ADOPTED 11-9-05 BY BOARD OF SELECTMEN INTRODUCTION Long term protection of Nantucket’s quality of life depends on the Town’s ability to prevent adverse impacts to human and environmental health. Successful management of the treatment and disposal of human waste and wastewater is the single most important factor in achieving long term protection for Nantucket’s ground and surface water resources. Sustaining high quality ground and surface water resources is absolutely necessary to protect human health, to maintain healthy environmental resources, the economy and the quality of life expected by residents of and visitors to our island. Management of the treatment and disposal of human waste and wastewater on Nantucket involves direct management and regulation of flows carried to treatment plant facilities and of flows disposed of through onsite sewage disposal facilities. Currently the Town of Nantucket is in the process of constructing and upgrading treatment facilities in Siasconset and Surfside in accordance with approvals from the Massachusetts Department of Environmental Protection (DEP) and as authorized by Town Meeting. The goal of this Septage Management Plan (SMP) is provide the tools, options and resources necessary for Nantucket to manage onsite wastewater management systems so as to protect and maintain public health, ensure the protection of ground and surface water quality, maintain water resources as environmental, economic, recreational and aesthetic assets, retain local control of onsite wastewater disposal systems without regulatory or management intervention, to protect investments with respect to property values, to maximize options for onsite management based on implementation of best available management practices tailored to local conditions and in compliance with state and local regulatory requirements and to identify man power and financial needs . The successful long-term sustainability of onsite wastewater disposal systems is dependent upon proper design, operation and maintenance in order to prevent adverse health and environmental impacts. This SMP is intended to operate in conjunction with the Town’s municipal wastewater collection systems. It should be noted here however, that depending on future management and design implementation options that may become available through currently proposed changes to DEP Title 5, the implementation of the SMP may result in flow quantity and strength changes discharged to the Town’s wastewater treatment facilities that may require future retooling of plant processing practices. GENERAL In the late 1990’s, the Town of Nantucket initiated two distinct processes to address the protection of its ground and surface water resources. First, in 1997, Town Meeting authorized a study with resultant recommendations for protecting the Nantucket Harbor Watershed with the intent that the efforts of the Nantucket Harbor Watershed Work Group would result in the evaluation of existing data to determine and rank sources of pollutants. This Work Group completed their review of existing data and produced a report that ranked pollutant sources, prioritized local regulatory actions that has resulted in the implementation of Board of Health regulations for the Nantucket Harbor Watershed, sponsored educational forums for professionals, regulators and landowners, and established by its example, the prototype for a public participation process and action template for the Madaket Harbor Watershed Planning Group and future defined needs areas across the island. Second, in 1998, the Town of Nantucket authorized an Island- wide Comprehensive Management Plan/Environmental Impact Report to address the wastewater needs of the Island. A large component of the CWMP was to identify those areas on the Island, based on available local file information and available mapping information, that cannot sustain onsite wastewater disposal systems and those areas that can sustain long term use of onsite wastewater disposal systems under the guidance of a SMP. The SMP is intended to provide a comprehensive management program that encompasses the design, construction, inspection, maintenance, monitoring, disposal and treatment of septage, record keeping, public outreach and education, regulatory changes, identification of financial sources and options to fund implementation, define personnel needs and outline SMP compatibility with existing and proposed improvements to existing municipal treatment plan facilities. The SMP as currently proposed recognizes the actions already taken by the Board of Health since 2003 and presumes that the SMP will be administered by the Board of Health and implemented through the Health Department. Further, the SMP recognizes the uncertainties of the Commonwealth’s Massachusetts Estuaries Program and proposed changes to DEP’s Title 5 Regulations and maximizes locally generated data from actual onsite observations and inspections as the basis for ongoing and future management actions. BENEFITS Benefits of the SMP accrue to the Town of Nantucket, individual property owners, residents and visitors to the island. This SMP will serve to protect the public health and minimize adverse environmental impacts. This SMP will offer an opportunity to obtain the same level of service for onsite sewage disposal systems as the areas on Island serviced by the municipal sewer and treatment plant system. Specific benefits of this SMP include: -protection of ground and surface water quality (elimination of failed systems, potential elimination of black water contaminants, reduction of pollutant loading source, regulatory changes tailored to existing conditions and documented sensitive areas) -protection of public health (elimination of failed systems) -ground water conservation and more effective watershed based recharge (repair and upgrades in place will allow for infiltration of “treated effluent” which will recharge groundwater within watershed it is generated rather than as a transfer to municipal plant facilities in a different watershed) tax rate equity for financing of municipal costs for treatment plant upgrades and operation and maintenance (black water pump out/discharge available to all with transport to/treatment at plant) -cost savings to property owner for long term operation and maintenance of onsite systems (fewer failures and repairs, co- ordination of inspection/monitoring requirements, etc.) -funding assistance options to owners for repair and town for management -education and outreach to targeted recipients to maximize effectiveness -ability to develop effective enforcement policies, practices and penalties -Board of Health/Health Department implementation maximizes public exposure and outreach opportunities and allows for variance procedure as deemed necessary STANDARDS The SMP is designed to work in conjunction with the Town’s municipal wastewater system and with state and local standards for inspection, design, construction, repair, monitoring and record keeping of onsite systems as referenced below. -310CMR15.00 (Title 5, including proposed revisions relative to blackwater/graywater separation, holding tanks, etc.) -TON Board of Health Regulations Sections 50.00, 51.00, 60.00, 61.00, 62.00, 64.00, 66.00, and 68.00 as most recently revised in 5/05 -TON Chapter 99, Nantucket Harbor Watershed -TON Bylaws -Massachusetts DEP TMDL Program, Massachusetts Estuaries Project TOWN OF NANTUCKET SEPTAGE MANAGEMENT PLAN COMPONENTS The primary elements/components of the Nantucket Septage Management Plan are as follows: 1)Regulations (including variance provisions and escrow options) 2)Inspections (Nantucket Harbor Watershed, other identified needs areas/environmentally sensitive areas, Island wide) 3)Staffing (Health Department analysis; consultant staffing options) 4)Funding Options (Homeowner assistance; Town facilities & management- User fees &/or tax base) 5)Record Keeping (inspections, monitoring, tracking) 6)Education and Outreach (Nantucket Harbor Watershed, other identified needs areas/environmentally sensitive areas, Island wide) 7)Management of Onsite Sewage Disposal Systems (Nantucket Harbor Watershed, other identified needs areas/environmentally sensitive areas, Island wide) 8) Timeline Since 2003, when Earth Tech provided its Draft Septage Management Plan for Nantucket, local regulatory boards, commissions and advisory committees have worked to revise and/or implement regulations, update inspection standards, develop education and outreach materials and strategies, investigate funding options and determine staffing options and needs for septage management. In each instance the Board of Health and Health Department has taken the lead in implementing septage management actions for the Island based on actual existing conditions and/or Island based studies. The following table summarizes actions taken to date and lists actions identified for future action. MILESTONE/ACTION/PLAN COMPONENT TARGET DATE/TIMELINE 1)REGULATIONS: Local: A.Update & implement Nantucket adopted 5/05 Harbor Watershed (NHW) regulations 1.include variance process, enforcement procedures, inspection & certification schedules 2. develop repair options proposed 8/05 (escrow account) 3. adopt blackwater separation anticipated 6/06 separation options B. Adopt & implement Madaket Harbor anticipated 12/05 Watershed (MHW) regulations, using NHW regs as template C. Identify remaining “needs areas/anticipated fall 2006 environmentally sensitive areas” D. Adopt & implement regulations, using anticipated 1/07 – 12/07 NHW regs as template, for remaining identified “needs areas/environmentally sensitive areas” State: A.Title 5 changes 1. actively participate as advocate 5/05 – 7/06 for blackwater separation 2. actively participate as advocate 5/05 – 7/06 for holding tank and “environ- mentally sensitive areas” changes B. Massachusetts Estuaries Program 1/03 to post 1. assist with program designation hearings 2. stay informed to maximize benefit to town 2. INSPECTIONS (record keeping, funding and staffing listed separately) A. Revise inspection and certification standards 5/05 B.Revise inspection schedules 1. Nantucket Harbor Watershed 5/05 2. Madaket Harbor Watershed anticipated 12/05 3. other identified “needs areas/ 1/07 – 12/07 environmentally sensitive areas” 4. other island areas: real estate no changes currently transfers, failed systems anticipated 3. STAFFING A. Develop staffing cost needs analysis 4/05 for implementation of NHW regs and revised inspection/certification standards B. Implement staffing assignments for 9/05 – 10/05 for NHW regulations, inspections & certifications C.Seek additional staff support 1. food service, housing 5/05 – 12/05 inspections 2. consultant assistance for as deemed necessary for septic by separate contract D. Develop staffing cost and needs analysis 11/05 for implementation of Madaket Harbor Watershed regs, inspections, certifications E. Implement staffing assignments for 1/06 – 3/06 MHW regulations, inspections, Certifications F.Seek additional staff support 1. consultant assistance for septic as deemed necessary by separate contract 2. additional personnel for 3/06 for Health Department G. Develop staffing cost & needs analysis 12/06 for implementation of regulations for other identified “needs areas/environ- mentally sensitive areas”, inspections certifications H. Implement staffing assignments for other 1/07 – 3/07 identified “needs areas/environmentally sensitive areas”, inspections, certifications I.Seek additional staff support 1. consultant assistance for septic as deemed necessary by separate contract 2. additional personnel for 3/07 Health Department 4. FUNDING A.Town Wide 1.user fees - to offset non-septic inspections (cover shift in personnel work assignment); to cover additional staffing costs for septic work, including field work, reports & record keeping; and cover costs of consultant services a. develop cost analysis for increase preliminary assessment in Health Department staff, 4/05 for consultant services and/or combination of both b. establish user fee schedule 9/05 c. establish revolving account done 2.tax base – for O&M, retooling and capital cost offsets fro treatment plant facilities a. develop cost analysis for done ? regular septic system maintenance schedule use of treatment plant b. develop cost analysis for 7/06 blackwater treatment (retooling, etc) 3. grants ongoing B.Onsite septic system owner 1. research available loan 10/05 programs 2. establish necessary protocols, 1/06 agreements, infrastructure for loan programs a.Nantucket b.co-operative with Barnstable County 5. RECORD KEEPING A.Board of Health – establish clerical prelim computer accounting system for inspections, accounting program Compliance, scheduling, tracking in place, update as Needed, ongoing B.Board of Health – system performance Monitoring 1. Town of Nantucket based ongoing 2. co-operative with Barnstable to be negotiated but County available – 9/05 3. private maintenance contracts ongoing based on need C.Financial Accounting 1. Health Department option ongoing system to be expanded as implementation needs require 2.TON Accounting Dept option 1/06 if deemed viable 6. EDUCATION & OUTREACH A.Nantucket Harbor Watershed 1.Nantucket Harbor Watershed Work Group a.public informational 1998- 2002 meetings held b. public workshops held 2002 c. reports issued 2002 d.information posters & 2000-2002 pamphlets developed & distributed 2.Health Department a. participation in civic 2004 group meetings b development & 2004 distribution of NHW regulations/compliance explanation c. development &10/05 distribution NHW informational notice of regs and noncompliance consequences d. development &3/06 distribution of warning notice for noncompliance to NHW regs B.Madaket Harbor Watershed 1. Madaket Harbor Watershed Work Group a. public informational meetings 10/05 – 12/06 b. development of outreach materials using NHW efforts as template 2. Health Department a. same actions/items as listed 10/05 – 12/06 for NHW, tailored to Madaket C. Other identified “needs areas/ environmentally sensitive areas” 1.Dependent upon area identified 12/06 – 12/07+ but will use information developed for NHW and MHW as template D.Town wide 1.Board of Health 2003- ongoing 2.Town Meetings 1997-2004 3.Other public meetings/hearings ongoing of boards, commissions, committees 7. MANAGEMENT OF ONSITE SEWAGE DISPOSAL SYSTEMS A.Nantucket Harbor Watershed 1.Board of Health/Health Department a. establish tracking system 2004 b. establish inspection schedule 10/05 c. establish maintenance pumping 2/06 schedule d.evaluate & determine whether 10/5 onsite O & M plans will be established by BOH/Health Department; private sector Contractual agreements; Guidelines provided from Other sources (i.e. Barnstable County Health Dept.) e. evaluate & determine need for 10/05 & ongoing consultant contractual agreement to provide assistance f. determine user fee schedule to 10/05 & ongoing offset costs to TON 2.Onsite sewage disposal system owner/manager a.professional O & M contract 10/05 required B.Madaket Harbor Watershed 1.Board of Health/Health 12/05 Department – same as for NHW, tailored to MHW 2. Onsite sewage disposal system 12/05 owner/manager – same as for NHW, tailored to MHW C.Other identified “needs areas/ environmentally sensitive areas” 1. Board of Health/Health 12/06 Department – same as for NHW & MHW, tailored to needs areas 2. Onsite sewage disposal system 12/06 owner/manager – same as for NHW & MHW, tailored to Needs areas D. Island wide 1. Board of Health/Health Department a.establish maintenance 6/06 pumping and inspection schedule b.require O & M Plan and 10/05 contract for all I/A systems c.establish tracking system 2004 d.establish user fee schedule 10/05 & ongoing 8. TIMELIINE; (reference attached graph) The timeline for the SMP as currently proposed is extremely aggressive and will be impacted both by state and local actions. However, it is clear that the basic components of the SMP can be implemented locally within the existing framework of Town and County of Nantucket government structure. It is also clear that implementation of the SMP as proposed will require strong administrative and financial commitment from governmental officials and voters, not only to achieve the goals as set forth but to have a chance at meeting the proposed schedule. The costs to implement this SMP will be significant but the rewards to the community and the island will be more than quadruple the dollars and time spent. DISREGUARD AS FIRST DRAFT ATTEMPT----CHOSE DIFFERENT FORMAT CURRENT STATUS OF SEPTIC MANAGEMENT PLAN COMPONENTS 1. REGULATIONS: During the last two years, the Nantucket Board of Health has adopted regulations strengthening the management of onsite sewage disposal systems within the Nantucket Harbor Watershed and the Island in general. It is anticipated that the Board of Health will adopt regulations for the Madaket Harbor Watershed by the end of 2005 and determine future “needs areas/environmentally sensitive areas” by 2007. The Conservation Commission has revised its regulatory performance standards to require a 100 foot set back for septic A. LOCAL - Board of Health 1.Nantucket Harbor Watershed (updated 5/05) -includes variance provisions, mandatory inspection schedule, mandatory repair schedule and enforcement (updated 5/05) -proposed “escrow” option to be presented 8/05 -intended to serve as template for Madaket Harbor Watershed and other to be designated “needs areas/environmentally sensitive areas” 2.Septic System Design and Inspections (updated 5/05) -standards applied to all areas of island -Nantucket Harbor Watershed establishes mandatory inspection schedule and may require enhanced treatment design -Madaket Harbor Watershed regulations establishing mandatory inspection schedule and enhanced treatment provisions anticipated for adoption in 12/05 -Regulations for other “needs areas/environmentally sensitive areas” as documented by existing conditions data or required by DEP TMDL’s is targeted for 1/07 Other Local Regulatory Agencies/Boards/Commissions (as deemed appropriate) 1.Planning Board – consideration of communal space dedicated for “subdivision septic system design” with association required O & M and monitoring may be warranted in environmentally sensitive areas. 2.Conservation Commission – currently requires all leaching facilities to be in excess of 100 feet from all wetland resource areas. If waiver granted, septic design most likely to require enhanced treatment. 3.Department of Public Works – consideration of existing sewer hook up requirements and blackwater holding tank discharge impacts will be necessary B. STATE 1.DEP Title 5 2.DEP Groundwater Discharge Permit (POWTF) Nantucket, MA (project #225139)Woodard & Curran CWMP Update September 2014 APPENDIX F: WASTEWATER DATA FLOWS AND LOADS CALCULATIONS 980 Washington Street | Suite 325 Dedham, Massachusetts 02026 www.woodardcurran.com T 800.446.5518 T 781.251.0200 F 781.251.0847 MEMORANDUM TO:File FROM: DATE:March 20, 2013 RE:Nantucket CWMP – Flows and Loads This memorandum presents the methodology for estimating wastewater flows and loads for the CWMP Update. In order to update the assessment of the Town’s wastewater disposal needs and recommend appropriate wastewater disposal solutions for each Need Area and Study Area, Woodard & Curran estimated the wastewater flows and waste loads that would likely be generated in these Areas. W&C updated the flows and loads for the Need and Study Areas by first revising the counts of developed and undeveloped residential and commercial parcels in each Area, and verifying zoning and land use for each parcel using the Town’s Assessor’s Database, State Land Use Codes, and the Town’s Zoning mapping in GIS. All developed single-family residential parcels were assumed to have at least one wastewater connection. All developable or potentially developable residential parcels that met zoning were assumed to have at least one wastewater connection. We assumed any parcel that meets zoning could have a second dwelling. For example, single-family residential parcels that met zoning were assumed to have two wastewater connections. However, based on discussions with the Town Planner and the fact that approximately only 12% of residences on the island currently have second dwellings, therefore to be conservative, overall, we assumed only 25% of the second dwellings would be built. All developed commercial parcels were assigned a flow based on acreage. Developable and potentially developable commercial parcels that met zoning were also assigned a wastewater flow based on acreage. Based on discussions with Nantucket Assessor, we assumed all multi-family parcels in the Areas are equal to two residential wastewater connections. Average Daily Flow estimates for both summer and winter were developed using the above described parcel count methods and applying the unit flows consistent with the previous CWMP work. In the Phase I CWMP, wastewater flows from 1999 at the Surfside Wastewater Treatment Facility were analyzed in conjunction with the number of residential and commercial units connected to the system to estimate unit wastewater flows. Population data were used to determine the average number of people per residential household. Table XX presents the results of this analysis from the Phase I CWMP. These values were used in calculations for this CWMP update. 2013.03.25 CWMP Flows And Loads Memo Error! Reference source not found. Season Residential Wastewater Flow (GPD) Average Number of People per Household Gallons per Capita Per Day Commercial Wastewater Flow (GPD) Summer (June – September) 320 4.5 71.1 445 Winter (December – March) 185 2.5 74 260 “Peak Hourly Flow” and “Maximum Daily Flow” were estimated using peaking factors from TR-16, as was done in the Phase I CWMP. Note that, typically wastewater is composed of residential, commercial and industrial sources. As was the case in both the Phase I CWMP and the 2004 CWMP/FEIR, industrial sources continue to be absent in Nantucket and therefore to be representative of current conditions and consistent with these reports, only residential and commercial flows are developed for this update. Infiltration and inflow (I/I) was estimated assuming 250 gallons per day-inch-mile (gpdim) for new pipe per MassDEP standards. Infiltration/inflow was not estimated for any low pressure sewer. The length of gravity sewer in Somerset presented in the 2004 CWMP was included in these calculations. The 2004 CWMP identified Madaket and Warrens Landing as being sewered with 100% low pressure. For the remaining needs areas, to determine the total length of sewer, the approximate length of streets within each area was extracted from GIS mapping. To be consistent with the Phase I CWMP, wastewater loads were calculated by applying industry standard factors from the New England Interstate Water Pollution Control Commission Guides for the Design of Wastewater Treatment Works (TR-16) to the estimated average daily wastewater flows. Nantucket, MA Projected and Existing Flows and Loads at the Surfside WWTF 10/22/2014 Table 2 - Influent Flows and Pollutant Loads Flow (MGD)BOD Load (lbs/day) TSS Load (lbs/day) Total Nitrogen Load (lbs/day) Average Daily - Summer Maximum Monthly Maximum Daily Peak Hourly Average Daily Maximum Monthly Average Daily Maximum Monthly Average Daily Maximum Monthly Projected by Study / Need Area Madaket 0.16 490 560 90 Warren's Landing 0.03 100 110 20 Hummock Pond South 0.07 200 230 40 Hummock Pond North 0.09 290 330 50 Somerset 0.10 320 360 60 Monomoy 0.08 260 300 50 Shimmo 0.06 190 220 30 Town 0.59 1,800 2,050 330 Nantucket PLUS 0.07 230 260 40 Miacomet 0.07 210 240 40 Subtotal Projected 1.33 1.42 1.82 3.52 4,090 4,660 750 Infiltration/Inflow 0.06 0.06 0.06 0.06 Total Projected 1.39 1.48 1.88 3.58 4,090 4,790 4,660 6,150 750 860 Existing Conditions at Surfside WWTF 1.53 1.64 2.10 4.06 4,990 5,830 3,490 4,610 530 610 Total Projected and Existing 2.92 3.13 4.00 7.74 9,080 10,620 8,150 10,760 1,280 1,470 \\DEDHAM\Projects\225139 Nantucket MA - CWMP Update\wip\Flows and Loads\2014.01.28 FlowsandLoads FINAL - JEH Summary Nantucket, MA (project #225139)Woodard & Curran CWMP Update September 2014 APPENDIX G: MADAKET WASTEWATER NATURAL HERITAGE AND ENDANAGED SPECIES PROGRAM MASSACHUSETTS HISTORICAL COMMISSION FAA Property Habitat Assessment and Rare Plant Species Inventory NHESP Tracking No. 09-26832 February 20, 2012 Prepared for: Woodard & Curran 980 Washington Street, Suite 325N Dedham, MA 02026 Prepared by: Rachael Freeman Laurentide Environmental 14 South Shore Road Nantucket, MA 02554 rachaelslosek@gmail.com laurentideenvironmental@comcast.com 1    Introduction In 1998, the Nantucket Department of Public works initiated a project to identify areas of the island with sub-surface wastewater disposal problems. The result was a two-part “Comprehensive Waste Water Management Plan and Environmental Impact Report”. Within this report, areas with wastewater disposal problems were ranked based on the severity of the issue and ways to mitigate or eliminate the problem were proposed. The west end of Nantucket was noted for having substantial disposal issues, resulting in the potential for both marine resources and ground water to be compromised. To mitigate disposal issues, the development of a new wastewater treatment facility at the former site of the FAA tower has been proposed. The FAA tower property is a 91.71 acre site located at the west end of Nantucket Island (Figure 1). The property is currently owned by the Federal Government and the Town of Nantucket is working to acquire the parcel. Red Barn Road bisects the property and there is a small building that was utilized when the FAA tower was on the site. With the exception of a few dirt roads and the small building, the property is currently undisturbed. The FAA property is considered Priority Habitat 15 (PH15) as defined by the Massachusetts Natural Heritage Atlas (13th Edition) for the following rare species: Scientific name Common Name Taxonomic Group State Status Amelanchier nantucketensis Nantucket Shadbush Plant Special Concern* Crocanthemum dumosum Bushy Rockrose Plant Special Concern Liatris scariosa var. novae-angliae New England Blazing Star Plant Special Concern Linum intercursum Sandplain Flax Plant Special Concern Scleria pauciflora Papillose Nut-Sedge Plant Endangered Sisyrinchium fuscatum Sandplain Blue-Eyed Grass Plant Special Concern Asio flammeus Short-Eared Owl Bird Endangered Circus cyaneus Northern Harrier Bird Threatened Podilymbus podiceps Pied-Billed Grebe Bird Endangered Abagrotis nefascia Coastal Heathland Cutworm Butterflies and Moths Special Concern Acronicta albarufa Barrens Daggermoth Butterflies and Moths Threatened Cingilia catenaria Chain Dot Geometer Butterflies and Moths Special Concern Cicindela purpurea Purple Tiger Beetle Beetle Special Concern * Amelanchier nantucketensis was a species of Special Concern in the state of Massachusetts when this project  began but was recently delisted.  Although there are a large number of rare species listed as being present on or in the vicinity of the FAA property, the decision was made to begin by focusing on plant surveys. The goals of the plant survey were to identify the vegetation communities on the property and determine the locations of any rare plants. Information about the vegetation communities or habitat types present on the property can be used to infer how other rare species may utilize the site. 2    Survey Protocol Plant surveys were performed between May 14 and September 21, 2011. To ensure that the entire site was surveyed, we established transect lines running from the northwest property line to the southeast property line in ArcGIS (ESRI ArcView 9.3, 2008). We used the “intersect” tool to place points 10m apart along each of the property lines. By connecting the points on the northwest and southeast property lines, we created 67 transects that ran the length of the site (Figure 2). These transect lines were uploaded to Trimble Geo XT and Trimble Juno GPS units, which were used to navigate the length of each line. These transects were primarily utilized during the initial surveys for Amelanchier nantucketensis. Not only could this plant theoretically be found throughout much of the site, it was the first survey of the property and so it was important that we cover the whole area to gain a better understanding of the habitat types. Subsequent plant surveys were performed by searching during the time each plant was most visible and within the specific habitat type where the plant occurs. In the initial survey design, transects were 10m apart. While walking adjacent transects in the field, we determined that it was easy to see between transects that were 20m apart and therefore the decision was made to survey every other transect line for the majority of the site. The vegetation on the eastern third of the property is extremely dense and is almost entirely a monoculture of 2-3m high Quercus ilicifolia. After navigating along a number of transects, we determined that the best use of our time would be had by only surveying a subset of transects in this area. In general, areas we felt demanded more intense survey, such as the frost valley, were more thoroughly searched while areas where we did not expect to locate any rare plants were less intensively searched. Habitat Assessment We used ArcGIS (ESRI ArcView 9.3, 2008) to define the vegetation communities present on the FAA property. First, we created polygons in ArcGIS (ESRI ArcView 9.3, 2008) by outlining the natural changes in vegetation visible on the 2007 aerial photographs of Nantucket Island. After the polygons were created, we utilized our knowledge of the plants on the FAA property to name and describe the community types present at the site. Rare Species Survey When a rare species was located, the species name, number of plants, and representative associated species were recorded. If there were relatively few individuals, and they could all be found within a 1m diameter circle, a GPS point was taken at the center of the occurrence. When a greater number of individuals were present, a line file showing the perimeter around all of the individuals was created. A polygon shapefile was created using the perimeter lines in ArcGIS (ESRI ArcView 9.3, 2008). Results Geology and Soils Nantucket Island was the southern terminus of the Wisconsin Glacier. The terminal moraine that transects the island from west to east was pushed ahead of the glacier and deposited as it retreated. The outwash plains on the south-western shore of Nantucket were formed as the melt waters of the glacier flowed to the ocean. The western end of the island, where the FAA site is located, is classified as “young outwash” because it was formed in the most recent retreat of the ice sheet. These younger outwash deposits are mostly gravelly sand with some pebble, cobble and local deposits of silt and clay (Odale 1992). 3    The soils types found on the FAA property are of the Evesboro and Riverhead associations (Figure 3). Specifically there is Evesboro A, which is a sandy soil with a low 0 – 3% slope, Evesboro B, which is similar but has a slightly greater 3 – 8% slope, and Riverhead A, which is a sandy loam with a low 0 – 3% slope. The Evesboro A, B, and Riverhead A soil types are all well-drained soils, with the Evesboro associations being excessively well-drained (Langlois 1979). Habitat Assessment Seven plant communities were identified on the FAA property (Figure 4). The names for the communities were primarily derived from the “Natural Communities” classifications utilized by the Massachusetts Natural Heritage and Endangered Species Program (Swain and Kearsley 2001). However, we created the community types “Huckleberry Heathland” and “Transitional Scrub Oak Shrubland” to describe areas of the FAA property where woody species are encroaching on early successional communities and they are transitioning to mid-successional communities. Often these transitional communities are not separated from the main vegetation communities but for the purpose of discussing habitat utilization by rare species and habitat management, we decided to increase the resolution of our assessment to include transition zones. Community Type Acres  Disturbed 0.85  Grassland 0.25  Huckleberry Heathland 5.6  Huckleberry Scrub Oak Heathland 17.66  Maritime Shrubland 1.44  Road 2.86  Sandplain Heathland 17.67  Scrub Oak Shrubland 28.24  Transitional Scrub Oak Shrubland 17.08  Disturbed Areas and Roads There are multiple dirt and abandoned roads that traverse the FAA property. The largest of these, Red Barn Road, travels from Massasoit Bridge over Long Pond and south to the beach. This road is heavily travelled year-round by automobiles and walkers. There are also two smaller roads that access the building in the center of the property. The dirt road that turns east off of Red Barn Road is passable with a car. Whereas, the road that proceeds directly north from the building can only be used for pedestrian access because several large pitch pines have decreased the width of the road. There are two abandoned road beds that proceed northeast from the building. The abandoned road to the west was mowed during the course of the study this summer. The timing of mowing was such that the rare species Sisyrinchium fuscatum and Crocanthemum dumosum, that had been observed growing there, could not be documented. 4    Although these roads are abandoned, they remain beneficial habitat for the rare plant species located on the FAA property. The dominant characteristic of the rare plant species and habitats documented on the FAA property is that they are disturbance-dependant. Without frequent disturbance, either in the form of mowing or prescribed fire, these habitats will become overgrown by Gaylussacia baccata, Quercus ilicifolia, and Pinus rigida. As the habitats undergo succession to later stage communities, the state-listed rare plant species that inhabit them are gradually pushed out. Grassland The only areas on the FAA property that qualify as grassland are located directly north of the former tower operations building. The reason for the dominance of grasses in this area is likely that the site was disturbed during the construction of the building and may have been mowed when the building was in use. The dominant herbaceous species include Agrostis spp, Dicanthelium spp., Euthamia caroliniana, Festuca spp., Panicum virgatum, and Schizachyrium scoparium. The rare species found within the grasslands at the FAA property are Crocanthemum dumosum, Sisyrinchium fuscatum, and Cingilia catenaria. Sandplain Grasslands are rare and valuable habitat. Although this area is dominated by grasses, it does not have the forb species diversity of a Sandplain Grassland and may be closer to a Cultural Grassland. Huckleberry-Scrub Oak Heathlands and Huckleberry Heathlands Dunwiddie et al. (1996) subdivided Heathlands into two associations: Tall Shrub and Low Shrub. The Tall Shrub Heathland is further divided into Mixed Maritime Shrubland and Huckleberry-Scrub Oak Heathland. The heathlands found on the FAA property are primarily Tall Shrub, Huckleberry – Scrub Oak Heathlands. This community is dominated by Gaylussacia baccata and Quercus ilicifolia but retains the interstitial spaces and grassy areas typical of a heathland. We added Huckleberry Heathlands to describe areas where Gaylussacia baccata dominates. Areas where there is a monoculture of Gaylussacia baccata are likely in transition from Sandplain Heathland to Huckleberry-Scrub Oak Heathland. Both these communities are found on well-drained soils and have a large component of sub-shrubs such as Arctostaphylos uva-ursi, Hudsonia ericoides and Vaccinium angustifolium. Interspersed between the shrubs are grass and forb species such as Carex pensylvanica, Danthonia spicata, Ionactis linariifollius and Schizachyrium scoparium (Swain and Kearsley 2001). Numerous rare plants and animals are found in Huckleberry-Scrub Oak and Huckleberry Heathlands. At the FAA property the following rare species that utilize this habitat were located: Amelanchier nantucketensis (delisted January 2012), Circus cyaneus, Hemileuca maia and Cingilia catenaria. Maritime Shrubland The shrubs on the south western edge of the FAA property are growing within a low lying swale that, closer to the coast, forms Sheep Pond. The combination of Gaylussacia baccata, Morella pensylvanica, Prunus serotina and Rosa spp. most closely resembles a Maritime Shrubland. The Maritime Shrubland community type is represented by low growing shrubs that may be regularly impacted by salt spray (Swain and Kearsley 2001). Although only brackish, there is great potential for salt spray from Sheep Pond and the ocean to impact this area during even small storm events. Sandplain Heathland The Sandplain Heathland located at the FAA property is known as a glacial plain community because the assemblage of dwarf shrubs is found growing on well-drained, glacially deposited, upland soils. The combination of low growing shrubs interspersed with grasses and forbs observed at the FAA site is typical of a Sandplain Heathland. Sandplain Heathlands and Sandplain Grasslands are very similar in 5    species composition but Heathlands have a greater proportion of shrub species. Grasslands are also known for having a higher diversity of vascular plants (Swain and Kearsley 2001). Dominant shrub species in Sandplain Heathlands include Arctostaphylos uva-ursi, Gaylussacia baccata, Hudsonia ericoides, Quercus ilicifolia and Vaccinium angustifolium. Carex pensylvanica and Schizachyrium scoparium are the dominant grasses and are interspersed with forb species such as Achillea millefolium, Sericocarpus asteroides and Tephrosia virginiana. Numerous rare plants and animals are found in Sandplain Heathlands. At the FAA property the following rare species that utilize this habitat were located: Amelanchier nantucketensis (delisted January 2012), Circus cyaneus, Hemileuca maia and Cingilia catenaria. This habitat is ranked as S1 in the state of Massachusetts, indicating that there are five or fewer “good” examples of this habitat type (Swain and Kearsley 2001). Scrub Oak Shrubland Scrub Oak Shrublands occur on dry, sandy soils and are dominated by tall (1-3m) Quercus ilicifolia and/or Quercus prinoides. The shrubs can be quite dense, often forming an impenetrable thicket. In areas where there is sufficient light penetration, additional species such as Arctostaphylos uva-ursi, Carex pensylvanica, Comptonia peregrina, Gaylussacia baccata, Photinia melanocarpa, Schizachyrium scoparium and Vaccinium angustifolium may be found. Scrub Oak Shrublands are important for several rare species of Lepidoptera, including Hemileuca maia, which was located on the site during 2011 surveys. This habitat is ranked as S1 in the state of Massachusetts, indicating that there are five or fewer “good” examples of this habitat type. (Swain and Kearsley 2001) Transitional Scrub Oak Shrubland The Transitional Scrub Oak Shrubland was constructed for the FAA property to describe the large areas of heathland that contain upwards of 50%, of Quercus ilicifolia. This community type may also be referred to as “Open Scrub Oak”. In addition to a greater proportion of Quercus ilicifolia, there are few to no open areas with sparse cover. For the most part, areas of heathland with increased cover and higher proportions of scrub oak are in the process of evolving from a Huckleberry-Scrub Oak Heathland to a Scrub Oak Shrubland community. Rare Species Surveys Amelanchier nantucketensis (Nantucket shadbush), Sisyrinchium fuscatum, Crocanthemum dumosum, Linum intercursum, and Liatris scariosa var. novae-angliae were all found on the FAA tower property. During the surveys, three additional rare species were recorded; a pair of Circus cyaneus (Northern Harrier, State Rank - Threatened), a single 3rd instar larva of Hemileuca maia (Coastal Barrens Buck moth, State Rank – Special Concern), and countless Cingilia catenaria (Chain Dot Geometer, State Rank – Special Concern). 6    Scientific name Common name Approximate bloom time or survey time on Nantucket State Rank Amelanchier nantucketensis Nantucket shadbush Early May Special Concern (Delisted January 2012) Crocanthemum dumosum bushy rockrose Late May to mid June Special Concern Liatris scariosa var. novae-angliae New England blazing star Late August to late-September Special Concern Linum intercursum sandplain flax July and early August Special Concern Scleria pauciflora var. caroliniana papillose nut-sedge Mid August to mid-September Endangered Sisyrinchium fuscatum sandplain blue-eyed grass Late May to early July Special Concern Amelanchier nantucketensis Amelanchier nantucketensis Bickn. (Rosaceae) was officially removed from the state list of Rare and Endangered Species in January 2012. However, we performed surveys for this species during our fieldwork in 2011 and therefore our findings are included in this report. Amelanchier nantucketensis is an upright, colonial shrub that can be up to 3m in height. The leaves are unexpanded at anthesis and buds are densely pubescent. After expansion, leaves become glabrous with a shiny upper surface and gray-green underside. Leaves are dentate and have an acute to acuminate tip. Fruits generally ripen in July (Haines 2011, Cullina and Polloni 2007). In Massachusetts, it blooms in May and early June and produces 4-10(15) cream colored flowers in a raceme. Flowers are diminutive, with short (≥7mm), spatulate petals. Short petal length and andropetally are the major characteristics that differentiate this species from others in the genus Amelanchier (Cullina and Polloni 2007). While Amelanchier arborea, Amelanchier laevis, and Amelanchier canadensis are also known from Nantucket, none have the diminutive petals that are characteristic of A. nantucketensis. There is ongoing discussion as to the existence of Amelanchier stolonifera on Nantucket. Sorrie and Dunwiddie (1996) list one historic collection of Amelanchier stolonifera (Amelanchier spicata) in his book “The Vascular and Non-Vascular Flora of Nantucket, Tuckernuck, and Muskeget Islands” but it is not considered to be commonly found on the island. Both Amelanchier nantucketensis and Amelanchier canadensis are found on Nantucket in similar habitats. To accurately identify this species, it must be observed in flower. Searches were performed for Amelanchier nantucketensis on May 14, 15, 18, 19 and 20, 2011. During that time, 55 occurrences were located for a total of 734 plants (Figure 5). All of the occurrences were located on the western two thirds of the property where the vegetation is not as dense. Amelanchier nantucketensis is known for inhabiting disturbed areas and 15 of the occurrences were located along road edges. Common associated species include Epigaea repens, Gaylussacia baccata, Morella pensylvania, Quercus ilicifolia, Vaccinium angustifolium, and Viburnum dentatum. 7    Crocanthemum dumosum Crocanthemum dumosum is a yellow, perennial wildflower that is found in the sandplain grasslands and sandplain heathlands throughout Nantucket. There are four species of rock-rose on Nantucket Island, Crocanthemum dumosum, Crocanthemum propinquum, Crocanthemum bicknellii, and Crocanthemum canadense. This species is a member of the taxonomically cryptic rockrose genus (Cistaceae). While the vast majority of the individuals can be attributed definitively to one species, there are situations where it is not clear. At least two species of Crocanthemum are known to occur commonly in sandplain grassland habitat: Crocanthemum dumosum and Crocanthemum propinquum. The primary characteristic that can be used to differentiate these two species is their growth form. Crocanthemum propinquum exhibits a clonal growth form and produces numerous short, upright, unbranched stems. In contrast, Crocanthemum dumosum is highly branched and while it can be low growing and grow in clusters, there are always distinct individuals. Crocanthemum dumosum and Crocanthemum canadense can be very challenging to differentiate when found growing in overlapping habitat. The dominant characters cited to differentiate the two species are the growth habit and density of pubescence on the mid-stem leaves. Crocanthemum dumosum is known to be densely pubescent with low lying and branched stems while Crocanthemum canadense has fewer leaf hairs and more upright stems. The other characteristic noted in Arthur Haines’ key (2011) is the papillae on the surface of the seeds. In Crocanthemum dumosum, the papillae are described as “low and broad” whereas the papillae in Crocanthemum canadense are described as “elongate”. Phenology is another trait that may aid in identifying individuals. Crocanthemum dumosum blooms earlier in the season than Crocanthemum canadense (Haines 2011). The timeframe and habitat for Sisyrinchium fuscatum and Crocanthemum dumosum searches overlapped and so flagging for both species was concurrent. Flagging for Sisyrinchium and Crocanthemum occurred on May 30, June 1, 13, 15, 18 through 22, July 6 and 11, 2011. We waited to GPS most plants until the end of August, specifically August 24, 29, and September 21, 2011, so that we could examine seeds and make conclusive species determinations when necessary. Any additional plants observed unflagged were marked at this time. At the FAA property there were three Crocanthemum species located; Crocanthemum dumosum, Crocanthemum propinquum, and Crocanthemum. canadense. Only Crocanthemum dumosum was GPSed. Nine hundred and forty-four individuals of Crocanthemum dumosum were located throughout the areas defined as sandplain heathland habitat (Figure 6). Common associated species include Arctostaphylos uva-ursi, Gaylussacia baccata, Morella pensylvanica, Rosa virginiana, Schizachyrium scoparium, and Sericocarpus asteroides. Liatris scariosa var. novae-angliae Liatris scariosa var. novae-angliae is a rare grassland perennial found primarily on road edges and in disturbed habitats throughout Nantucket. It is a member of the Asteraceae and is endemic to the Northeastern United States. Liatris scariosa var. novae-angliae is the only Liatris species found on Nantucket and is easily identifiable when it is in bloom by the purple, thistle-like flower heads it produces. Plants are able to reproduce for multiple years by over-wintering as a corm (Kane and Schmidt 2001). Searches for Liatris scariosa var. novae-angliae were performed on September 2 and 19, 2011. Sixty four Liatris scariosa var. novae-angliae were located on the FAA property. There were only two locations where plants were found and both were highly disturbed sites (Figure 7). The largest occurrence, 8    containing 57 plants, was located on the southern end of the triangle at the intersection of Red Barn and Sheep Pond Roads. Associated species include Arctostaphylos uva-ursi, Panicum virgatum, Rubus flagellaris, Schizachyrium scoparium and Gaylussacia baccata. Linum intercursum Linum intercursum Bickn. (Linaceae) is a small, perennial herb that flowers in late July and early August. The yellow flowers have five petals and are produced at the top of stiff ascending branches. The leaves are narrowly elliptic. Linum intercursum is generally found growing in colonies in open, upland habitats that are frequently disturbed (http://www.mass.gov/dfwele/dfw/nhesp/species_info/nhfacts/linint.pdf). A search for Linum intercursum was performed on August 8, 2011 and was restricted to areas within the frost valley that were very dry, open and grassy. One occurrence with three plants was located on the western edge of the frost valley (Figure 8). The associated species include Arctostaphylos uva-ursi, Gaylussacia baccata, Potentilla simplex, Rubus flagellaris, Schizachyrium scoparium, and Tephrosia virginiana. Scleria pauciflora var. caroliniana Scleria pauciflora is a taxonomically distinct species that is found in maritime grasslands and sandy soils on glacial till or outwash in the northeast. This member of the Cyperaceae is known from 12 sites in Massachusetts and is currently listed as endangered. There are two varieties of S. pauciflora known from New England: S. pauciflora var. caroliniana and S. pauciflora var. pauciflora. Although they are both listed as endangered in the state of Massachusetts, Scleria pauciflora var. caroliniana is the more common of the two varieties. The two varieties are differentiated by the degree of hairiness. Scleria pauciflora var. caroliniana is villous with hairs from 0.5 to 1mm long on the stems and leaves while S. pauciflora var. pauciflora is glabrous or sparsely hairy with hairs less than 0.4mm long. However, the two varieties are known to interbreed and therefore differentiating between them can be challenging (Zaremba 2004). Scleria pauciflora is most easily identifiable by the small, white achenes it produces in the fall post- flowering. The achenes are subglobose and when examined under a hand lens are visibly covered with small protrusions. A search for Scleria pauciflora was performed on September 19, 2011. Similar to Linum intercursum, the search for Scleria pauciflora was restricted to areas defined as sandplain heathland. No Scleria pauciflora was located even though there is appropriate habitat located on the property. Sisyrinchium fuscatum Sisyrinchium fuscatum is a perennial member of the Iridaceae (Iris family). This plant is differentiated from Sisyrinchium atlanticum, which is known from predominantly wetland habitats on Nantucket, by its persistent, thick, dark, fibrous leaf bases (Boufford 1997). Sisyrinchium fuscatum is cespitose. Inflorescences are borne singly on individual stems in June. Seed capsules are a light to medium brown color. 9    The timeframe and habitat for Sisyrinchium fuscatum and Crocanthemum dumosum searches overlapped and so flagging for both species was concurrent. Flagging for Sisyrinchium and Crocanthemum occurred on May 30, June 01, 13, 15, 18 through 22, July 6 and 11, 2011. Survey time was focused on areas of sandplain heathland and grassland. A total of 7205 Sisyrinchium fuscatum were found in the sandplain heathland and disturbed areas on the FAA property. The largest numbers of plants were concentrated in the frost valley that runs along the southern edge of the property from the southwest corner to the eastern property line (Figure 9). Common associated species include Arctostaphylos uva-ursi, Gaylussacia baccata, Morella pensylvanica, Rosa virginiana, Schizachyrium scoparium, and Sericocarpus asteroides. Additional Rare Species Three additional rare species, a pair of Circus cyaneus (Northern Harrier), a single 3rd instar larva of Hemileuca maia (Barrens buck moth), and large numbers of Cingilia catenaria (Chain dot geometer moths), were observed on the FAA property while rare plant surveys were being performed. The first, a pair of Northern Harriers (Circus cyaneus), is believed to have been nesting northwest of the old FAA tower operations building. Sightings of a male and female Circus cyaneus calling to each other were reported on May 19, 2011. The pair was flying near the house just beyond the northwest corner of the FAA property. The following day, May 20, a female Circus cyaneus was reported hunting at 10:30 am just north of the old FAA tower operations building. That afternoon, at 4:30pm, a male Circus cyaneus was reported hunting to the southeast of the FAA operations tower building. On June 1, at 2pm, a male Circus cyaneus was observed hunting to the south and east of the building. On June 5, a prey transfer was observed between a male and female Circus cyaneus at 5:30pm to the northwest of the building. Using the position of the prey transfer, we put an approximate nest location on the map (Figure 10). After the prey transfer, no more Circus cyaneus activity was noted and on June 13, an empty Circus cyaneus egg (Figure 11) with a piece missing was found slightly east of where the prey transfer occurred. Based on the appearance of the egg and after discussion with avian experts, we were informed that the nest was probably predated and the pair left. In addition, a single Hemileuca maia was found on a small Quercus ilicifolia in the frost valley on July 18, 2011 (Figure 12). The larva was a third instar larva and therefore quite large and noticeable (Figure 13). The bright yellow larva and white adults of the Cingilia catenaria (Figure 14) were observed throughout the heathlands on the FAA property (Figure 15) during June, July and August. No assessment of the number of larvae was performed but there were large areas where the vegetation, particularly, Gaylussacia baccata, was completely defoliated due to the larva. Adults were observed while performing surveys in September. Discussion Surveys at the FAA property clearly show that the site is host to a number of state-listed individual rare species as well as globally rare vegetation communities. The ecological value of such a property cannot be understated. However, there are a number of things to keep in mind when evaluating the results of this report. Our report shows that the greatest density of state-listed rare plant species is found within the early successional sandplain heathland, grassland, and disturbed habitats. While this is true, had we been surveying the property for rare Lepidoptera or Circus cyaneus habitat, the mid-successional scrub oak shrublands would appear equally important. Quercus ilicifolia is a primary host plant for a number of rare Lepidoptera, such as Hemileuca maia. Therefore, when examining our results and seeing the 10    predominance of rare species occurrences throughout certain areas of the property, it should be kept in mind that we are only showing the locations of rare plants and if other species were included, the maps would appear entirely different. When selecting how to define our vegetation communities, we elected to separate what we refer to as transition zones. We decided to do this because we felt it was important to show that the property itself is undergoing successional changes. Without management in the future, many of the areas that are currently sandplain heathland, huckleberry heathland and huckleberry scrub oak heathland will be further encroached upon by woody species and will continue transitioning towards scrub oak shrublands or pitch pine- scrub oak communities. Sandplain communities in the northeastern United States require periodic disturbance to be maintained (Lorimer and White 2002, Wagner et al. 2003). Prior to current fire suppression practices, fire was a common natural disturbance in sandplain habitats. The frequency of historic seasonal fires and severe summer wildfires resulted in fire-adapted plant communities. On Nantucket, intense sheep grazing was also a prominent form of disturbance. In the absence of severe fires or intensive grazing practices, a combination of mechanical cutting and prescribed fire may be used to achieve the varied landscape of a sandplain community (Wagner et al. 2003). Maintaining the current communities through management will help to preserve the abundant diversity that is present at the FAA property. Literature Cited Boufford, D. E. 1997. Sisyrinchium. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 12+ vols. New York and Oxford. Vol. 26, pp. 351. Dunwiddie, P., R. Zaremba, and K. Harper. 1996. A classification of coastal heathlands and sandplain grasslands in Massachusetts. Rhodora 98:117-145. Kane, A., and J. Schmitt. 2001. Liatris borealis Nuttall ex MacNab (Northern Blazing Star) Conservation and Research Plan. New England Wild Flower Society, Framingham, Massachusetts, USA. http://www.newfs.org Haines, A. 2011. The New England Wild Flower Society’s Flora Novae-Angliae. Yale University Press. 1008 p. Langlois, K. 1979. Soil survey of Nantucket County Massachusetts. USDA Soil Conservation Service and the Massachusetts Agricultural Station. 79 p. Lorimer, C. and A. White. 2003. Scale and frequency of natural disturbances in the northeastern United States: implications for early-successional forest habitat and regional age distributions. Forest Ecology and Management. 185: 41–64. Odale, R. 2001. Cape Cod and the Islands: the geologic story. On Cape Publications. 208 p. 11    Polloni, P. and M. Cullina. 2007. Conservation plan for Amelanchier nantucketensis. Massachusetts Division of Fisheries and Wildlife Natural Heritage and Endangered Species Program Report. MNHESP, Westborough, Massachusetts. Sorrie B. and P. Dunwiddie. 1996. The vascular and non-vascular flora of Nantucket, Tuckernuck, and Muskeget Islands. Massachusetts Audubon Society. 145 p. Swain, P. and J. Kearsley. 2001. Classification of the natural communities of Massachusetts. Version 1.3. Natural Heritage and Endangered Species Program, Division of Fisheries and Wildlife. Westborough, MA. Wagner, D., Nelson, M., and D. Schweitzer. 2003. Shrubland Lepidoptera of southern New England and southeastern New York: ecology, conservation, and management. Southeastern Forest Ecology and Management. 185: 95–112. Zaremba, Robert 2004. Scleria pauciflora Muhlenberg ex Willdenow var. caroliniana Alph. Wood and Scleria pauciflora Muhlenberg ex Willdenow var. pauciflora. (Fewflowered nut-rush) Conservation and Research Plan for New England. New England Wild Flower Society, Framingham, Massachusetts, USA. 12    13    14    15    16    17    18    19    20    21    22    Figure 11. Probable Circus cyaneus egg. 23    24    Figure 13. Third instar Hemileuca maia. 25    Figure 14. Larva and adult Cingilia catenaria. 26    27    28    28    TECHNICAL REPORT INTENSIVE (LOCATIONAL) ARCHAEOLOGICAL SURVEY MADAKET WASTEWATER TREATMENT FACILITY Nantucket, Massachusetts Dianna L. Doucette Submitted to: Woodard & Curran 980 Washington Street, Suite 325 Dedham, MA 02026 Submitted by: PAL 26 Main Street Pawtucket, Rhode Island 02860 PAL Report No. 2585 June 2013 PAL Publications CARTOGRAPHERS Dana M. Richardi/Jane Miller GIS SPECIALIST Jane Miller GRAPHIC DESIGN/PAGE LAYOUT SPECIALISTS Alytheia M. Laughlin/Gail M. Van Dyke i MANAGEMENT ABSTRACT PAL completed an Intensive (Locational) Archaeological survey for the proposed Madaket Wastewater Treatment Facility project area in Nantucket, Massachusetts. The proposed project will be located on 25- acres within an approximately 92-acre parcel between Massasoit Bridge Road and Red Barn Road at the eastern end of Nantucket. It will include the construction of a wastewater treatment facility consisting of tanks, equipment, an access road, and groundwater discharge site. The goal of the intensive (locational) archaeological survey was to determine the absence or presence of potentially significant archaeological sites. PAL personnel conducted extensive subsurface testing within the project area based on the results of the walkover survey and sensitivity ranking. Subsurface testing with 124, 50-x-50-cm test pits documented undisturbed and disturbed soil horizons within the project area, relatively little cultural material, and no subsurface or above ground features. A total of 42 artifacts were recovered including ceramic sherds, nails, shell, white-clay smoking pipe fragments, clam shell, and burned bone. The cultural material came from fill contexts or from the ground surface, and while it includes some early post-contact materials such as ceramics (e.g., redware, pearlware), hand-made brick, and white-clay pipe bowl fragments, there were also more recent finds such as wire nails and machine made clear bottle glass. The fill and surface contexts in which this material was recovered suggest that the deposits were likely redeposited, potentially during the construction of an unnamed dirt road running through the project area. The generally diffuse distribution of the cultural material assemblage from road fill contexts combined with the lack of any associated structural, landscape, or household features suggests that it is best characterized as yard/field scatter with no locational or associative integrity. Fill deposits in the project area contained a mixture of recent and historic cultural materials, demonstrating that the deposits are more recent. Analysis of the soil profiles and cultural material suggests that these fill deposits are likely related to road construction as well as more isolated utility installations, driveway construction, and landscaping events associated with an abandoned Federal Aviation Administration building with the larger 92-acre parcel. Based on the results of this survey, the proposed construction within the Madaket WWTF project area will not impact any potentially significant archaeological resources. No further archaeological investigations are recommended. PAL Report No. 2585 iii TABLE OF CONTENTS MANAGEMENT ABSTRACT ................................................................................................................... i 1. INTRODUCTION ................................................................................................................................ 1 Scope and Authority ............................................................................................................................... 1 Project Personnel .................................................................................................................................... 5 Disposition of Project Materials ............................................................................................................. 5 2. RESEARCH DESIGN AND FIELDWORK METHODOLOGIES ................................................ 6 Evaluating Significance and Historic Contexts ...................................................................................... 6 Archival Research .................................................................................................................................. 9 State Site Files and Reports, Artifact Collection Reports, and Town Reconnaissance Surveys ...... 9 Cultural Resource Management Reports ......................................................................................... 9 Professional Journal Articles and Other Publications .................................................................... 10 Histories and Maps ........................................................................................................................ 10 Environmental Studies ................................................................................................................... 11 Consultation.......................................................................................................................................... 11 Walkover Survey .................................................................................................................................. 11 Archaeological Sensitivity Assessment ................................................................................................ 11 Pre-Contact Period Archaeological Sensitivity .............................................................................. 12 Contact Period Archaeological Sensitivity .................................................................................... 13 Post-Contact Period Archaeological Sensitivity ............................................................................ 13 Archaeological Sensitivity Ranking .............................................................................................. 14 Subsurface Testing ............................................................................................................................... 15 Laboratory Processing and Analyses .................................................................................................... 16 Processing ...................................................................................................................................... 16 Cataloging and Analyses................................................................................................................ 16 Curation ................................................................................................................................................ 16 3. ENVIRONMENTAL CONTEXT ..................................................................................................... 17 Geomorphology and Surficial Deposits ............................................................................................... 17 Soils and Hydrology ............................................................................................................................. 19 Existing Conditions .............................................................................................................................. 20 4. CULTURAL CONTEXT ................................................................................................................... 21 Pre-contact Period ................................................................................................................................ 21 PaleoIndian Period (12,500–10,000 B.P.)...................................................................................... 21 Early Archaic Period (10,000–8000 B.P.) ..................................................................................... 23 Middle Archaic Period (8000–6000 B.P.) ..................................................................................... 23 Late Archaic Period (6000–3000 B.P.) .......................................................................................... 24 The Transitional Archaic Cremation Burial District of Nantucket, ca. 3800–2600 B.P. ..................... 24 Early Woodland Period (3000–1600 B.P.) .................................................................................... 26 Middle Woodland Period (1600–1000 B.P.) ................................................................................. 26 Late Woodland Period (1000–450 B.P.) ........................................................................................ 27 Contact Period (A.D. 1500–1620) ........................................................................................................ 28 Post-Contact Period .............................................................................................................................. 28 Plantation Period (1620–1675) ...................................................................................................... 28 Table of Contents iv PAL Report No. 2585 Native American Land Use and Settlement Patterns of the Miacomet Indian Village ca. A.D. 1693–1800 .......................................................................................................... 31 Federal Period (1775–1830) .......................................................................................................... 34 Early and Late Industrial Periods (1830–1915) ............................................................................. 36 Modern Period (1915–Present) ...................................................................................................... 38 5. RESULTS, INTERPRETATIONS, AND RECOMMENDATIONS ............................................. 40 Results ................................................................................................................................................. 40 Archival Research .......................................................................................................................... 40 Results of the Field Investigations ................................................................................................. 41 Interpretations and Recommendations ................................................................................................. 42 Recommendations ................................................................................................................................ 42 REFERENCES .......................................................................................................................................... 47 APPENDICES A CATALOG OF CULTURAL MATERIAL ..................................................................................... 57 B PROJECT CORRESPONDENCE ................................................................................................... 61 PAL Report No. 2585 v LIST OF TABLES Figure 1-1. Location of the Madaket Waste Water Treatment Facility project area on the Nantucket USGS quadrangle map ...................................................................................... 1 Figure 1-2. Map of the Madaket Waste Water Treatment Facility project area .................................... 2 Figure 3-1. Ice lobes of the Wisconsinan glaciation and the formation of end moraines (source: Oldale 1992) ........................................................................................................ 18 Figure 3-2. Geologic map of Nantucket Island showing the approximate location of the project area (source: Oldale 1992) ................................................................................................ 19 Figure 3-3. Photograph showing general project area conditions on either side of Red Barn Road, view north northwest .............................................................................................. 20 Figure 3-4. Photograph showing general project area conditions along dirt road in the facilities section of the project area, view northwest ....................................................................... 20 Figure 4-1. 1782 Map of Nantucket showing the approximate location of the project area (source: De Crevecoeur 1782) .......................................................................................... 41 Figure 4-2. Territories of major sachems at Nantucket and Tuckernuck in the late seventeenth century (source: Little 1988a:3, Figure 2) ........................................................................ 33 Figure 4-3. 1776 map of Nantucket showing the approximate location of the project area (source: DesBarres 1776) .................................................................................................. 35 Figure 4-4. 1869 map of Nantucket showing the approximate location of the project area (source: Ewer 1869) .......................................................................................................... 36 Figure 4-5. Map of Nantucket showing the location and ownership of farms in 1850 (source: Gardner and Gibbs 1946) .................................................................................... 37 Figure 4-6 1887 USGS map of Nantucket showing the approximate location of the project area (source: USGS 1901) ............................................................................................... 38 Figure 5-1. Location of intensive survey testing within the Madaket Waste Water Treatment Facility project area .......................................................................................................... 43 Figure 5-2. Representative soil profiles within the Madaket Waste Water Treatment Facility project area ........................................................................................................................ 45 Figure 5-3. Photograph showing test pit 19 along Transect F (TF-19) and general soil profile, view east ........................................................................................................................... 46 vi PAL Report No. 2585 LIST OF TABLES Table 2-1. Archaeological Sensitivity ................................................................................................ 15 Table 4-1. Pre-Contact Cultural Chronology for Southern New England ......................................... 22 Table 5-1. Summary of Cultural Material Recovered from the Madaket WWTF Project, Intensive Survey ............................................................................................................... 41 PAL Report No. 2585 1 CHAPTER ONE INTRODUCTION In response to a request from Woodard & Curran, on behalf of the Town of Nantucket, PAL completed archaeological investigations at the proposed Madaket Wastewater Treatment Facility (WWTF) project area in Nantucket, Massachusetts (Figure 1-1). The proposed project will be located on 25-acres within an approximately 92-acre parcel currently owned by the Federal Aviation Administration, between Massasoit Bridge Road and Red Barn Road at the eastern end of Nantucket. It will include the construction of a wastewater treatment facility consisting of tanks, equipment, an access road, and groundwater discharge site that will encompass approximately 25 acres of land not including buffer areas and/or land required for conservation protection (Figure 1-2). The project will also involve the installation of sewer pipe ranging from 1-1/4 to 4-inch diameter along existing roadways throughout the Madaket and Warren’s landing study areas, which will pump wastewater flows to the Madaket WWTF. The Massachusetts Historical Commission (MHC) commented on the Draft Environmental Impact Report (DEIR) for this project submitted by the Town of Nantucket back in 2004 (letter to MEPA Office May 3, 2004), and requested that an intensive (locational) archaeological survey (950 CMR 70) by conducted for the project impact areas. The proposed project area is included in the Nantucket Archaeological District, an island-wide designation that reflects the overall high archeological sensitivity of Nantucket. Native and EuroAmerican cultural resources have been documented across the island and represent nearly 10,000 years of continuous human land use. There are more than two dozen previously recorded Native American archaeological sites located within one and a half miles (2.4 kilometers) of the project area spanning back at least 5000 years. At the Hughes Site (19-NT-92), located 900-feet (275 meters) north of the study area on the east side of Long Pond, three human burials were found in the 1940s dating to the Late Woodland Period (ca. 1000 to 450 years ago). Undisturbed sections of the project area may be considered to be archaeologically sensitive and exhibit environmental characteristics that are favorable for ancient and historic period land use and occupation. The goal of the intensive (locational) archaeological survey will be to locate and identify any significant archaeological deposits that may be present within the project area. The intensive survey will also be designed to collect basic information on the locations and densities of cultural deposits and to make recommendations regarding the need for additional archaeological testing, if necessary. The results of the intensive survey will be used to facilitate consultation with the Massachusetts State Historic Preservation Officer (MA SHPO) regarding the potential impacts of the project in accordance with Section 106 of the National Historic Preservation Act of 1966 (as amended) (36 CFR 800). Scope and Authority The intensive (locational) archaeological survey (950 CMR 70) was conducted under State Archaeologist’s permit number 3253 issued by the MHC. The archaeological survey work was undertaken in accordance with the National Historic Preservation Act of 1966 as amended (36 CFR 800); the Secretary of the Interior’s Standards and Guidelines for Archaeology and Historic Preservation (48 FR 44716, September 29, 1983); the Advisory Council on Historic Preservation’s handbook Treatment of Chapter One 2 PAL Report No. 2585 Figure 1-1. Location of the Madaket Waste Water Treatment Facility project area on the Nantucket USGS quadrangle map. Introduction PAL Report No. 2585 3-4 Figure 1-2. Map showing proposed site plans for the Madaket Waste Water Treatment Facility. Introduction PAL Report No. 2585 5 Archaeological Properties (1980); Massachusetts General Laws, Chapter 9, Sections 26–27c as amended by Chapter 254 of the Acts of 1988 (950 CMR 71.00); and the MHC’s handbook Public Planning and Environmental Review: Archeology and Historic Preservation (1985). This technical report follows the guidelines established by the National Park Service (NPS) in the Recovery of Scientific, Prehistoric, Historic, and Archeological Data (36 CFR Part 66, Appendix A) and by the MHC. The intensive survey fieldwork was conducted the week of May 20, 2013 utilizing the methodology outlined in the technical proposal for this project. Project Personnel PAL personnel involved in the project included Dianna L. Doucette (project manager and principal investigator), Kirk VanDyke (project archaeologist), Jesse Daubert, Dawn Beemer, Yvonne Benny- Basque, John Campbell, and Shawn Joy (archaeological assistants). Laboratory processing and analyses of recovered cultural materials were undertaken at the PAL laboratory facility in Pawtucket, Rhode Island under the supervision of Heather Olson. Disposition of Project Materials All project information (i.e., artifacts, field recording forms, maps, photographic records, etc.) is currently on file at PAL, 26 Main Street, Pawtucket, Rhode Island. PAL serves as a temporary curation facility until a final repository is designated by the Commonwealth of Massachusetts. 6 PAL Report No. 2585 CHAPTER TWO RESEARCH DESIGN AND FIELDWORK METHODOLOGIES The goal of the intensive (locational) archaeological survey of the Madaket WWTF project area was to locate and identify any significant archaeological properties that might be affected by project activities. To accomplish this objective, two research strategies were used: • archival research, including a review of literature and maps; and • field investigations, consisting of a “walkover” visual reconnaissance survey and subsurface testing. The archival research and walkover survey provided the information needed to develop environmental and historic contexts for the project area and develop a predictive model for archaeological sensitivity. Archaeological sensitivity is defined as the likelihood for belowground cultural resources to be present and is based on various categories of information: • locational, functional, and temporal characteristics of previously identified cultural resources in the project area or vicinity; and • local and regional environmental data reviewed in conjunction with existing project area conditions documented during the walkover survey, and archival research about the project area’s land use history. Subsurface archaeological testing was conducted in areas determined during the sensitivity assessment to have high or moderate potential for containing archaeological deposits. Evaluating Significance and Historic Contexts The different phases of archaeological investigation (survey, evaluation, and data recovery) reflect preservation planning standards for the identification, evaluation, registration, and treatment of archaeological resources (NPS 1983). An essential component of this planning structure is the identification of archaeological and traditional cultural properties that are eligible for inclusion in the National Register, the official federal list of properties that have been studied and found worthy of preservation. Archaeological properties can be a district, site, building, structure, or object, but are most often sites and districts (Little et al. 2000). Traditional cultural properties are defined generally as ones that are eligible for inclusion in the National Register because of their association with cultural practices or beliefs of a living community that (a) are rooted in that community’s history, and (b) are important in maintaining the continuing cultural identity of the community (Parker and King 1998). The results of professional surveys and consultation with Native American or other ethnic communities are used to make recommendations about the significance and eligibility of archaeological and traditional cultural properties. An archaeological property may be pre-contact, post-contact, or contain components from both periods. Pre-contact (or what is often termed “prehistoric”) archaeology focuses on the remains of indigenous Research Design and Methodology PAL Report No. 2585 7 American societies as they existed before substantial contact with Europeans and resulting written records (Little et al. 2000). In accordance with the NPS guidelines, the term “pre-contact” instead of “prehistoric” is used unless directly quoting materials that use the term “prehistoric.” The date of contact varies across the country and in the New England region. There is no single year that marks the transition from pre-contact to post-contact. Post-contact (or what is often termed “historical”) archaeology is the archaeology of sites and structures dating from time periods since significant contact between Native Americans and Europeans. Documentary records as well as oral traditions can be used to better understand these properties and their inhabitants (Little et al. 2000). Again, for reasons of consistency with the NPS guidelines, the term “post-contact” instead of “historical” is used when referring to archaeology unless directly quoting materials that use the term “historical.” The NPS has established four criteria for listing significant properties in the National Register (36 CFR 60). The criteria are broadly defined to include the wide range of properties that are significant in American history, architecture, archaeology, engineering, and culture. The quality of significance may be present in districts, sites, buildings, structures, and objects that possess integrity of location, design, setting, materials, workmanship, feeling, and association. The criteria allow for the listing of properties: A. that are associated with events that have made a significant contribution to the broad patterns of our history; or B. that are associated with the lives of persons significant in our past; or C. that embody the distinctive characteristics of a type, period, or method of construction, or that represent the work of a master, or that possess high artistic values, or that represent a significant and distinguishable entity whose components may lack individual distinction; or D. that have yielded, or may be likely to yield, information important to prehistory or history. Archaeological and traditional cultural properties can be determined eligible for listing in the National Register under all four criteria (Little et al. 2000; Parker and King 1998). Significance under any of these criteria is determined by the kind of data contained in the property, the relative importance of research topics that could be addressed by the data, whether these data are unique or redundant, and the current state of knowledge relating to the research topic(s). A defensible argument must establish that a property “has important legitimate associations and/or information value based upon existing knowledge and interpretations that have been made, evaluated, and accepted” (McManamon 1990:15). The criteria are applied in relation to the historic contexts of the resources. A historic context is defined as follows: A historic context is a body of thematically, geographically, and temporally linked information. For an archaeological property, the historic context is the analytical framework within which the property’s importance can be understood and to which an archaeological study is likely to contribute important information (Little et al. 2000). For traditional cultural properties, a historic context is further defined as follows: A historic context is an organization of available information about, among other things, the cultural history of the area to be investigated, that identifies “the broad patterns of development in an area that may be represented by historic properties” (48 FR 44717). The traditions and lifeways of a planning area may represent such “broad patterns,” so information about them should be used as a basis for historic context development. Chapter Two 8 PAL Report No. 2585 Based on federal standards and guidelines, groups that may ascribe traditional cultural values to an area’s historic properties should be contacted and asked to assist in organizing information on the area (Parker and King 1998). The formulation of historic contexts is a logical first step in the design of an archaeological investigation and is crucial to the evaluation of archaeological and traditional cultural properties in the absence of a comprehensive survey of a region (NPS 1983:9). Historic contexts provide an organizational framework that groups information about related historic properties based on a theme, geographic limits, and chronological periods. A historic context should identify gaps in data and knowledge to help determine what is significant information that may be obtained from the resource. Each historic context is related to the developmental history of an area, region, or theme (e.g., agriculture, transportation, waterpower), and identifies the significant patterns of which a particular resource may be an element. Only those contexts important to understanding and justifying the significance of the property must be discussed. Historic contexts are developed by: • identifying the concept, time period, and geographic limits for the context; • collecting and assessing existing information within these limits; • identifying locational patterns and current conditions of the associated property types; • synthesizing the information in a written narrative; and • identifying information needs. “Property types” are groupings of individual sites or properties based on common physical and associative characteristics. They serve to link the concepts presented in the historic contexts with properties illustrating those ideas (NPS 1983; 48 FR 44719). A summary of an area’s history can be developed by a set of historical contexts. This formulation of contexts is a logical first step in the design of any archaeological survey. It is also crucial to the evaluation of individual properties in the absence of a comprehensive survey of a region (NPS 1983:9). The result is an approach that structures information collection and analyses. This approach further ties work tasks to the types and levels of information required to identify and evaluate potentially important cultural resources. The following research contexts have been developed to organize the data relating to the Native American and Euro-American cultural resources identified within the proposed project area: a. Native American land use and settlement in the central outwash plains region of Nantucket Island, circa (ca.) 12,500 to 350 years before present (B.P.); and b. Historic Native American and Euro-American land use and settlement patterns in the central outwash plains region of Nantucket Island, ca. A.D. 1650 to present. These historical contexts, along with expected property types and locational patterns, are discussed in detail in Chapter 4. An evaluation of the survey findings, along with management recommendations, is presented in Chapter 5. Research Design and Methodology PAL Report No. 2585 9 Archival Research The development of a historic context and a predictive model of expected property types and densities within the project area began with archival research, consisting of an examination of primary and secondary documentary sources. These sources include written and cartographic documents relating both to past and present environmental conditions as well as documented/recorded sites in the general project area. The information contained in archival sources formed the basis of the predictive models developed for the project area, and were an integral part of the archaeological survey. Specific sources reviewed as part of the archival research for the Madaket WWTF project area include: State Site Files and Reports, Artifact Collection Reports, and Town Reconnaissance Surveys State site files maintained at the MHC offices in Boston were examined to obtain information about the location, temporal period, and other data about known pre- and post-contact sites, structures, or districts in the vicinity of Madaket Road. Known sites as they are reported to the state are plotted on a United States Geological Survey (USGS) topographic map and given an official site number. Each number is keyed to an individual file containing all available information about that site. Many of the known pre- and post-contact sites in the central outwash plains region of Nantucket were recorded during the 1970s as a result of private artifact collection inventories. Some site forms contain information about the types of artifacts recovered, although many of the known sites are simply the reported locations of artifact finds, with no additional information regarding site size, characteristics, contents, etc. A regional synthesis of pre- and post-contact settlement and goals for future research in the region was consulted (Historic and Archaeological Resources of Cape Cod and the Islands, MHC 1987). The MHC town reconnaissance survey report for Nantucket (MHC 1984b) provided general information about the pre- and post-contact cultural chronology and archaeological resource potential for the island. Cultural Resource Management Reports Numerous cultural resource management (CRM) reports from project areas across the island as well as within the immediate project area vicinity have contributed to a general reconstruction of Nantucket’s pre- and post-contact land use and settlement patterns. Since 1988, PAL has completed several CRM studies in the area directly surrounding the current project area and much of this previously accumulated information was synthesized in these reports and extracted and adapted for inclusion in the current report. PAL recently completed surveys for the 2 Fairgrounds Road (Elquist and Doucette 2007), Ellen’s Way Subdivision (Doucette 2007), and the proposed Nantucket Human Services Center at the corner of Miacomet Road and Surfside Road (PAL 2007; Rainey and Ingham 2005). In addition, PAL has completed surveys of the proposed Old South Road, Polpis, Fairgrounds Road, Nobadeer Farm Road, Quaker Road, and Cliff Road bicycle paths (Rainey 2001, 2004; Doucette 2008b; Doucette 2009; Doucette and Gillis 2010), Nantucket Memorial Airport property (Rainey 1998; Willan and Ritchie 1995), Nobadeer Recreational Facility (Doucette 2008a), Nantucket High School (Rainey and Ritchie 1998; Ritchie 1988), Wannacomet Water Company (Ingham and Rainey 2005b), Miacomet Golf Course (Rainey and Ritchie 1997, 2001), within town-owned land slated for a newly proposed golf course (Rainey 2000), Nantucket Disc Golf (Ritchie 2010), and for a proposed new Post Office (Ingham and Rainey 2005a). PAL conducted archaeological surveys associated with Nantucket High School (Rainey and Ritchie 1998; Ritchie 1988 ), Wannacomet Water Company (Ingham and Rainey 2005b) and Miacomet Golf Course (Rainey and Ritchie 1997). Of particular significance to the project area is the proximity of the Miacomet Indian burying grounds and territory associated with the historic Miacomet Indian village. Information about the history and archaeology of this settlement was drawn from the reports of archaeological Chapter Two 10 PAL Report No. 2585 investigations of the Nantucket Housing Authority project area on Surfside Road (Donta and Mullholland 1994). Discovery and partial excavation of eighteenth-century Native American domestic and institutional sites likely associated with the Miacomet settlement on Cow Pond Lane and Miacomet Road provided further site specific information about the Miacomet settlement as well as data from documentary sources relating to the eighteenth-century colonial practice of allowing indentured Native Americans to reside on common lands outside Nantucket town center (PAL 2004; Rainey and Ingham 2005). Professional Journal Articles and Other Publications Archival information for this project was drawn in part from the Nantucket Algonquin Studies, a series of research manuscripts developed by Elizabeth Little under the auspices of the Nantucket Historical Association (NHA) (Little 1983, 1988a, 1988b). These papers address specific and general issues in the subjects of archaeology, ethnohistory, and linguistics on Nantucket Island and include mainly primary source materials. Of particular relevance to sections of the project area was the Nantucket Algonquian Studies No. 12, History of the Town of Miacomet (Little 1988a) and No. 4, Historic Indian Houses of Nantucket (Little 1981). A more recent discourse by Dr. Little (1996) on the eighteenth-century Nantucket Sachem Spotso was consulted. Finally, a manuscript by Aimee E. Newell, Curator of Collections for the NHA, provided new insights specific to the twentieth-century agricultural history of the project area (Newell 2001). The majority of journal articles referenced in this report were cited for their information pertaining to Nantucket prehistory in general. The Bulletin of the Massachusetts Archaeological Society (MAS) contains a number of references to archaeological sites and finds on Nantucket Island (Bullen and Brooks 1948; Little 1984; Trinkaus 1982). Other journals containing information used in this report included the Bulletin of the Archaeological Society of Connecticut (Pretola and Little 1988) and Man in the Northeast (Little and Andrews 1982). Histories and Maps Several histories of Nantucket were consulted as part of the development of the project area’s general and specific historic context. The principal early, secondary sources used included Macy (1972), Starbuck (1924), and Worth (1992). Descriptions of the evolution and history of the whaling industry were drawn primarily from Hohman (1928) and Starbuck (1989). A more recently published analysis of Nantucket’s social and political history from 1660 to 1820 provided a contemporary and scholarly assessment of the island’s historic development (Byers 1987). Incidental information has been taken from several other secondary histories (Barber 1839; Douglas-Lithgow 1911; Forman 1966; Goodwin 1879; Karr 1995; Marshall 1962; Mooney and Sigourney 1980). Other histories reviewed included ethnohistoric accounts that describe early Nantucket and the Native American groups occupying the island during and after the contact period (de Crevecoeur 1971; Gookin 1806), the Massachusetts Historical Society collections (early-nineteenth-century volumes), and other original documents housed in the Foulger Museum Research Center collections (Macy 1972). General histories and historical maps and atlases were examined to assess changes in land use, and to locate any historic sites, structures, roads, bridges, or other landscape features that might exist within the project area. Reviewed maps included de Crevecoeur (1782), DesBarres (1776), Ewer (1869), Mitchell (1838), Prescott (1831), Walling (1856), and the 1901 USGS map. Research Design and Methodology PAL Report No. 2585 11 Environmental Studies Environmental data regarding the project area geomorphology, soils, hydrology/drainage, and vegetation composition was collected. Bedrock and surficial geological studies provided information about the region’s physical structure and history, and about geological resources near the project area (Chamberlain 1964; Oldale 1992). The United States Department of Agriculture (USDA) Soil Conservation Service soil survey (Langlois 1979) supplied information about soil types and surficial deposits within the project area and the general categories of flora and fauna that these soil types support. In addition, studies of past environmental settings of New England were consulted (Dunwiddie 1990). The discussion of existing conditions was based on observations made during the walkover survey. Consultation Since the current project is considered an undertaking under Section 106 of the National Historic Preservation Act of 1966, as amended, PAL coordinated with interested Native American groups and historical commissions. In this regard, PAL sent letters to the Aquinnah Wampanoag and Mashpee Wampanoag tribal historic preservation officers (THPOs). Follow up telephone and e-mail contact was made informing them of the project’s field schedule. Walkover Survey A walkover survey was conducted to collect environmental information and to examine the current physical condition of the project area. Topography, vegetation, and soils were considered. The current physical condition of the project area is defined by the degree of disturbance to the natural landscape. Disturbances may occur as a result of plowing, gravel or soil mining, or construction and site preparation activities. These conditions usually affect the potential for cultural resources to be discovered in their original archaeological contexts. Plowing, which can move artifacts from their original vertical and horizontal contexts, is the most common type of disturbance in New England. The consequences of plowing are not as severe as the effects of soil or gravel mining, which may completely remove archaeological deposits. Another purpose of the walkover was to note surface indications of archaeological sites. While pre- contact sites in New England are most often found belowground, artifact scatters are sometimes exposed on the surface through cultural and natural processes such as road use, gravel pitting, construction activity, or erosion. Historic Native American or Euro-American sites types that might be visible include cellar holes, structural remains, trash deposits, or landscape features. Archaeological Sensitivity Assessment Information collected during the archival research and walkover survey was used to develop a predictive model of potential site types and their cultural and temporal affiliation. The development of predictive models for locating archaeological resources has become an increasingly important aspect of CRM planning. The predictive model considers various criteria to rank the potential for the Madaket WWTF project area to contain archaeological sites. The criteria are proximity of recorded and documented sites, local land use history, environmental data, and existing conditions. The project area was stratified into zones of expected archaeological sensitivity to determine which areas would be tested. Chapter Two 12 PAL Report No. 2585 Pre-Contact Period Archaeological Sensitivity Archaeologists have documented 12,500 years of pre-contact Native American occupation of the region, and oral traditions of some contemporary tribes tell of a 50,000-year cultural legacy. Prior to 7,000 years ago, peoples focused primarily on inland-based resources, hunting and collecting along the Northeast’s waterways. After 7,000 years ago, settlement became more concentrated within the region’s major river drainages. By 3,000 years ago, concurrent with a focus on coastal and riverine settlement, large populations were living in nucleated settlements and developing complex social ties, with language, kinship, ideology, and trade linking peoples across the Northeast. During the centuries prior to European contact, these groups began to coalesce into the peoples known as Pocumtucks, Nipmucks, Massachusetts, Wampanoags, Pokanokets, Mohegans, Pequots, and Narragansetts. The chronology of the pre-contact period is presented in detail in Chapter 4. Assessing the pre-contact archaeological sensitivity of any given project area depends on a consideration of past and present geographical and ecological characteristics, known site location databases, and knowledge of distinctive temporal and cultural patterns. The choices that pre-contact Native Americans made about where they settled, how they organized themselves, and their technologies were all results of the dynamic relationship between culture and environment. Predictive modeling for larger-scale site location in southern New England has its roots in academic research including Dincauze’s (1974) study of reported sites in the Boston Basin and Mullholland’s (1984) dissertation research about regional patterns of change in pre-contact southern New England. Peter Thorbahn applied ecological modeling and quantitative spatial analysis, synthesizing data from several hundred sites in southeastern New England (Thorbahn et al. 1980), demonstrating that the highest concentration of pre-contact sites occurred within 300 meters (m) of low-ranking streams and large wetlands. The distribution of sites found along a 14-mile I-495 highway corridor in the same area reinforced the strong correlations between proximity to water and site locations (Thorbahn 1982). These and other large-scale projects provided data toward developing models of Native American locational and temporal land use (MHC 1982a, 1982b, 1984a; RIHPC 1982) that became the foundation for site predictive modeling employed during CRM surveys through the next two decades. Today, assessment of archaeological sensitivity within a given project area, and the sampling strategy applied to it, continues to take existing physiographic conditions into consideration but at multiple scales, from bedrock geology, to river drainages, to microenvironmental characteristics. These categories of data are used to establish the diversity of possible resources through time, the land use patterns of particular cultures, and the degree to which the landscape has been altered since being occupied (Leveillee 1999). Increasingly, social and cultural perspectives, as reflected in both the archaeological and historical records (Johnson 1999), and as expressed by representatives of existing Native American communities (Kerber 2006), are being taken into consideration when assessing archaeological sensitivity. Archaeological sampling strategies have also been evaluated and refined through applications of quantitative analyses (Kintigh 1992). Geologic data provides information about lithic resources and about current and past environmental settings and climates. Bedrock geology helps to identify where raw materials for stone tools were obtained by pre-contact groups and gives indications of how far from their origin lithic materials may have been transported or traded. The variety and amount of available natural resources are dependent on soil composition and drainage, which also play a significant role in determining wildlife habitats, and forest and plant communities. Geomorphology assists in reconstructing the paleoenvironment of an area and is particularly useful for early Holocene (PaleoIndian and Early Archaic Period) sites in areas that are different physically than they were 10,000 years ago (Simon 1991). Recent landscape changes such as drainage impoundments for Research Design and Methodology PAL Report No. 2585 13 highways and railroads, the creation of artificial wetlands to replace wetlands impacted by construction, or wetlands drained for agricultural use, can make it difficult to assess an area’s original configuration and current archaeological potential (Hasenstab 1991:57). Beyond predicting where sites are located, archaeologists attempt to associate cultural and temporal groups with changes in the environmental settings of sites. Changes in the way pre-contact groups used the landscape can be investigated through formal multivariates such as site location, intensity of land use, and specificity of land use (Nicholas 1991:76). However, distinguishing the difference between repeated short-term, roughly contemporaneous occupations and long-term settlements is difficult and can make interpreting land use patterns and their evolution problematic (Nicholas 1991:86). Contact Period Archaeological Sensitivity The contact period in New England roughly dates from AD 1500 to 1650, and predates most of the permanent Euro-American settlements in the region. This period encompasses a time when Native and non-Native groups interacted with one another through trade, exploration of the coastal region, and sometimes conflict. While contact period sites are usually associated with Native American activity during this period, they can also include sites utilized by Native and non-Native groups such as trading posts. Native settlement patterns during the contact period are generally thought to follow Late Woodland traditions, but with an increased tendency toward the fortification of village settlements. Larger village settlements are frequently expected along coastal and riverine settings, often at confluences. Inland villages are known to occur near swamp systems, which were exploited both as resource areas and as places of refuge in the event of attack. Such sites would likely contain material remnants reflecting the dynamics of daily life, trade, and preparedness for defense. The identification of contact period deposits is most frequently tied to the types of artifacts located within archaeological sites. Unfortunately, the majority of the archaeological data for this period in southern New England comes from the analysis of grave goods within identified Native American burial grounds, rather than from habitation sites and/or activity areas (Gibson 1980; Robinson et al. 1985; Simmons 1970). The available data suggest that sites dating to this period often contain traditionally pre-contact features and artifacts (e.g., storage pits, chipped-stone tools) as well as non-Native trade goods and objects (e.g., glass beads, iron kettles and hoes) (Bragdon 1996). The earliest contact period sites are often located at or near the coast and estuarine margin, since European visits to New England occurred via ship. Non-Native artifacts passed from the coastal region to the interior through trade and/or seasonal travel. Post-Contact Period Archaeological Sensitivity The landscape of a project area is used to predict the types of post-contact period archaeological sites likely to be present. Major locational attributes differ according to site type. Domestic and agrarian sites (houses and farms) are characteristically located near water sources, arable lands, and transportation networks. Industrial sites (e.g., mills, tanneries, forges, and blacksmith shops) established before the late nineteenth century are typically located close to waterpower sources and transportation networks. Commercial, public, and institutional sites (e.g., stores, taverns, inns, schools, and churches) are usually situated near settlement concentrations with access to local and regional road systems (Ritchie et al. 1988). Written and cartographic documents aid in determining post-contact period archaeological sensitivity. Historical maps are particularly useful for locating sites in a given area, determining a period of Chapter Two 14 PAL Report No. 2585 occupation, establishing the names of past owners, and providing indications of past use(s) of the property. Town histories often provide information, including previous functions, ownership, local socioeconomic conditions, and political evolution, which is used in the development of a historic context and to assess the relative significance of a post-contact period site. The written historical record, however, tends to be biased toward the representation of Euro-American cultural practices and resources, particularly those of prominent individuals and families. Archival materials generally are less sensitive to the depiction of cultural resources and activities associated with socioeconomically or politically “marginalized” communities (MacGuire and Paynter 1991; Scott 1994). These communities may include, but are not limited to, Native Americans, African-Americans, and “middling” farming or working-class Euro-Americans. Several archaeological studies conducted throughout New England have demonstrated the methodological pitfalls of relying exclusively on documentary or cartographic materials as a means to identify potential site locations associated with these types of communities. A large-scale archaeological study by King (1988) showed that in rural areas only 63 percent of the sites discovered were identifiable through documentary research. This suggests that approximately one-third of New England’s rural Euro-American archaeological sites may not appear on historical maps or in town and regional histories. More recent archaeological and ethnohistoric studies in the region have focused on the identification of other historically “invisible” communities, notably post-contact Native American communities. Several townwide surveys in southeastern Massachusetts have compiled archaeological and historical data about eighteenth- and nineteenth-century Native and African-American communities that are poorly represented or are altogether absent in written town histories (Herbster and Cox 2002; Herbster and Heitert 2004). In central Massachusetts, active and influential Native Americans have been identified through archival research despite the recorded “disappearance” of this group in the early eighteenth century (Doughton 1997, 1999). The cultural continuity of groups such as the Aquinnah Wampanoag is more thoroughly documented in archival sources, but until recently archaeologists focused their attention on pre-contact archaeological deposits. Current studies include predictive models for distinctly Native American post- contact sites, as well as interpretations of eighteenth- through twentieth-century archaeological sites (Cherau 2001; Herbster and Cherau 2002). Information about post-contact period land use within a project area can also be collected through written and oral histories passed through family members and descendant communities. These types of information sources can often fill in gaps in the documentary record and provide details that are not available through more conventional archival sources. While informants and other oral sources are subject to contradictory interpretations just like the documentary record, this type of information can also provide important data for the identification and interpretation of archaeological sites. The sole use of and reliance on the written and oral historical records during archival research, however, can lead to an underestimation of the full range of post-contact period sites in any given region. Therefore, walkover surveys and subsurface testing, in conjunction with the critical evaluation of available documentary and cartographic resources, are required to locate and identify underdocumented post-contact sites. Archaeological Sensitivity Ranking The project area was ranked according to the potential for the presence of cultural resources based on information collected during the background research and walkover. Subsurface testing was planned for areas assigned high and moderate sensitivity rankings and where project impacts will occur. Table 2-1 is a summary of the different factors used to develop the archaeological rankings. Research Design and Methodology PAL Report No. 2585 15 Table 2-1. Archaeological Sensitivity Ranking. Presence of Sites Proximity to Favorable Cultural/Environmental Characteristics Degree of Disturbance Sensitivity Ranking Known Unknown < 150 m > 150 < 500 m > 500 m None/Minimal Moderate Extensive • • • High • • • High • • • Low • • • High • • • High • • • Low • • • High • • • High • • • Low • • • High • • • Moderate • • • Low • • • Moderate • • • Moderate • • • Low • • • Moderate • • • Low • • • Low Subsurface Testing Subsurface testing was conducted in proposed project impact areas with moderate and high archaeological sensitivity to locate and identify any archaeological resources. A total of 124 test pits was excavated within the proposed infiltrator and facilities parcels of the Madaket WWTF project area. These test pits, 50-x-50 centimeters (cm) in size, were excavated along eight linear transects. All test pits were excavated by shovel in arbitrary 10-cm levels to sterile subsoil, unless impediments to excavation such as rocks, bedrock, or roots were encountered. Excavated soil was hand-screened through ¼-inch hardware cloth, and all cultural materials remaining in the screen were bagged and tagged by level within each unit. The count and type of all recovered cultural material were noted. Soil profiles, including depths of soil horizons, colors, and textures, were recorded for each test pit on standard PAL test pit profile forms. All test pits were filled and the ground surface was restored to its original contour following excavation. Digital images were taken of the general project area. Chapter Two 16 PAL Report No. 2585 Laboratory Processing and Analyses Processing The cultural material recovered from the Madaket WWTF project area during the archaeological investigations was organized by site and provenience and recorded and logged in on a daily basis. Cultural material was cleaned with tap water. Cataloging and Analyses The cultural material was cataloged using a customized computer program designed in Microsoft Access 2000. The program is a relational database, which provides the flexibility that is needed when cataloging archaeological collections that often contain disparate cultural materials such as stone, ceramics, and/or glass. Artifacts with similar morphological attributes are grouped into lots, which allows for faster and more efficient cataloging. The artifacts are stored in 2-millimeter thick polyethylene resealable bags with an acid-free tag containing provenience identification information. The artifacts are placed in an acid-free box that was labeled and stored in PAL’s curatorial facility in accordance with current NPS standards. Non-lithic artifacts were cataloged by material (e.g., ceramic, glass, coal, synthetic) and functional (e.g., plate, bowl, bottle, building material) categories. Artifacts having known dates of manufacture such as ceramics were also identified in terms of type (e.g., redware, pearlware, whiteware) when possible. In addition, ceramic sherds and bottle glass were examined for distinguishing attributes that provide more precise date ranges of manufacture and use. These included maker’s marks, decorative patterns, and embossed or raised lettering. Tentative dating of post-contact archaeological resources was performed using ceramic indices according to Hume (1969), Miller (1990, 1991), Miller and Hurry (1983), and South (1977). An analysis of the different nail and bottle types was used to refine the tentative date ranges of historic occupation generated by the ceramic assemblages. The analyses of the cultural materials recovered during the archaeological investigations also included mapping the density and horizontal and vertical distribution of these materials within the project area. Given the preliminary nature of the survey and the relatively small sample of cultural material recovered, analysis was limited to these basic tasks. Curation Following laboratory processing and cataloging activities, all recovered cultural material was placed in acid-free Hollinger box with a box content list and label printed on acid-free paper. This box was stored at PAL in accordance with state and federal curation guidelines until such time as a permanent repository is designated. PAL Report No. 2585 17 CHAPTER THREE ENVIRONMENTAL CONTEXT This chapter summarizes the geomorphology, surficial deposits, soils, hydrology, and existing conditions of the Madaket WWTF project area. An initial overview of Nantucket’s physiography is provided with project-specific detail, where applicable. The discussion of existing conditions within the project area was drawn from observations made by PAL archaeologists involved in the project. The Madaket WWTF project area is located at the western end of Nantucket Island, just east of Long Pond and closer to the south shore. The local topography is typical of the central outwash plains region, with characteristic flat terrain and little surface relief (see Figure 1-1). Glacial meltwater stream channels once crosscut the outwash plains in a north/south orientation. The southern extent of this valley is marked by a series of ponds, all of which were once elements of a complex Native American cultural landscape on Nantucket. In terms of surficial deposits, the project area is mapped as Nantucket younger outwash deposits with the stream channel itself marking a boundary with older outwash deposits (Oldale 1992:86). Geomorphology and Surficial Deposits Nantucket is the largest of four islands that combined measure 31,520 acres (49 square miles) and make up Nantucket County (Langlois 1979:1). Esther, Tuckernuck, and Muskeget islands trail off the western tip of Nantucket and are considerably smaller landforms. Nantucket lies approximately 25 miles south of Cape Cod’s southern shoreline. Along with Cape Cod, the Elizabeth Islands, and Martha’s Vineyard, Nantucket was created by geologic processes that occurred during the Pleistocene Epoch, between about 1.6 million and 10,000 years ago (Oldale 1992:183). Nantucket is situated within the Atlantic Coastal Plain physiographic province (Oldale 1992:3). The coastal plain margins generally correspond with the New England coastline to the north and the terminus of George’s Bank to the south. It includes the continental shelf in the areas presently known as Nantucket Sound, Vineyard Sound, and portions of the Gulf of Maine. The bedrock underlying Nantucket is composed of different kinds of consolidated sedimentary, igneous, and metamorphic rock buried by 1,500 to 1,800 feet of glacial deposits (Oldale 1992:19). Details about the bedrock composition are uncertain because very few geological borings have been taken. Overlying the bedrock are various sedimentary layers that accumulated during the Late Cretaceous (140 to 66 million years ago), Tertiary (66 to 1.6 million years ago), and Quaternary periods (1.6 million years ago to present). The Quaternary Period includes the Pleistocene Epoch, or great ice age, characterized by periods of glacial development interrupted by climatic warming trends and glacial recession. The modern configuration of Nantucket Island resulted from the effects of the Laurentide continental ice sheet and, after its deterioration, natural processes of erosion and deposition. Nantucket Island today consists mostly of coastal plain deposits buried by debris accumulated during the late Wisconsinan glaciation that began in Canada approximately 75,000 B.P. Glacial ice advanced across New England by 25,000 B.P. reaching the offshore islands by about 21,000 B.P. (Oldale 1992:95). The ice mass in this region was in the form of three abutting lobes: the Buzzard’s Bay Lobe to the west, the Cape Cod Lobe extending across central Cape Cod south to Nantucket and portions of Martha’s Vineyard, and the South Channel Lobe to the east including the Gulf of Maine (Figure 3-1). Terminal moraine deposits on Chapter Three 18 PAL Report No. 2585 Nantucket and Martha’s Vineyard mark locations of the Cape Cod Lobe glacial maximum. In simple terms, these are the unconsolidated particles of sand, gravel, silt, clay, boulders, and rock that built up as the ice sheet was melting at the same speed it was pushing forward. Terminal moraine deposits stretch from Chappaquiddick on Martha’s Vineyard east to Tuckernuck Island and along the northern part of Nantucket Island. Over most of Nantucket, the southern limit of the moraine is marked by ice contact slopes that drop down to a belt of low-lying swampland. This poorly drained region marks the front edge of the Cape Cod Lobe where it ceased advancing and separates the moraine deposits to the north from the outwash plains to the south. At this time, sea levels were approximately 300 feet lower than they are today. The continental shelf was an exposed landscape characterized by swamps, marshlands, and an abundance of plant and animal life (Oldale 1992:96). The Laurentide ice lobes retreated from the off-shore islands by 18,000 B.P. as the global climatic warming trend continued. All of New England was ice-free by 14,000 B.P. (Oldale 1992). As the recession continued northward across the mainland, meltwater streams springing from the ice front passed southwesterly toward the sea carving out channels and depositing a mixture of gravel, sand, and silt. These broad, flat, alluvial surfaces or outwash plains are the predominant glacial features on Nantucket (Oldale 1992:61). The project area intersects younger Nantucket outwash plains deposited over remnant ice blocks left behind during the glacial retreat (Oldale 1992:87). These deposits are described as sandy outwash with some gravel beds containing pebble to cobble size material and scattered boulders (Figure 3-2). Outwash deposits on this part of Nantucket also contain a few beds of silt and clay Figure 3-1. Ice lobes of the Wisconsinan glaciation and the formation of end moraines (source: Oldale 1992). Environmental Context PAL Report No. 2585 19 and occasional areas of fill. Moraine deposits marked by slightly more dramatic topographic features lie to the north of the project area from the Nantucket High School property west across Prospect Hill. The surficial deposits found on Nantucket were valuable resources for Native American groups, providing a lithic source for stone tool technologies and perhaps clay for making pottery. Archaeological studies have shown that Native Americans on Nantucket made most of their stone tools from glacially deposited cobbles available on the beach or by digging into moraine features. These deposits contain rocks carried south by the Laurentide ice sheet from the mainland bedrock. The most common rock types found in the drift include granite, volcanic rocks, basalt, and quartzite with some samples traceable to specific formations within the Massachusetts mainland (Oldale 1992:78–82). The range of source areas for the glacial till of Sankaty Head include volcanic rocks from near Boston [probably referring to Blue Hills, Lynn, and Mattapan complexes], sedimentary fossil-bearing sandstones from eastern Massachusetts and Rhode Island, pebbly conglomerate resembling that of southeastern Massachusetts, cretaceous sediments from the coastal plain including bits of lignite, and metamorphic rocks (gneisses and schists) like some of the rocks along the mainland’s coast from Newport eastward (Chamberlain 1964:144). Soils and Hydrology On Nantucket, soils have developed over the past 18,000 years since the retreat of the Wisconsin ice front (Oldale 1992:134). The major soil association within the project area is Riverhead sandy loam and Evesboro sand. These soils are usually found on gently undulating (0 to 3 percent slopes) and in nearly level areas. They are well-drained sandy soils formed on glacial outwash deposits. While these soils are well suited to use as building sites, they are poorly suited for farming, open land wildlife habitat, and woodland wildlife habitat (Langlois 1979:12). Figure 3-2. Geologic map of Nantucket Island showing the approximate location of the project area (source: Oldale 1992). Chapter Three 20 PAL Report No. 2585 Existing Conditions The area of the proposed Madaket WWTF is relatively flat to slightly undulating with low bush blueberry, scrub vegetation, and scattered pines (Figures 3-3 and 3-4). The two parcels for the infiltrators and the facility are intersected by Red Barn Road—a dirt road running northwest to southeast from the bridge over Long Pond. A dirt access also runs south off of Madaket Bridge Road through the proposed facility parcel. Figure 3-4. Photograph showing general project area conditions along dirt road in the facilities section of the project area, view northwest. Figure 3-3. Photograph showing general project area conditions on either side of Red Barn Road, view north northwest. PAL Report No. 2585 21 CHAPTER FOUR CULTURAL CONTEXT This chapter provides a synthesis of archaeological and historical data relevant to the pre-contact and post-contact human occupation of Nantucket. Research contexts pertaining to the Madaket WWTF project area draw in various degrees of the cultural chronology of the greater Northeast region, southern New England, the Cape and Islands region of Massachusetts, and Nantucket Island. For each recognized chronological subdivision within the pre-contact and post-contact periods, an overview of current knowledge and general developmental trends is provided. The pre-contact period cultural chronology establishes a set of expectations about the project area relative to Native American occupation from the PaleoIndian through the contact periods based on what is known about Native land on Nantucket Island, and in consideration of regional published data. The post-contact period cultural chronology does the same for Native American and Euro-American occupation and use of the project lands during and after contact. Pre-contact Period Nantucket Island was first explored by Native Americans approximately 11,000 to 12,000 years ago during the early Holocene PaleoIndian migration into the coastal Northeast. Archaeological remains from Nantucket illustrate a chronology of Native American land use that began soon after coastal deglaciation and continued through the nineteenth century. As in other parts of coastal southern New England, climatic fluctuations, sea level rise, and resulting ecological changes have influenced the capacity for human adaptation and settlement on this landscape since the PaleoIndian Period. From a modest peak on an extensive coastal plain to a relatively small and remote island, Nantucket’s environment has changed drastically since the Wisconsin glacial recession. Inundation of the coastal plain caused the formation of Nantucket, Vineyard, and Block Island sounds during the Early/Middle Archaic Period, as early as 8,000 years ago. Once cut off from the mainland, Nantucket’s proportions gradually diminished and it was not until the Early Woodland Period (ca. 2000 B.P.) that the island began to resemble its modern configuration (Oldale 1992:98). The following discussion provides a general overview of Nantucket pre-contact period from the PaleoIndian Period (12,000–10,000 B.P.) through the Late Woodland Period (1000–450 B.P.). Table 4-1 supplements the discussion with a chronological guideline of pre-contact temporal subdivisions correlated with changing cultural and technological developments over time. PaleoIndian Period (12,500–10,000 B.P.) Pre-contact human occupation on Nantucket began in the early Holocene Period ca. 12,000 to 10,000 years ago. During this time, Nantucket, Martha’s Vineyard, and Cape Cod were part of a continuous land mass. Archaeological evidence of PaleoIndian Period activity is limited throughout southern New England. However, an increasing number of PaleoIndian sites have been discovered and investigated in the southern New England region leading to a number of ideas about the settlement and subsistence patterns of these early groups. Most researchers have characterized PaleoIndian populations in the Northeast as highly mobile, small groups that explored and colonized the local area as resource-rich territories evolved from the postglacial landscape. Chapter Four 22 PAL Report No. 2585 Cultural Context PAL Report No. 2585 23 Most PaleoIndian sites are identified by the presence of fluted or lanceolate projectile points, exotic lithic materials, or assemblages that include gravers, scrapers, and channel flakes. On Nantucket, five fluted points have been inventoried in artifact collections, and one has been identified as a reworked Clovis point (Pretola and Little 1988). The MHC mentions the area of Coskata on the eastern shore of the Island as the site of a fluted point find (MHC 1987). On Surfside Road, a local collector found a quartz projectile point that appears to have been fluted and may date to the PaleoIndian Period. The specimen was reported by Dr. Elizabeth Little and its present location is unknown. Despite evidence that PaleoIndian groups were visiting Nantucket, there are no known sites that have undergone systematic excavations. Areas sensitive for PaleoIndian sites would include stable, postglacial landforms that have not been subject to coastal erosion and have access to sources of fresh water. Early Archaic Period (10,000–8000 B.P.) The discovery of Early Archaic tool forms and sites in a variety of environmental settings throughout the southern New England region indicates the development of a more broad-based subsistence pattern during this period. This phenomenon is presumed to have developed gradually as the postglacial boreal forest evolved into a mixed deciduous/coniferous forest. On Nantucket, the forest composition for this period was pine dominant with gradually increasing percentages of birch and oak (Dunwiddie 1990). Archaeological evidence on a regional scale indicates that Early Archaic groups probably had established territories that were much smaller than those exploited by PaleoIndian groups. Bifurcate-base projectile points are diagnostic artifacts of the Early Archaic Period, and assemblages may also include ground- stone tools, drills, anvil stones, choppers, and scrapers (Snow 1980:172). A few bifurcate-base projectile points have been discovered on Nantucket as evidenced in the NHA private collections inventories; however, contextual information is limited. Of the 644 projectile points analyzed during a 1978 site inventory sponsored by the NHA, only 8 percent were attributed to either the Early or Middle Archaic periods. A small concentration of Early Archaic points was collected from the northeast corner of the Island consistent with the trend for PaleoIndian and later Middle Archaic Period settlement. A lanceolate, “Dalton-like” projectile point found on a site bordering Foulger Creek has also been interpreted as evidence for Early Archaic activity (MHC site files). Otherwise, documented sites in the northern outwash plains region and in the project area vicinity do not appear to contain Early Archaic Period components. Since most site documentation on Nantucket has come from the 1978 inventory of large, private artifact collections, there is potential that early lithic materials could be overshadowed and possibly misidentified in these contexts. Given the suspected PaleoIndian find along Surfside Road, and the concentrated Late Archaic Period activity area in central interior Nantucket, Early Archaic sites could be expected within or near the project area. Middle Archaic Period (8000–6000 B.P.) Middle Archaic Period settlement patterns in the southern New England region suggest the development of localized group territories. When compared to the PaleoIndian and Early Archaic periods, Middle Archaic sites are found in a much wider range of environmental settings and contain evidence for an expanded resource base. During this period, inundation of coastal plain areas due to rising sea levels was ongoing, and both Vineyard and Nantucket Sounds were formed (Oldale 1986:100). Pine-oak and pine forests were well established on Nantucket, and some sections of the Island also supported a heathland vegetation type (Dunwiddie 1990). Known Middle Archaic sites on Nantucket have been discovered near freshwater ponds, wetland margins, and shoreline bluffs. Middle Archaic components mark some of the earliest occupations within several large multicomponent sites. The collections inventory appears to include a few Stark projectile points (based on site form sketches) diagnostic of the Middle Archaic Period from the Bartlett Farm Site (19-NT-102). Other Middle Archaic (Stark) or Early Woodland (Rossville) Period projectile points have been identified in the southern outwash plains region where a Chapter Four 24 PAL Report No. 2585 cluster of collector sites surrounding Great Mioxes Pond and the former Little Mioxes Pond have been identified (Sites 19-NT-11, 19-NT-12, and 19-NT-99). A quartz Snappit point, diagnostic of the late Middle Archaic Period, ca. 6000 to 5000 B.P. was recovered during a recent CRM survey for the Nobadeer Farm Road bike path (Doucette 2008a). The recovery of Middle Archaic tools has been documented elsewhere within the Nantucket outwash plains • in particular, on the margins of freshwater ponds. For example, diagnostic Neville and Stark projectile points have been collected by avocational archaeologists from sites in the western and southwestern section of Nantucket near Gibbs Pond and Tom Nevers Pond (19-NT-61). Similar finds have been recorded along interior ponds, creeks, and former pond locations now marked by wetlands. Like the intermittent finds dating to the PaleoIndian and Early Archaic periods, sites from the Middle Archaic Period appear to be associated with very specific microenvironmental settings on the Island. Late Archaic Period (6000–3000 B.P.) The Late Archaic Period may be better defined than previous periods because there is a significant increase in the numbers of known sites. This is due in large part to the diminishing rate of sea level rise during this period and the stabilization of coastal landforms. Late Archaic pre-contact sites have been identified in many different types of environmental settings across the Island including coastal, estuarine, and interior areas. Palynological research indicates that after about 5,500 years ago the vegetation on Nantucket consisted of a mixed hardwood forest with oak as the dominant species and some beech, tupelo, and maple. There was an increase in the variety of tree species on the Island, but forests appear to have been less diverse than those on the mainland of southeastern Massachusetts (Dunwiddie 1990). Stone tools diagnostic of the three major cultural traditions (Laurentian, Small Stemmed, Susquehanna) within the Late Archaic have been collected from sites across many sections of Nantucket. Projectile points attributed to the Laurentian tradition include Otter Creek, Vosburg, and Brewerton styles. Brewerton projectile points have been noted in artifact collections from Nantucket but do not appear to be widespread. Pretola and Little (1988:49) found that only 2 percent of the 644 projectile points identified by Dincauze in 1978 fell into the Brewerton classification and 11 percent were identified as either Small Stemmed or Squibnocket Triangle points. Recently, a chert Brewerton point (ca. 5000 to 4000 B.P.) was recovered in a fill context along Nobadeer Farm Road during a CRM survey for the Nobadeer Farm Recreation Center (Doucette 2008b). The Transitional Archaic Period dates from about 3800 B.P. to 2600 B.P., and important technological innovations include the manufacture and long-distance transport of steatite or soapstone vessels and probably some early forms of ceramic production. The exploitation of shellfish is likely to have begun during the period concurrent with the slowing of sea level rise and development of tidal flats and estuarine zones that provided a habitat for shellfish species. Cremation burial rituals are also a significant cultural aspect of the Transitional Archaic Period, as described below. The Transitional Archaic Cremation Burial District of Nantucket, ca. 3800–2600 B.P. The project area lies west of a zone of Native American archaeological sensitivity based on the documentation of six sites containing possible evidence of Transitional Archaic Period cremation burial practices. In 1978, Dr. Elizabeth Little participated in an effort sponsored by the NHA to inventory known sites on the island (Little 1983). Subsequently, she used the data to produce a predictive model for Native American archaeological sites that identified patterns in site and artifact types within four broad environmental zones. Zone 4 was referred to as “High Sandy Plain,” and was defined to include land lying above 33 feet above mean sea level on the northern half of the outwash plain as far east as Gibbs Pond (Little 1983:7). The six sites containing possible evidence of cremation burials were all located in Cultural Context PAL Report No. 2585 25 this environmental setting, and were concentrated in proximity to the Nantucket High School in the south- central section of the Island. Although there was no confirmation of human remains at these sites, the archaeological signature indicated by the presence of certain artifact types suggests that cremation burials once existed in these locations. Specific point types such as Mansion Inn, Orient, Coburn, and Hawes found in combination with steatite vessel fragments, calcined bone, and dense charcoal deposits are characteristic of cremation burial sites. In 1986, PAL was contracted to conduct an intensive archaeological survey on Nantucket Public School property in preparation for expansion of the high school and elementary school (Ritchie 1988). This was the first opportunity to test the predictive model proposed by Dr. Little with regard to the existence of a cremation burial district. In developing a research design for the project, Ritchie (1988:26) suggested that several identified sites may have been elements of one cremation cemetery. He further mapped a “cremation burial district” surrounding and including all of the discovered sites in the immediate vicinity of the high school property both above and below the 33 ft contour, but not including the entire High Sandy Plain zone identified by Little (1983). The southern boundary of the district extends as far south as Sewer Bed Road, encompassing the Miacomet burying ground. The 1986 survey at the high school did not locate any evidence of cremation burials, or other site types. This was attributed to the 1950s facility construction and the resulting alteration of the original landscape. To date, although Late and Transitional Archaic Period artifacts continue to be recovered in this area, confirmation of undisturbed cremation burials in either zone (Little 1983) or district (Ritchie 1989) has yet to be made. Of the original six sites that were considered to justify the cremation burial sensitivity zone, one (19-NT- 156) consists of a single complete Mansion Inn blade discovered in 1977 by a local artifact collector on a back dirt pile along Surfside Road. Although the state site form depicts a location for the find, it was estimated based on a local newspaper article that referred to a dirt pile, “. . . near the Thurston property” (MHC site files). The other five sites were all discovered to the north on private properties along Surfside Road or at the High School and Hospital properties. The Austin Site was identified from interviewing a resident of Surfside Road during a CRM survey. On the west side of Surfside Road opposite the Nantucket High School, excavations for a garage foundation on the Richard Austin property uncovered a charcoal-filled pit feature approximately 32 inches below the ground surface. Fragments of one or more steatite bowls, calcined bone, antler and shell, and a mixed assemblage of projectile points and bifacial tool blades were recovered. Five of the points were Coburn-like, side notched types of felsite comparable to those found on the high school property. Other diagnostic tools from the Austin property included an Early Woodland Period Meadowood point of chert, and three Small Stemmed points (Ritchie 1988:26). The charcoal feature description and contents represent the most compelling evidence suggestive of cremation practices on Nantucket. The other Transitional Archaic Period sites within this district consist of individual tool finds. For example, a large Atlantic projectile point was found in a disturbed context along Surfside Road. Another large projectile point of the Coburn/Hawes type was found in Wyers’ gravel pit along Surfside Road by a local collector, Nelson O. Dunham. This tool is currently in the archaeological collections of the NHA. Site 19-NT-85 located on the high school property consisted of Susquehanna tradition tools and steatite bowl fragments reported by a local collector (Roy 1956). During construction of the Nantucket Cottage Hospital on Prospect Street, another local collector reported finding steatite vessel fragments (MHC site form; 19-NT-93). In the absence of contextual data and archaeological records, little can be said about the meaning and significance of these individual tool discoveries other than that they are consistent with Native American activity during a broad period of time, the Late Archaic Period. Additional Late and Transitional Archaic Period tool types have been located throughout the central outwash plains as isolated finds and in association with small campsites and tool production or maintenance locations. Orient fishtail and Small Stemmed points are the most common among these, and Chapter Four 26 PAL Report No. 2585 have been discovered at the Nantucket Housing Authority Site on the opposite side of Miacomet Road (Carlson et al. 1992); at the proposed site of new high school staff housing to the north along First Way (PAL 2004); to the east at Nantucket Memorial Airport property (Willan and Ritchie 1995); at the proposed South Shore Links golf course (Rainey 2000); and southwest in Miacomet valley, on lands that were once considered for Miacomet Golf Course expansion (Rainey and Ritchie 1997). Late and Transitional Archaic diagnostic projectile points have also been found at many of the larger, multicomponent sites within the southern outwash plains generally on large pond or swamp margins. Interior settings for these settlement areas include Herrecater Swamp Site, Hummock Pond, and Gibbs Pond, all of which have been targeted by local artifact collectors and amateur archaeologists for at least 100 years. While these sites do not contribute to our understanding of Native American burial rites and traditions during the Late Archaic Period, they are evidence of a substantial community of island residents during that time. Early Woodland Period (3000–1600 B.P.) Following a pattern observed across other sections of coastal southern New England, Early Woodland sites on Nantucket contain some of the earliest evidence for the intensive use of shellfish resources. Settlement and resource procurement targeted the rich estuarine and salt marsh environments. In 1987 the MHC (1987:35) had on record 20 known sites on the Island with components attributed to the Early Woodland Period. Certain locations on the margins of larger, brackish wetlands and salt marshes with Early Woodland components continued to be used during the Middle and Late Woodland periods. A range of activities was staged from these sites such as shellfish collection and processing, marine and freshwater fishing, procurement of lithic raw materials, and deer hunting. Early Woodland sites on Nantucket often contain assemblages consisting of Meadowood, Lagoon, and Rossville type projectile points and thick, grit-tempered, cord-marked ceramics. During the Polpis Road data recovery program, similar lithic and ceramic types were found at two sites within coastal pond and marsh settings. At sites 19-NT-50 and 19-NT-68, there were Early Woodland components with numerous Rossville-like or untyped lanceolate points and bifacial preforms for similar projectile points. Ceramic sherds from thick-walled, cord-marked vessels tempered with crushed granite were also part of the assemblages. Recovered shellfish remains were primarily quahog; other food remains included deer, fish, and bird bone (Rainey 2004). Middle Woodland Period (1600–1000 B.P.) Sixteen sites dating to the Middle Woodland Period are listed in the MHC inventory of known sites for Nantucket. Middle Woodland Period settlement and resource exploitation was concentrated in the coastal zone near freshwater or brackish wetlands, streams, or salt marshes. Numerous locations in the coastal zone south of Nantucket Harbor were occupied with some of the sites containing evidence of intensive activity. Sites adjacent to the larger freshwater ponds on the western half of the Island were also occupied. For example, Middle Woodland components near Long Pond contain both shell midden and non-midden deposits. Locus Q-6 in the Quidnet section of the Island contained a Middle Woodland component radiocarbon dated to 1680 ± 80 and 1575 ± 160 B.P. This site and others in the coastal pond, and salt marsh and estuary zone contain evidence of intensive shellfish harvesting. At Locus Q-6, shellfish remains were primarily oyster most likely collected from Sesachacha Pond (Little 1984). At Site 19-NT-50 in the Sesachacha Pond area, a later Middle Woodland component contained small deposits of shellfish remains. A sample of oyster shell from one deposit was radiocarbon dated to 1290 ± 60 B.P. Activity areas within the site contained shellfish remains, bone fragments, and lithic workshops with dense deposits of chipping Cultural Context PAL Report No. 2585 27 debris. The lithic tool assemblage is dominated by lanceolate projectile points similar to the Greene and Fox Creek types and point preforms made of local felsites. Jack’s Reef Corner Notched points were a minority in the assemblage from 19-NT-50 and from other sites with Middle Woodland components (Rainey 2004). The occasional appearance on Middle Woodland sites of projectile points and bifacial tool blades made of cryptocrystalline lithic materials (chert, jasper) from sources outside southern New England indicates some participation in long-distance trading networks. On Nantucket, this pattern seems to be less prevalent than on the mainland of southeastern Massachusetts. Like the Early Woodland Period, there is little documented evidence of Middle Woodland Period activity in the immediate project area vicinity or in general throughout the central outwash plains region. The Creeks at the southern end of Nantucket Harbor and the northern reaches of Miacomet valley would be an expected setting for Woodland Period sites given the tidal estuarine environment. Late Woodland Period (1000–450 B.P.) Of the 644 projectile points identified in the 1978 NHA survey, 47 percent were Levanna types diagnostic of the Late Woodland Period. Based on variations in frequency among Early, Middle, and Late Woodland projectile point styles inventoried at that time, it was estimated that local Native American populations were steadily increasing in numbers throughout the Woodland Period and reached a peak by the Late Woodland (Pretola and Little 1988:49). The 1987 MHC inventory (MHC 1987:35) of known pre-contact sites on Nantucket does not reflect such a trend, showing a slight drop in the number of locations occupied in the Middle Woodland Period. Late Woodland Period settlement was concentrated in the coastal/estuarine zone in many of the same locations occupied by Early and Middle Woodland populations on the Island. A few large Woodland Period sites have been identified along the margins of the outwash plain ponds such as Long and Hummock ponds. Ram Pasture is one example of an extensive Late Woodland site. It appears to have functioned as a base camp in the Late Woodland Period about 1,100 to 500 years ago. Numerous Late Woodland projectile points as well as other tool types (drills, flake knives, hammerstones, ground stone axes) are indicative of a wide range of activities. Fragments of bone from various mammal (deer, fox, muskrat) and fish (tautog, sturgeon, shark) species indicate that both terrestrial and marine resources were elements of the pre-contact subsistence regime. While hunting and gathering was still an integral part of Native American life throughout the Woodland Period, horticulture or cultivation of domestic plants such as maize was probably established in the region by 1,000 years ago. Evidence for large-scale horticulture has yet to be discovered on Nantucket, however investigations of a large, Late Woodland pit feature at a site in Quaise was interpreted as possible evidence for storage of corn (Luedtke 1980:115). Ground-stone pestles have also been recovered on Late Woodland sites suggesting the processing of vegetal material, possibly of corn (Brooks 1942). Two of the Polpis Road data recovery excavations resulted in the recovery of substantial Levanna Point collections, Late Woodland radiocarbon dates, and small maize samples that span the Late Woodland to contact periods (Rainey 2004). Late Woodland components also often include both human and dog burials (Bullen and Brooks 1948; Trinkaus 1982; Turchon 1979). The Hughes Site, for example, on the east side of Long Pond contained three human burials found near a shell midden deposit. A single adult male, two children, and a dog were found in this multiple interment (Bullen and Brooks 1948). Late Woodland burials have not been discovered in the interior central region of Nantucket, although Ram Pasture may have contained a single burial. The Miacomet Burial Ground contains the remains of eighteenth-century Native Americans, Chapter Four 28 PAL Report No. 2585 although there was no evidence that the site was used for interment during the Late Woodland Period (Simon 1988). Contact Period (A.D. 1500–1620) The initial English claim to the Island of Nantucket, Massachusetts can be traced to the fifteenth-century voyages of John and Sebastian Cabot (1497–1498), who sailed under King Henry VII (Douglas-Lithgow 1911:5–6). It was not until 1659, however, that a permanent English settlement was initiated there, long after the colonial foothold on mainland territory had been established, and 17 years after settlement of Martha’s Vineyard. As a result, primary accounts describing the Island’s Native population prior to 1659 are virtually unknown with the exception of some obscure mainland reports. Although the Cabots did not land on Nantucket, the inhabitants of the Island were soon in contact with the sixteenth-century stream of traders, fisherman, and explorers who ventured into the waters off New England’s coastline seeking better fishing territories or new land claims. The English mariner Gosnold is said to have landed at Sankaty Head in the summer of 1602 (Douglas-Lithgow 1911:6), although most accounts indicate that he passed the Island and landed at Cuttyhunk. Both Captain Weymouth (1605) and Captain Dermer (1620) visited Nantucket, although no European settlements were established during this period (MHC 1987:56). While it is certain that explorers and fishermen were knowledgeable of Nantucket during the contact period, the lack of primary accounts may be attributed to the general difficulty these men may have had in reaching the shoreline (Byers 1987:18). To date, contact period archaeological sites on Nantucket are rare and are generally represented by small assemblages on Native American domestic sites that were established during the Woodland Period and occupied until the contact period, or were established during the contact period and remained in use into the eighteenth century. As such, material culture and specific Native American activities representing trade and exchange from off island European explorers and settlers prior to 1659 are often difficult to isolate and study. For example, the Polpis Road data recovery excavations at two traditional residential sites concluded that these home sites were occupied repeatedly for at least 3,000 years, yet were abandoned during the contact period. Traces of contact period cultural material were recovered from each site, and included seventeenth-century kaolin pipes, ballast flint flakes, radiocarbon-dated maize kernels, and early buff-bodied earthenware fragments (Rainey 2004). In contrast, site examination investigations at the Nantucket Golf Club project area identified one Native American site containing contact period artifacts such as a red clay pipe bowl fragment, as well as eighteenth-century European-made domestic wares, bottle glass, maize, beans, and faunal remains (Rainey and Ritchie 1996). The manufacturing date ranges for many classes of cultural material from this site spanned the contact period through eighteenth century, and were not spatially patterned. In this case, the site was interpreted as a residence established during the contact period and occupied well into the eighteenth century, a time of rapid change for Native Americans living on the islands off the Massachusetts coastline. Post-Contact Period The post-contact period context presented below includes a general overview of the processes that led up to an initial European settlement on Nantucket Island in 1659, and the progress of that community through the next several centuries. It is an abbreviated history developed by PAL as a result of CRM projects on the island. The historical context for Miacomet village is an evolving narrative as archaeological investigations continue to reveal new information about this community. Plantation Period (1620–1675) In 1621 Nantucket was included in the Royal Grant to Plymouth Company along with Cape Cod and Martha’s Vineyard (Douglas-Lithgow 1911:11). Management of this territory was the responsibility of Cultural Context PAL Report No. 2585 29 William Earl of Sterling and Sir Ferdinand Georges, the two principal Commissioners of the Plymouth Company in charge of promoting colonization. In 1641 James Forrett, acting as the New York agent to the Earl of Sterling, sold all the islands south of Cape Cod to the Medford merchant Thomas Mayhew (Worth 1992:6). This conveyance granted only the right to use the surface of the land (Worth 1992:7). It seems that Georges also held a royal grant to the Island, and Mayhew apparently secured title to the Island from him as well (Mooney and Sigourney 1980:12). In 1642 Mayhew acquired Martha’s Vineyard and the Elizabeth Islands, and he sent his son Thomas (age 26) to the Vineyard in the same year to begin a settlement (Goodwin 1879:538). The young Mayhew quickly learned the Algonquian language of the Native inhabitants and began the work of converting Native Americans to Christianity. By 1643 his Puritan missionary work on Martha’s Vineyard began to influence the Native population, and the religious ideologies were soon accepted. Thomas Mayhew Sr. joined his son in Edgartown in 1644 to propagate the work initiated by the younger. A permanent settlement on Nantucket had yet to be established, although the Mayhews made brief missionary visits to the Island during this early period (MHC 1987; Mooney and Sigourney 1980:13). Byers (1987:25) notes that the Mayhews and other Vineyard English families pastured sheep on the western end of Nantucket during this period and kept horses there for use during their periodic visits. Although the Mayhew family’s missionary efforts on Nantucket were well underway by the late 1640s, Native converts were soon used to facilitate the process (Byers 1987:27). This practice lessened the degree of direct contact between the Mayhews and Nantucket Native Americans, thereby reducing the frequency of recorded primary observations. Publications dating to this period of religious conversion offer the earliest insights into general aspects of the Island’s Native population, most of which reflect on the numbers of Native Americans converted, or the nature of Native American moral character. According to the extensive primary research conducted by Edward Byers (1987:18–19), “Not even the Mayhews of Martha’s Vineyard, who began missionary work on Nantucket in the late 1640s, left a record of Indian life.” In 1643, Thomas Mayhew Jr. converted the Native American Hiacoomes from Martha’s Vineyard, who then became partly responsible for the conversion of the Nantucket Indians. Daniel Gookin, supervisor of the English missionary effort, wrote in 1674 about Nantucket, “The first light of the gospel that came to this Island, was by means of Messr’s Thomas Mayhew, father and son; and also by Hiacoomes, now pastor of one of the churches upon that Vineyard” (Gookin 1806). Thomas Mayhew Jr’s missionary efforts were well known throughout England, and in 1656 he sailed for his homeland to gather additional support for the work. His ship never arrived, leaving the aging Thomas Mayhew Sr. to continue the missionary efforts (Goodwin 1879:538). In 1659 Mayhew sold the islands to a group of 10 investors, himself included, and in the next year a settlement was initiated on the west end of the island at Madaket. Tristram Coffin, one of the investors, traveled from Salisbury, Massachusetts in 1659 to assess conditions on the island and returned to Salisbury with favorable reports. He secured the services of Peter Folger of Martha’s Vineyard on that trip, Mayhew’s business agent and a fluent speaker of the Native language. As a result of the trip, a group of Salisbury residents, including Thomas Macy (Mayhew’s cousin), Edward Starbuck, James Coffin, Isaac Coleman, and several of their family members sailed to Nantucket to spend the winter of 1659–1660. In the next year, each of the original proprietors was permitted to name an associate, and the Island was divided into 20 shares. Before the legalities of the matter were settled, the number of shares was increased to 27, excluding the common land and land reserved for Thomas Mayhew (Douglas-Lithgow 1911:12). A list of the original 28 proprietors (Mayhew included) is presented in Barber’s 1839 sketch of Nantucket. The initial 1660 settlement was established in Sherburne—a high ground at Cappamet Harbor (Capaum), around the head of Hummock Pond and to the west of Reed Pond, where house lots were laid out (Forman 1966:22–23; MHC 1984b; Figure 4-1). The first gristmill was constructed on Wesko Pond in the 1660s to accommodate the processing of agricultural products (MHC 1984b). By 1671 the governor Chapter Four 30 PAL Report No. 2585 of New York granted a patent to the Nantucket proprietors, confirming their ownership and authority (Barber 1839:447). By the early 1670s, colonial interests turned to the potential benefits of the local fisheries to supplement the moderate productivity of the island meadows. The MHC (1984b) notes the beginnings of cod fishing and weir fishing industries during this period, with the participation of local Natives. In addition, Dr. Elizabeth Little and island resident, J. Clinton Andrews examined the Native tradition of drift whaling (meaning stranded alive or drifted ashore dead) on Nantucket as a precursor to the development of alongshore and pelagic whaling (Little and Andrews 1982). On Nantucket, compelling evidence of Native maritime aptitude rooted in tradition is found in seventeenth and early-eighteenth-century county records as well as Native legend. Like many other coastal New England groups, the Nantucket Indians valued the drift whale as a source of food, fuel, raw materials for tools, and as customary tribute in what Dr. Elizabeth Little refers to as a structured whaling industry (Little and Andrews 1982:17). Sachem rights to drift whales on Nantucket were retained until at least 1728, despite the widespread sale of land and other natural resources by sachems to the English settlers (Little and Andrews 1982). There is currently no documentary or archaeological evidence of a Native offshore whaling industry emanating from Nantucket during or prior to the contact period. The account of Captain George Weymouth who explored the region in 1605 describes in detail the Native Americans manner of killing whales from canoes using a bone harpoon tied to a rope (Rosier 1843). Weymouth’s journey reportedly included Nantucket, although there is yet no substantial proof of this. According to Little and Andrews (1982:19), the frequency of drift whales on Nantucket may have Figure 4-1. 1782 Map of Nantucket showing the approximate location of the project area (source: De Crevecoeur 1782). Cultural Context PAL Report No. 2585 31 eliminated the need to go hunt for them at sea. Data recovery investigations at Site 19-NT-68 along Polpis Road resulted in the collection of a substantial faunal assemblage from a residential site that was abandoned during the seventeenth century. Among the marine resources that may have been procured from a canoe by Native Americans during the Woodland Period are spiny dogfish, sturgeon, sea bass, striped bass, gray seal, and dusky shark. Alongshore whaling by the colonists began off the south shores of Nantucket after 1690. The Nantucket Indians’ involvement in the development of the industry has been well documented: “given the supply of right whales close to shore, and a labor pool of Native Americans with a maritime aptitude as well as an interest in drift whales, we can readily understand the successful European introduction of alongshore whaling to southeastern New England and eastern Long Island” (Little and Andrews 1982:29). The success of the pelagic whale fishery, according to de Crevecoeur (1971:116), “. . . grew out of the success of the alongshore whale fishery.” As the industry grew, whaling and codfish stations were established in Siasconset, Polpis Harbor, Quidnet, and Great Point, and the road network expanded to link these areas to the main harbor. Alongshore whaling expeditions usually lasted one to two weeks. The English ship owners employed Native Americans for crew and paid them with a stipulated portion of oil (Starbuck 1989). The lowest positions of the labor force were filled by the Native Americans, in many cases as a result of debts incurred through the purchase of alcohol from the colonists (Byers 1987:6–7). In 1687 the expanding village was incorporated as the town of Sherburne. Nantucket was transferred from New York to Massachusetts’s jurisdiction through a 1692 act of Parliament, and in 1695 it became a county (MHC 1984b). By the early 1700s, Nantucket had taken the lead in the system of boat-whaling from the shore, which involved the construction of lookout stations (called spars) at prominent points along the coast from which sightings were reported. The whale-boat crews were quartered in small huts near the spars, and the lookout man would alert them when whales were spotted. The harpooner and one or two other members of each crew were Native Americans. It was soon recognized that the deep-water sperm whales produced oil of a much finer quality than that of the right whales, which were pursued alongshore. New technologies were designed for the necessities of offshore whaling, including larger and faster boats, new and better gear, and on-board processing systems. Nantucket whalers enthusiastically moved into the new era, and by 1715, six sloops were making voyages of several weeks duration, sometimes as far as the waters off Newfoundland (Hohman 1928:27). The development of the present downtown area was directly related to the growth of the whaling industry. In 1678, the Wescoe Acre Lots were laid out, initiating a gradual shift in the population core from the original Sherburne location at Capaum to the sheltered area along Nantucket Harbor (see Figure 4-1). Prior to 1717, development in this area was restricted to a few homes not necessarily within the bounds of the Wescoe lots. By 1717, a series of storms resulted in the transformation of Capammet Harbor into an enclosed pond (Worth 1992:203). With the whaling industry fast becoming the Island’s economic mainstay, a population migration to the large and protected Great Harbor area was eminent. In 1717, a second division of land adjacent to the Great Harbor called the Fish Lots was set off to include 27 equal parcels, one for each Proprietor. By 1720, the community was officially relocated to Nantucket Harbor (Lang and Stout 1995:26). Through the eighteenth and nineteenth centuries, the sequence of lot divisions reflects the rapid expansion of the downtown community in response to a successful local whaling industry. Native American Land Use and Settlement Patterns of the Miacomet Indian Village ca. A.D. 1693–1800 A review of past and ongoing research into the history of Miacomet Indian Village is providing new insights into the span of its existence, its location within the Miacomet valley, the nature of community Chapter Four 32 PAL Report No. 2585 structure, and the larger social context of its residents. A comprehensive consideration of the documentary record of this settlement, including ethnohistoric accounts, descriptions in secondary histories, and the manuscripts prepared by Dr. Little, reveals a marginalized community that formed out of necessity, remained autonomous through part of the eighteenth century, and was quickly forgotten by the early nineteenth century, less than 50 years after the devastating epidemic of 1763–1764. The following discussion begins with an overview of primary records that support Miacomet Village as a late-eighteenth-century development rather than a traditional, pre-contact period settlement territory. This is followed by an assessment of Dr. Little’s manuscripts on Indian Houses (1981) and the History of Miacomet Village (1988a), which chronicle the span of the village and it’s associated meetinghouse, identifies residents who she believed owned wood-framed houses, and proposes a community layout. The analysis was in part an outcome of a recent study in the upper Miacomet valley that resulted in the discovery of a longhouse and wigwam feature complex, interpreted as the possible site of the Miacomet meetinghouse (PAL 2004). The assessment calls into question the proposition by Little and others that the Miacomet meetinghouse was built of wood, and that its construction coincided with the arrival of Minister Timothy White. Because there is an extant sketch map produced by Dr. Little that links individual Native Americans with specific property locations, it is essential that the path of her reasoning in these documents is addressed. Information about each of the Miacomet residents named by Dr. Little is also provided (1988a:12). Initial Settlement of Miacomet, 1674–1694 There are no historic references to Miacomet as a community or a Christian Indian village during the era immediately following the initial English settlement in 1659. Most descriptions of Nantucket’s Native population in the seventeenth century refer to the existence of four main settlement areas, or villages, when Mayhew’s group arrived in 1659 (Gookin 1806; Macy 1972; Starbuck 1924; Worth 1992). This is based on the recognition of four sachems from whom the English were negotiating with immediately upon occupation of the island. The largest territories in the eastern part of the island were under the leadership of Wanachmamak and Nickornoose, and the two smaller territories were led by Attapeat (also called Autopscott) and Spotso. Although Wanachmamak and Nickornoose did not live in the west end, the first 1659 land transfer of the West End to Mayhew was from these two important sachems (Figure 4- 2). Wanachmamak also participated in many other transactions to the English conveying territory under the authority of less-powerful sachems, particularly in the western end where the English initially settled. In 1660, Wanachmamak conveyed to the proprietors land in the west end of Nantucket, the winter seed of the entire Island from the end of Native American harvest until planting time, liberty to take wood and timber throughout the island, and half of the meadows and marshes (Worth 1992:113–115). In the first decade of English occupation, a rapid succession of similar agreements followed, resulting in the depletion of Native held territory, and the cultivation of internal conflict among the various sachemships. It is unclear why Wanachmamak so willingly inspired the practice of selling the Islands’ natural resources, critical elements of Native subsistence at the time. His generous exercise of authority in these matters may have been designed to protect his traditional homeland, known historically as Occawa, through an uncertain future beyond his imminent death. By 1684 there appears to be five main sachemships on Nantucket, three of whom had some jurisdiction over central and western territory (Little 1996:194). They were Seiknout (Muskeget Island), Pattacohonet (Tuckernuck Island), and Attapeat (central interior lands). In terms of Native settlement patterns, the late seventeenth century writings of Daniel Gookin provide the earliest characterization of the Island’s “praying Indians” (Gookin 1806). Based on Gookin’s discussions with Nantucket Indians who had become Christian ministers, including John Gibbs and Caleb, in 1674 he writes: Cultural Context PAL Report No. 2585 33 there is one church at Nantucket, whereof John Gibbs aforesaid is pastor: that there is about thirty men and women in full communion in the church, whereof twenty are men: that there is about forty children and youths baptized: and that there is about three hundred Indians, young and old, who pray to God and keep the sabbath upon that island: that they meet to worship God at three places: viz. Oggawame where the church meets, at Wammasquid, and Squatesit: that there are four Indian teachers upon that island, viz. John Gibbs, pastor, Joseph, Samuel, and Caleb, who also teacheth school (Gookin 1806). In the same passage, he relates a section of a letter from a “Mr. Cotton” dated September 1674: at Nantucket, according to my best intelligence, there are three praying towns; and praying Indians, about three hundred males and females; one church, the pastor is John Gibbs; the men in church fellowship are about twenty; the women, ten. Their children are all baptized. The English upon that island, who are about twenty seven families, and many of them Anabaptists, did as first seek to hinder them from administering baptism to infants; but now they are quiet, and meddle not with them. Caleb is preacher to one town there. None of the three places mentioned by Gookin clearly correspond with Miacomet. Worth (1992:293) indicates that the word Miacomet derived from the Algonquian word “maayeakomuk” meaning “the Meeting House,” although the source of that information is not given. A postscript in Gookin’s Historic Collections states that by 1694, there were about 500 adult Indians on Nantucket, five assemblies of praying Indians, and three churches (John Gardner’s 1694 letter in Gookin 1806). The documentary evidence indicates that between 1674 and 1694, the number of Christian Indian communities (assemblies) Figure 4-2. Territories of major sachems at Nantucket and Tuckernuck in the late seventeenth century (source: Little 1988a:3, Figure 2). Chapter Four 34 PAL Report No. 2585 increased from three to five, while there were still only three Indian churches. It is likely then, that Miacomet evolved as a new residential Indian community within that 20-year span. Genealogical links established by Little (1988a:9) between descendants of Attapeat and eighteenth-century Miacomet Indian ministers were in her view support for the existence of Miacomet as one of the five assemblies mentioned in Gardner’s 1694 letter (Little 1988b:9). In 1700 there were an estimated 800 Native Americans remaining on Nantucket (Byers 1987:27). Despite an influx of Native American whalers and laborers in the 1740s, by the mid-eighteenth century most of the remaining Native American lands were sold to the English, and the Native population continued to decline. A series of eighteenth-century court records printed in Starbuck (1924:163–169) documents a succession of Native American/English disputes from remnant settlement areas across the central and eastern sections of the island through the mid-eighteenth century. Although it is clear that some of the Native Americans garnered financial success as part of the burgeoning whaling industry, they appear to be those with the closest genealogical links to important seventeenth-century sachems who initiated the disposal of Native held territory and resources (Little 1996). In 1763 a plague spread through the Native community, killing 222 of the 358 surviving Native Americans on the Island (Little 1988b). It is uncertain how long Native Americans may have continued to live in this area after the epidemic, although early-nineteenth-century maps indicate that much of the land bordering the east side of Miacomet Pond was taken over for Sheep Pens (Ewer 1869; Figure 4-3) De Crevecoeur (1971:123) acknowledged a Native American community living in decent houses along Miacomet Pond in 1782, while the Reverend Freeman referred to Miacomet as a former Native American village 25 years later (Freeman 1815). According to one secondary account, only four male Native Americans and 16 females were left on Nantucket in 1791, and by 1809 there remained only three or four persons of pure Native American blood (Douglas-Lithgow 1911:29). If the estimates are correct (Macy 1972:57), the large relative proportion of Native deaths in 1763–1764 (62 percent of the island’s total Native population) would have accelerated the demise of any remaining community structure in Miacomet and elsewhere on Nantucket where settlements and meetinghouses once existed. Thus it appears that by the last decade of the century, Miacomet appears to have dissolved as a community. Three twentieth-century references found in the Nantucket Historical Commission manuscript collections (Grace Brown Gardner’s Collection 57, Scrapbook 20) indicate that the last wigwams standing on the island were in Squam, and were removed by the last decade of the eighteenth century. Federal Period (1775–1830) During the Revolutionary War, the English residents of Nantucket chose a position of neutrality because of their exposed and indefensible position at sea, and also as a result of the beliefs of its large population of Quakers. Despite the fact that neither the British nor the Americans would recognize their position, they continued to send out ships on whaling expeditions. The repeated capture and plundering of the island’s vessels during the war resulted in great losses to the community. In 1784, only 28 whalers were left, many of which had been repaired. Approximately 1,200 Nantucket seamen had been lost and captured, and more than 200 women found themselves newly widowed (Hohman 1928:35). This period was marked by economic depression and the emigration of a number of the island’s inhabitants. The demand for sperm candles in American as well as in foreign markets brought renewed short-lived prosperity in the 1790s. The War of 1812 created a similar phenomenon of commercial ruin, with a second rebound after the war’s end. Cultural Context PAL Report No. 2585 35 It was during this time that the sheep-raising industry, largely focused in the outwash plains region, began to develop an increasing significance in the island economy (Figure 4-4). A succession of annual events evolved including the driving of flocks prior to shearing events, the actual shearing, and community social events following the tradition (Marshall 1962:15). In order to regulate the use of common land by sheep owners, the Nantucket proprietors translated each persons share of common land into a specific number of “sheep commons.” It was estimated that an acre of common land would maintain one sheep (Worth 1992:198). In the early eighteenth century, the survey of the land held in common was calculated at 19,440 acres, the equivalent of the number of sheep that could be pastured. A “sheep common” meant the right to pasture one sheep, or 1/19440 of the common land. Originally, the island common land was held in 27 shares, which is the number of original Nantucket proprietors. As time passed, the shares were subdivided into very small fractions as families grew (Worth 1992:198–200). The concept of owning a right or percentage of a right to pasture an animal on a large area of land created a variety of problems during the nineteenth and twentieth centuries. In the early nineteenth century, a lawsuit brought by the Mitchell family demanded that a tangible tract of land with recorded boundaries be conveyed for their shares of sheep commons. They owned a sizeable territory in the eastern section of the island called Plainfield, the former setting of Occawa Village. Figure 4-3. 1776 map of Nantucket showing the approximate location of the project area (source: DesBarres 1776). Chapter Four 36 PAL Report No. 2585 A decision by the Supreme Court in 1815 allowed for a man owning 100 sheep commons to sell his commons for a defined piece of land, thereby giving up any future rights to common lands (Worth 1992:210). The new practice required that the proprietors conduct formal surveys, and that all of the common land be surveyed and set off in the records. In 1821, the proprietors voted to lay out into 27 shares all of the common and undivided land on the island excluding the South Pasture (Nantucket County Records: Proprietors Book 1:50). According to DeYoung (1984:2), many people obtained common land set offs in exchange for their sheep commons within South Pasture excluding tracts adjacent to Miacomet Pond. In 1822, a large sheer pen pasture was established east of the pond, which is depicted on a number of historical maps. DeYoung found evidence to suggest that this land was at one point to be set off in severalty to a group of influential proprietors. This apparently never transpired. In addition, the lot containing the Miacomet burial ground and adjacent lot to the south was never laid out and remained common land until the 1980s. Early and Late Industrial Periods (1830–1915) This general period in Nantucket’s history was marked by a peak in population and prosperity from maritime activities, followed by a decline in growth within these areas. In 1840, Nantucket’s population reached 9,012 (MHC 1987:114). During this time, 64.7 percent of Nantucket’s economic prosperity was derived from maritime activities, with agricultural pursuits totaling only 4.7 percent (MHC 1987:116– 117). The gradual decline in maritime trade led to a high unemployment rate and a loss of population from 9,012 in 1840 to 4,123 in 1870 (MHC 1987:114). Residents left the island for more prosperous, industrialized population centers on the mainland. The California Gold Rush of 1849 also drew hundreds Figure 4-4. 1869 map of Nantucket showing the approximate location of the project area (source: Ewer 1869). Cultural Context PAL Report No. 2585 37 of unemployed island residents. Residential and commercial development in downtown Nantucket, which had continued since the Federal Period, came to a halt in 1850. The maritime economy of Nantucket suffered in part because of its dependence on the mainland for food and manufactured items that could not be locally produced. Between 1840 and 1870 the economic base provided by agricultural pursuits nearly equaled that of maritime efforts (MHC 1987:117). Residents began to grow their own food, and much of the vast, open land on the island was utilized as pasture for grazing livestock. Small, local, short-term manufacturing enterprises also developed at this time, producing commodities such as hosiery, straw goods, and shoes. In the 1850s, there were more than 100 farms on Nantucket (Gardner and Gibbs 1947) (Figure 4-5). In 1856, the Nantucket Agricultural Society was formed by local residents with the intent of educating island farmers, and fostering community cohesion, prosperity, and pride (Newell 2001:2). Land adjacent to Fairgrounds Road was purchased for the annual fair, which grew into a three-day event featuring cattle and oxen shows, fruit and vegetable displays, an arts and crafts show, and entertainment. The Nantucket Agricultural Society realized the potential for the fair to draw tourists to Nantucket and revitalize the local economy, and began advertising the event on the mainland (Newell 2001). Toward the end of the nineteenth century, a focus on island-based activities emerged with new improvements in overland transportation. Tourism became important to the local economy, and hotels, cottage colonies, and summer estate districts sprang up around the central village, and in several outlying areas of the island. A trolley also served these summer resort populations during this period (MHC 1987). The growth in tourism drew labor away from agricultural enterprises across the island, and ultimately contributed to the demise of the Agricultural Society. Despite the growing decline in Figure 4-5. Map of Nantucket showing the location and ownership of farms in 1850 (source: Gardner and Gibbs 1946). Chapter Four 38 PAL Report No. 2585 attendance, the society held their annual fairs through 1939. In 1879, a group of Boston-based investors joined together to promote the design and construction of the Nantucket Railroad (Figure 4-6). The idea was to provide passenger service to a growing summer community of tourists, while promoting their own land sales. In 1881, the initial segment from Nantucket Village to Surfside was complete and running. A second section connecting a resort hotel at Surfside to Siasconset along the southern coastline was completed in 1884. This route was abandoned in 1894 because of coastal erosion, forcing the Nantucket Railroad company into foreclosure. The succeeding Nantucket Central Railroad company built a new rail line to Siasconset, which ran intermittently under various owners until the onset of the First World War in 1917 (Karr 1995). Modern Period (1915–Present) The advent of tourism as a new industry on Nantucket in the late nineteenth century was promoted by improvements to the harbor and existing transportation systems (ferry service) connecting Nantucket with the mainland. Island resort centers grew, and the population of Nantucket increased slightly during this period. Although the automobile was introduced to the island in 1900, residents succeeded in prohibiting summer auto traffic in the downtown area through a state law that lasted from 1906 to 1918. The most significant change of the era in the central interior section of the island was the development of the Nantucket Airport. The airport property was part of a larger tract of farmland owned by Leslie Holmes Figure 4-6 1887 USGS map of Nantucket showing the approximate location of the project area (source: USGS 1901). Cultural Context PAL Report No. 2585 39 (or Holms) during the years prior to World War II. At that time, Mr. Holmes decided to allocate part of his farm to build a small landing field. Small dirt landing strips, a hanger, and an administrative building were established. At the outbreak of World War II, the town purchased the land for use as a training base by the Navy. Some antisubmarine patrol reconnaissance flights were also initiated from the site. Improvements to runways and construction of additional facilities were undertaken by the Navy. In 1946, the airport was turned over to the Town of Nantucket. 40 PAL Report No. 2585 CHAPTER FIVE RESULTS, INTERPRETATIONS, AND RECOMMENDATIONS Results This chapter presents the results of the intensive (locational) survey conducted within the Madaket WWTF project area, and the interpretations and management recommendations based on these findings. Following the completion of archival research, the fieldwork aspect of the survey included a walkover inspection of the project area and subsurface testing. Subsurface testing focused on those sections of the project area considered to have high and moderate archaeological sensitivity. Archival Research The archival research carried out for the Madaket WWTF project resulted in the collection of information about known archaeological and cultural resources in the central outwash plains area of Nantucket and the surrounding vicinity. A review of the MHC site files indicates that there are more than two dozen previously recorded Native American archaeological sites located within one and a half miles (2.4 kilometers) of the project area spanning back at least 5000 years. At the Hughes Site (19-NT-92), located just north of the project area, on the east side of Long Pond, three human burials were found in the 1940s dating to the Late Woodland Period (ca. 1000 to 450 years ago). Other Woodland Period sites nearby include the Madaket Dump (19- NT-32), the PCM-15 Site (19-NT-36), and the Dunham and Brooks Site (19-NT-103), which yielded evidence of Late Archaic through Contact Period occupation. Given the location of known sites in the vicinity, undisturbed sections of the project area were considered to be archaeologically sensitive, exhibiting environmental characteristics favorable for ancient and historic period land use and occupation. Based on the frequency and temporal range of pre-contact sites surrounding the project area, potential pre-contact site types that could be expected within the Madaket WWTF project area could range from find spots of single artifacts and small temporary camps to larger multi-component sites dating from the Middle Archaic Period through the Late Woodland Periods, and possibly into the Contact Period. The historic period archaeological sensitivity of the project area is based on the previously identified eighteenth-century historic Native American settlement of Miacomet on the island. Activities associated with the community may have continued until 1782, when the meetinghouse was finally removed. Eighteenth century Native American houses adapted from the pre-contact period wigwam style were most likely constructed on the ground surface, and could be identified archaeologically based on assemblages found at other historic Native American house sites on Nantucket (Rainey and Ritchie 1996). Archaeological evidence of later historic period sheep raising activity is also possible. Records indicate that the first Quaker Burial Ground was located near the south end of Maxcey’s Pond between 1711 and 1760. The Quaker Cemetery at the corner of Madaket and Quaker Roads, was established in 1730. The project area also lies approximately .8 miles (1.3 km) southwest of the Madaket Ditch, a canal dug around 1665 by both English settlers and Native Americans connecting Long Pond to Madaket Harbor. The ditch was used to hold a fish weir that was especially good for catching herring (http://yesterdaysisland.com/madaket-ditch-hither-creek-and-millie/). Results, Interpretataions, and Recommendations PAL Report No. 2585 41 Results of the Field Investigations Based on a walkover inspection, the majority of the project area was considered to have high archaeological sensitivity and does not appear to have been disturbed in recent times by human activity. A total of 124 test pits was excavated within the proposed infiltrator and facilities parcels of the Madaket WWTF project area (Figure 5-1). These test pits, 50-x-50 cm in size, were excavated along eight linear transects (Transect A-Transect H). There was no pre-contact material or features recovered within the project area. A low density of post-contact cultural material was recovered in two of the 124 test pits and from the ground surface near one of those pits (TB-15). Subsurface testing documented undisturbed soil horizons over the majority of the project area. Soil profiles were generally consistent throughout the project area. A typical profile included a 6-cm Ao horizon overlying dark brown silty fine sand plowzone/Apz extending down to an average depth of 22 centimeters below surface (cmbs), which overlay a dark yellow-brown silty sand B1 subsoil to 40 cmbs and a yellow-brown sand B2 down to approximately 62 cmbs. A light yellow-brown sand C horizon was exposed under B2. The extent of excavation was approximately 75 cmbs (Figures 5-2 and 5-3). No cultural features were identified on the basis of soil color or texture. A total of 42 artifacts was recovered during the intensive survey (Appendix A). A range of domestic post- contact cultural material was identified including ceramic sherds, nails, shell, white-clay smoking pipe fragments, clam shell, and burned bone (Table 5-1). The cultural material came from fill contexts or from the ground surface, and while it includes some early post-contact materials such as ceramics (e.g., redware, pearlware), hand-made brick, and white-clay pipe bowl fragments, there were also more recent finds such as wire nails and machine made clear bottle glass. The fill and surface contexts in which this material was recovered suggest that the deposits were likely redeposited, potentially during the construction of an unnamed dirt road running through the facilities parcel. Table 5-1. Cultural Material Recovered from the Madaket WWTF Project, Intensive Survey. Bivalve Bottle/ Jar Brick Ceramic Sherd Clinker/ Coal Hollo -ware Nail Smoking Pipe Mammal Bone Total Ball Clay 2 2 Calcined Bone 1 1 Clinker 1 1 Coarse Earthenware 2 2 Earthenware 9 9 Ferrous 3 3 Glass 1 1 Porcelain 1 1 Refined Earthenware 19 1 20 Shell 2 2 Total 2 1 9 19 1 4 3 2 1 42 Chapter Five 42 PAL Report No. 2585 The majority of the diagnostic material consists of ceramics with date ranges falling between 1600 and present; beginning dates range between 1600 and 1934 and terminal dates range between 1890 and present. The older assemblage of ceramics includes lead glazed redware, creamware, and hand painted and shell-edged pearlware, and the later ceramic assemblage includes two fragments of whiteware. Interpretations and Recommendations Archival research conducted for the intensive (locational) archaeological survey of Madaket WWTF project area reviewed information about patterns of Native American and Euro-American settlement/land use in the general vicinity of the project area. The scope of archival research included the island of Nantucket, especially sites identified within and near the project area. Information reviewed at these different scales was used to predict the types of archaeological sites that might be present. Archival research indicated that the project area had a strong potential to contain pre- and post-contact Native American archaeological sites given the reported presence of several sites adjacent to the project area, and the dozens of sites located on Nantucket in similar environmental contexts. The goal of the intensive survey was to determine the absence or presence of potentially significant archaeological sites. PAL personnel conducted extensive subsurface testing within the project area based on the results of the walkover survey and sensitivity ranking. Subsurface testing with 124, 50-x-50-cm test pits documented undisturbed and disturbed soil horizons within the project area, relatively little cultural material, and no subsurface or above ground features. The generally diffuse distribution of the cultural material assemblage from road fill contexts combined with the lack of any associated structural, landscape, or household features suggests that it is best characterized as yard/field scatter with no locational or associative integrity. Fill deposits in the project area contained a mixture of recent and historic cultural materials, demonstrating that the deposits are more recent. Analysis of the soil profiles and cultural material suggests that these fill deposits are likely related to road construction as well as more isolated utility installations, driveway construction, and landscaping events associated with an abandoned Federal Aviation Administration building within the larger 92-acre parcel, but outside the project area. The project vicinity was characterized by scattered farmsteads through the nineteenth century, until summer communities were established beginning in the twentieth century. While the cultural materials recovered from the project area are evocative of the early post-contact period use of this portion of Nantucket Island, the materials do not constitute potentially significant cultural resources. Both the fill and surface scatter contexts suggest that the deposits have a limited potential to provide new or substantive information about the history of the area, and as such do not constitute potentially significant archeological resources. Recommendations Based on the results of this survey, the proposed construction within the Madaket WWTF project area will not impact any potentially significant archaeological resources. No further archaeological investigations are recommended. Results, Interpretataions, and Recommendations PAL Report No. 2585 43-44 Figure 5-1. Location of intensive survey testing within the Madaket Waste Water Treatment Facility project area. Results, Interpretataions, and Recommendations PAL Report No. 2585 45 Figure 5-2. Representative soil profiles within the Madaket Waste Water Treatment Facility project area. Chapter Five 46 PAL Report No. 2585 Figure 5-3. Photograph showing test pit 19 along Transect F (TF-19) and general soil profile, view east. PAL Report No. 2585 47 REFERENCES Barber, John Warner 1839 Historical Collections Relating to the History and Antiquities of Every Town in Massachusetts. Dorr, Howland and Company, Worcester, MA. Bragdon, Kathleen J. 1996 Native Peoples of Southern New England, 1500-1650. University of Oklahoma Press, Norman, OK. Brooks, Edward 1942 Progress Report on Site M-52-3, Nantucket, Massachusetts. Bulletin of the Massachusetts Archaeological Society 3(3):34–35. Bullen, Ripley, and Edward Brooks 1948 Three Burials at the Hughes Site, Nantucket, Massachusetts. Bulletin of the Massachusetts Archaeological Society 10(1):14–15. Byers, Edward 1987 The Nation of Nantucket: Society and Politics in an Early American Commercial Center, 1660-1820. Northeastern University Press, Boston, MA. Carlson, Catherine, Elizabeth Little, Richard Gumaer, Leonard Loparto, and Brenda Baker 1992 Archaeological Survey and Historical Background Research for the Miacomet Indian Village and Burial Ground, Nantucket, Massachusetts. UMass Archaeological Services. University of Massachusetts, Amherst, MA. Chamberlain, Barbara Blau 1964 These Fragile Outposts: A Geologic Look at Cape Cod, Martha's Vineyard, and Nantucket. Parnassus Imprints, Yarmouth Port, MA. Cherau, Suzanne Glover 2001 Native Building Traditions in Southern New England: A Study of the Aquinnah Wampanoag Community, Martha’s Vineyard. Paper presented at the 2001 Annual Meeting and Conference, Vernacular Architecture Forum, Mashantucket Pequot Museum and Research Center, Mashantucket, CT. de Crevecoeur, Hector St. Jean 1782 Map of the Island of Nantucket. 1971 [1782] Letters from an American Farmer. Reprint. Everyman's Library, New York, NY. DesBarres, J.F.W. 1776 Map of Nantucket Island, Massachusetts. References 48 PAL Report No. 2585 DeYoung, Stephen 1984 Report to the Town on Map 67, Parcel 82. Manuscript on file at the Massachusetts Historical Commission, Boston, MA. Dincauze, Dena F. 1974 An Introduction to the Archaeology of the Greater Boston Area. Archaeology of Eastern North America 2(1):39–67. Donta, Christopher L., and Mitchell T. Mulholland 1994 Archaeological Site Examination of Parcel B, Nantucket Housing Authority, Nantucket, Massachusetts. Report on file at Massachusetts Historical Commission, Boston, MA. Doucette, Dianna L. 2007 Intensive (Locational) Archaeological Survey, Ellen’s Way Subdivision Project Area. PAL Report No. 2105. Submitted to Blufin Partners, LLC, Nantucket, MA. 2008a Intensive (Locational) Archaeological Survey, Nobadeer Recreation Facility Project Area, Nantucket, Massachusetts. PAL Report No. 2252. Submitted to Avalon Consulting Group, LLC, Taunton, MA. 2008b Intensive (Locational) Archaeological Survey, MassHighway Assignment 43, Nobadeer Farm Road Bike Path Project Area, Nantucket, Massachusetts. PAL Report No. 2226. Submitted to Massachusetts Highway Department, Boston, MA. 2009 Intensive (Locational) Archaeological Survey, Quaker Road Bike Path Project Area, Nantucket, Massachusetts. PAL Report No. 2279. Submitted to Town of Nantucket, Nantucket, MA. Doucette, Dianna L. and Nichole Gillis 2010 Intensive (Locational) Survey of the Cliff Road Multiuse Path Extension Project Area, Mass DOT Assignment #10, Nantucket, Massachusetts. PAL Report No. 2423. Submitted to Massachusetts Department of Transportation, Highway Division, Boston, Massachusetts. Doughton, Thomas L. 1997 Unseen Neighbors: Native Americans of Central Massachusetts, A People Who Had “Vanished” in After King Philip’s War: Presence and Persistence in Indian New England. Colin G. Calloway, editor, p. 207–230. University Press of New England, Hanover, NH. 1999 “Like Shadows in the Stream” Local Historians, The Discourse of Disappearance and the Nipmuc Indians of Central Massachusetts. Retrieved April 10, 2003 from http://geocities.com/quinnips/history/shadowstreams.html. Douglas-Lithgow, R.A. 1911 The Nantucket Indians. The Inquirer and Mirror Press, Nantucket, MA. Dunwiddie, Peter W. 1990 Postglacial Vegetation History of Coastal Islands in Southeastern New England. National Geographic Research 6(2):178–195. References PAL Report No. 2585 49 Elquist, Ora, and Dianna L. Doucette 2007 Intensive (Locational) Archaeological Survey, 2 Fairgrounds Road, Nantucket, Massachusetts. PAL Report No. 2016. Submitted to Town of Nantucket, Nantucket, MA. Ewer, Rev. F.C. 1869 Historical Map of Nantucket. Reproduced in 1974 by E. & E. Williams Jr. Forman, Henry Chandler 1966 Early Nantucket and Its Whale Houses. Hastings House, New York, NY. Freeman, Reverend James 1815 Notes on Nantucket, August 1st, 1807. Collections of the Massachusetts Historical Society, 2nd Series, V. 3, p. 19–38. Gardner, William E., and Jay Gibbs 1947 [1850] Nantucket Farms. In Proceedings of the Nantucket Historical Association, Fifty- Third Annual Meeting, pp. 43–46. Nantucket, MA. Gibson, Susan G. (editor) 1980 Burr’s Hill: A Seventeenth Century Wampanoag Burial Ground in Warren, Rhode Island. Haffenreffer Museum of Anthropology, Brown University, Providence, RI. Goodwin, John A. 1879 The Pilgrim Republic. Houghton Mifflin Company, New York, NY. Gookin, Daniel 1806 Historical Collections of the Indians in New England (1674). Massachusetts Historical Society Collections V.1:141–225. Monroe and Francis, Boston, MA. Hasenstab, Robert 1991 Wetlands as a Critical Variable in Predictive Modeling of Prehistoric Site Locations: A Case Study from the Passaic Basin. Man in the Northeast 42:39–61. Herbster, Holly, and Suzanne G. Cherau 2002 Archaeological Reconnaissance Survey, Town of Aquinnah, Martha’s Vineyard Massachusetts. PAL Report No. 1335. Submitted to the Massachusetts Historical Commission, Boston, MA, and Martha’s Vineyard Commission, Martha’s Vineyard, MA. Herbster, Holly, and Deborah C. Cox 2002 Archaeological Reconnaissance Survey, Town of Dartmouth, Dartmouth, Massachusetts. PAL Report No. 1328. Submitted to Dartmouth Historical Commission, Dartmouth, MA, and Massachusetts Historical Commission, Boston, MA. Herbster, Holly, and Kristen Heitert 2004 Archaeological Reconnaissance Survey, Town of Westport, Westport, Massachusetts. PAL Report No. 1494. Submitted to Westport Historical Society, Westport, MA. References 50 PAL Report No. 2585 Hohman, Elmo Paul 1928 The American Whaleman, A Study of Life and Labor in the Whaling Industry. Longmans, Green and Co., New York, NY. Holland, Sammuel 1765 Chart of the Coasts and Harbors of New England, ca. 1764-1765. Hume, Ivor Noel 1969 A Guide to Artifacts of Colonial America. Alfred A. Knopf, New York, NY. Ingham, Donna, and Mary Lynne Rainey 2005a Intensive (Locational) Archaeological Survey, Nantucket Post Office, Nantucket, Massachusetts. PAL Report No. 1748. Submitted to United States Postal Service, Windsor, CT. 2005b Intensive (Locational) Archaeological Survey, Wannacomet Water Company Improvements, Nantucket, Massachusetts. PAL Report No. 1759. Submitted to Wannacomet Water Company, Nantucket, MA. Johnson, Eric S. 1999 Community and Confederation: A Political Geography of Contact Period Southern New England, pp. 155–168. In The Archaeological Northeast. Edited by Mary Ann Levine, Kenneth Sassaman, and Michael S. Nassaney. Bergin & Garvey, Westport, CT. Jones, Olive, and Catherine Sullivan 1985 Glass Glossary. Parks Canada, Minister of the Environment, Ottawa, Ontario, Canada. Karr, Ronald Dale 1995 The Rail Lines of Southern New England, A Handbook of Railroad History. Branch Line Press, Pepperell, MA. Kerber, Jordan E. 2006 Cross-Cultural Collaboration. University of Nebraska Press, Lincoln, NE. King, Marsha 1988 Historic Site Location in Large Project Areas. Paper presented at the 28th Annual Meeting of the Northeastern Anthropological Association, Albany, NY. Kintigh, Keith 1992 Tools for Quantitative Archaeology, Programs for Quantitative Analysis in Archaeology. Tempe, AZ. Lang, Christopher J., and Kate Stout 1995 Building with Nantucket in Mind: Guidelines for Protecting the Historic Architecture and Landscape of Nantucket Island. Nantucket Historic District Commission, Nantucket, MA. Langlois, K.H., Jr. 1979 Soil Survey of Nantucket County, Massachusetts. United States Department of Agriculture Soil Conservation Service. U.S. Government Printing Office, Washington, D.C. References PAL Report No. 2585 51 Leveillee, Alan 1999 Transitional Archaic Ideology as Reflected in Secondary Burials at the Millbury III Cremation Complex. Archaeology of Eastern North America 27:157–183. Little, Elizabeth A. 1981 Historic Indian Houses of Nantucket. Nantucket Algonquian Studies No. 4. Nantucket Historical Association, Nantucket, MA. 1983 Initial Predictive Map for Prehistoric Sites on Nantucket. Nantucket Archaeology Studies No. 1. Archaeology Department, Nantucket Historic Association, Nantucket, MA. 1984 Locus Q–6, Site M52/65, Quidnet, Nantucket, Massachusetts. Bulletin of the Massachusetts Archaeological Society 45(1). 1988a History of the Town of Miacomet. Nantucket Algonquin Studies No. 12. Nantucket Historical Association, Nantucket, MA. 1988b The Indian Sickness at Nantucket 1763-1764. Nantucket Algonquian Study No. 11. Nantucket Historical Association, Nantucket, MA. 1996 Daniel Spotso: A Sachem at Nantucket Island, Massachusetts, circa 1691 - 1741. In Northeastern Indian Lives, 1632-1816. Edited by Robert S. Grumet. University of Massachusetts Press, Amherst, MA. Little, Elizabeth A., and J.C. Andrews 1982 Drift Whales at Nantucket: The Kindness of Moshup. Man in the Northeast 23:17–38. Little, Barbara, Erika Martin Seibert, Jan Townsend, John H. Sprinkle Jr., and John Knoerl 2000 Guidelines for Evaluating and Registering Archeological Properties. National Register Bulletin No. 36. U.S. Department of the Interior, National Park Service, National Register, History and Education, Washington, D.C. Luedtke, Barbara E. 1980 Survey of the University of Massachusetts, Nantucket Field Station. In Widening Horizons: Studies Presented to Dr. Maurice Robbins, edited by Curtiss Hoffman, pp. 95– 129. Massachusetts Archaeological Society, Attleboro, MA. MacGuire, Randall H., and Robert Paynter 1991 The Archaeology of Inequality. Basil Blackwell, Oxford, England. Macy, Obed. 1972 [1880] The History of Nantucket. Reprint of second edition, originally published in 1835. Augustus M. Kelley Publishers, Clifton, NJ. Marshall, Esther S. 1962 Polpis, Past and Present, Nantucket. The Nantucket Athaneum Collections, Nantucket, MA. References 52 PAL Report No. 2585 Massachusetts Highway Department (MHD) 2001 Aerial Photograph of the Cliff Road Multiuse Path Extension project area. On file at the Cultural Resources Unit (CRU) of the MassHighway Department, Boston, MA. Massachusetts Historical Commission (MHC) 1982a Historic and Archaeological Resources of Southeast Massachusetts. Massachusetts Historical Commission, Office of the Secretary of State, Boston, MA. 1982b Historic and Archaeological Resources of the Boston Area: A Framework for Preservation Decisions. Massachusetts Historical Commission, Office of the Secretary of State, Boston, MA. 1984a Historic and Archaeological Resources of the Connecticut Valley. Massachusetts Historical Commission, Office of the Secretary of State, Boston, MA. 1984b Town Reconnaissance Survey Report: Nantucket. Massachusetts Historical Commission, Office of the Secretary of State, Boston, MA. 1985 Public Planning and Environmental Review: Archaeology and Historic Preservation. Massachusetts Historical Commission, Office of the Secretary of State, Boston, MA. 1987 Historic and Archaeological Resources of Cape Cod and the Islands. Massachusetts Historical Commission, Office of the Secretary of State, Boston, MA. McManamon, Francis P. 1990 A Regional Perspective on Assessing the Significance of Historic Period Sites. Historical Archaeology 24(2):14–22. Miller, George L. 1990 Classification and Economic Scaling of Nineteenth Century Ceramics. Historical Archaeology 14(1):1–40. 1991 A Revised Set of CC-Index Values for English Ceramics. Historical Archaeology 25(1):1–25. Miller, George L., and Silas D. Hurry 1983 Ceramic Supply in an Economically Isolated Frontier Community: Portage County of the Western Ohio Reserve, 1800–1825. Historical Archaeology 17(2):80–92. Mitchell, William 1838 Map of the Island of Nantucket. E.W. Bouves, Boston, MA. Prrqh| References PAL Report No. 2585 53 Mulholland, Mitchell T. 1984 Patterns of Change in Prehistoric Southern New England: A Regional Approach. Unpublished Ph.D. dissertation, Department of Anthropology, University of Massachusetts, Amherst, MA. National Park Service (NPS) 1983 Archaeology and Historic Preservation: Secretary of the Interior's Standards and Guidelines. Federal Register 48(190). National Park Service, Department of the Interior, Washington, D.C. Newell, Aimee E. 2001 “No Harvest of Oil”: Nantucket’s Agricultural Fairs 1856-1890. Dublin Seminar for New England Folk Life, Proceedings. Fall 2001. Nicholas, George P. 1991 Places and Spaces: Changing Patterns in Wetland Use in Southern New England. Man in the Northeast 42:75–98. Oldale, Robert N. 1986 Late-Glacial and Postglacial Sea-Level History of New England: A Review of Available Sea Level Curves. Archaeology of Eastern North America 14:89–99. 1992 Cape Cod and the Islands: The Geologic Story. Parnassus Imprints, Orleans, MA. PAL 2004 Management Memorandum, Archaeological Site Examination of the Dwelling Site, Nantucket High School Staff Housing Project, Nantucket, MA. On file at the Massachusetts Historical Commission, Boston, MA. 2007 Technical Memorandum, Intensive (Locational) Archaeological Survey, Nantucket Human Services Center Buffer Zone, Nantucket, Massachusetts. PAL Report No. 1666.02. Submitted to Town of Nantucket, Center for Human Services, Nantucket, MA. Parker, Patricia, and Thomas F. King 1998 Guidelines for Evaluating and Documenting Traditional Cultural Properties. National Register Bulletin No. 38. U.S. Department of the Interior, National Park Service, National Register, History and Education, Washington, D.C. Prescott, J. 1831 Map of the Town of Nantucket, County of Nantucket, State of Massachusetts. Pretola, John, and Elizabeth A. Little 1988 Nantucket: An Archaeological Record from the Far Island. Bulletin of the Archaeological Society of Connecticut 51:47–68. Rainey, Mary Lynne 1998 Archaeological Reconnaissance Survey, Proposed Siasconset Wastewater Treatment Facility Locations: Airport Site (#30), Former Navy Base (#25), and Coast Guard Site (#18A), Nantucket, Massachusetts. PAL Report No. 987. Submitted to Earth Tech, Lexington, MA. References 54 PAL Report No. 2585 2000 Intensive (Locational) Archaeological Survey of the South Shore Links Golf Course Project Area, Nantucket, MA. PAL Report No. 1133.01. Submitted to Mr. Peter Dooley, Nantucket, MA. 2001 Intensive (Locational) Archaeological Survey, Proposed Old South Road and Fairgrounds Road Bicycle Paths, Nantucket, Massachusetts. PAL Report No. 1208. Submitted to Town of Nantucket Selectman’s Office, Nantucket, MA. 2004 Polpis Road Bicylce Path Archaeological Data Recovery Program: Site 19-NT-50, The Roadkill Site (19-NT-166), Site 19-NT-68, and the Folger’s Marsh Site (19-NT-180) and Supplemental Site Examination of the Folger’s Marsh Site, Nantucket, Massachusetts. Volumes I and II. PAL Report No. 621. Submitted to Nantucket County Planning and Economic Development Commission, Nantucket, MA. Rainey, Mary Lynne, and Donna Ingham 2005 Intensive (Locational) Archaeological Survey, Proposed Nantucket Human Services Center and Archaeological Site Examinations, Poison Meadow, Valley View, and Wild Rose Pasture Archaeological Sites, Nantucket, Massachusetts. PAL Report No. 1666.01. Submitted to Nantucket Council for Human Services, Nantucket, MA. Rainey, Mary Lynne, and Duncan Ritchie 1996 Site Examination on Fenceline, Interval, Vista, and Shadow Prehistoric Sites; and Coffin Farm Complex 1 and 2, Coffin Farmhouse 1, and Milestone Road Historic Sites Nantucket Golf Club Project Area, Nantucket, Massachusetts. The Public Archaeology Laboratory, Inc. Report No. 718. Submitted to The Nantucket Golf Club Inc., Edwards, CO. 1997 Intensive Survey, Miacomet Golf Course, Nantucket, MA. The Public Archaeology Laboratory, Inc. Report No. 763. Submitted to the Nantucket Land Bank Commission, Nantucket, MA and Hurdzan Golf Course Design, Columbus, OH. 1998 Intensive Archaeological Survey, School Perimeter Road Project Area, Nantucket, MA. The Public Archaeology Laboratory, Inc. Report No. 894. Submitted to the Nantucket Planning and Economic Development Commission, Nantucket, MA. 2001 Intensive (Locational) Archaeological Survey, Miacomet Golf Course Nine Hole Expansion, Nantucket, Massachusetts. PAL Report No. 1252. Submitted to Avalon Consulting Group, Taunton, MA. Rhode Island Historical Preservation Commission (RIHPC) 1982 Standards for Archaeological Survey. Rhode Island Historical Preservation Commission, Providence, RI. Ritchie, Duncan 1988 An Intensive Archaeological Survey of the Nantucket Public School Property, Nantucket, Massachusetts. The Public Archaeology Laboratory, Inc. Report No. 124. Submitted to Pierce and Kramer, Inc., Boston, MA. References PAL Report No. 2585 55 1989 An Intensive Archaeological Survey of the Proposed Madaket Road Bicycle Path, Nantucket, Massachusetts with a contribution by Elizabeth A. Little, Nantucket Historical Association. The Public Archaeology Laboratory, Inc. Report No. 136. Submitted to Vanasse Hangen Brustlin, Inc., Boston, MA. 2010 Intensive (Locational) Archaeological Survey, Nantucket Disc Golf Project, Nantucket, Massachusetts. PAL Report No. 2507. Submitted to Nantucket Disc Golf, Nantucket, MA. Ritchie, Duncan, Marsha K. King, and Martha Lance 1988 Archaeological Survey of Westville Dam and Reservoir in Southbridge and Sturbridge, Massachusetts. The Public Archaeology Laboratory, Inc. Report No. 158-2. Submitted to IEP, Inc., Northborough, MA and the Army Corps of Engineers, New England Division, Waltham, MA. Robinson, Paul, Marc Kelley, and Patricia E. Rubertone 1985 Preliminary Biocultural Interpretations from a Seventeenth-Century Narragansett Indian Cemetery in Rhode Island. In Cultures in Contact: The European Impact on Native Cultural Institutions in Eastern North America, A.D. 1000-1800. Smithsonian Institution, Washington, D.C. Rosier, James 1843 [1605] A True Relation of the Most Prosperous Voyage by Captain George Waymouth. Massachusetts Historical Society Collections 3 (8):125–157. Roy, Edward 1956 A Steatite Vessel from Nantucket. Bulletin of the Massachusetts Archaeological Society 17(3):51. Scott, Elizabeth M. 1994 Those of Little Note: Gender, Race, and Class in Historical Archaeology. University of Arizona Press, Tucson, AZ. Simmons, William S. 1970 Cautantowwit’s House: An Indian Burial Ground on the Island of Conanicut in Narragansett Bay. Brown University Press, Providence, RI. Simon, Brona G. 1988 Preliminary Field Report: Miacomet Village Elderly and Family Housing/Miacomet Praying Indian Burial Ground, Nantucket. Report on file at the Massachusetts Historical Commission, Boston, MA. 1991 Prehistoric Land Use and Changing Paleoecological Conditions at Titicut Swamp in Southeastern Massachusetts. Man in the Northeast 42:63–74. Snow, Dean 1980 The Archaeology of New England. Academic Press, New York, NY. South, Stanley A. 1977 Method and Theory in Historical Archaeology. Academic Press, New York, NY. References 56 PAL Report No. 2585 Starbuck, Alexander 1924 The History of Nantucket County, Island and Town. C.E. Goodspeed and Co., Boston, MA. 1989 History of the American Whale Fishery. Castle Books, Secaucus, NJ. Thorbahn, Peter F. 1982 The Prehistoric Settlement Systems of Southern New England: Final Report of The Interstate 495 Archaeological Data Recovery Program, vol. I. Public Archaeology Laboratory, Department of Anthropology, Brown University Report. Submitted to the Massachusetts Department of Public Works, Boston, MA. Thorbahn, Peter, F., Leonard Loparto, Deborah Cox, and Brona Simon 1980 Prehistoric Settlement Processes in Southern New England: A Unified Approach to Cultural Resource Management and Archaeological Research. Public Archaeology Laboratory, Department of Anthropology, Brown University Report. Report on file, Massachusetts Historical Commission, Office of the Secretary of State, Boston, MA. Trinkaus, Erik 1982 The Human Skeleton From the Nantucket Field Station Site. Bulletin of the Massachusetts Archaeological Society 43(2):37–39. Turchon, Frederic 1979 Report on the Archaeological Investigations Conducted on the University of Massachusetts Nantucket Field Station for the Proposed Field Station Sewage Disposal System. Report submitted to the Commonwealth of Massachusetts, University of Massachusetts, Boston, MA. United States Geological Survey (USGS) 1901 Nantucket quadrangle map (based on 1887 survey data). On file at the Nantucket Historical Association, Edouard A. Stackpole Library and Research Center, Nantucket, MA. Walling, H.F. 1856 Map of Nantucket. On file at PAL, Pawtucket, RI. Willan, Steven, and Duncan Ritchie 1995 Reconnaissance and Intensive Archaeological Surveys, Nantucket Memorial Airport Perimeter Fence, Nantucket, Massachusetts. The Public Archaeology Laboratory, Inc. Report No. 595. Submitted to Baystate Environmental Consultants, Inc., East Longmeadow, MA. Worth, Henry Barnard 1992 [1901] Nantucket Lands and Land Owners. Reprinted by the Nantucket Historical Association, Heritage Books, Inc., Bowie, MD. Nantucket, MA (project #225139)Woodard & Curran CWMP Update September 2014 APPENDIX H: SURFSIDE WWTF DATA CAPACITY ANALYSIS TECHNICAL MEMORANDUM AECOM MEMO MUIR ENERGY MEMO GROUNDWATER DISCHARGE PERMIT BRP – 11 (CD) BRP – 83 (CD) O&M MANUAL (CD) 980 Washington Street | Suite 325 Dedham, Massachusetts 02026 www.woodardcurran.com T 800.446.5518 T 781.251.0200 F 781.251.0847 MEMORANDUM TO:Kara Buzanoski, DPW Director and David Gray, Chief Operator FROM:Jon Himlan DATE:July 2, 2014 RE:Surfside Wastewater Treatment Facility Capacity Assessment This memo provides a summary of Woodard & Curran’s assessment of the capacity for the Surfside Wastewater Treatment Facility (WWTF) to receive and treat the future wastewater flow from the existing sewer areas and the needs areas, identified through in the Comprehensive Wastewater Management Plan (CWMP) Update, at the future build-out condition. This assessment is important for the Town’s sewer planning with the primary focus being whether or not projected wastewater flow from Madaket and Warren’s Landing can be sent to the Surfside WWTF. If the Surfside WWTF has capacity for these areas, it eliminates the need to construct a new WWTF for Madaket and Warren’s Landing which has been estimated by others to cost $45 million dollars. For this assessment, we estimated the Surfside WWTF existing and projected influent flow and pollutant loads; reviewed the current operation and performance; and calculated the hydraulic capacity and the treatment capacity. Our findings were as follows: The future condition, identified in the CWMP Update, is a maximum daily flow of 4.0 million gallons per day (MGD) which includes build-out of the existing sewer areas and sewer extension to the needs areas. The Surfside WWTF has sufficient capacity to receive wastewater at the future condition provided that minor changes are made to operational practices and two additional blowers are installed. Although the Surfside WWTF has capacity, the future maximum daily flow of 4.0 MGD exceeds the MassDEP groundwater discharge permit limit of 3.5 MGD for daily flow to the groundwater discharge beds. Therefore, expansion of the groundwater discharge capacity or revisions to the groundwater discharge permit are required. Note that revisions to the groundwater discharge permit would be required at the future condition even if Madaket and Warren’s Landing wastewater was not treated at the Surfside WWTF. Woodard & Curran and the Town have submitted the required documentation to MassDEP for this increased capacity and based on our discussions with MassDEP we understand that a revised discharge permit with the required flow increase will be issued soon. The following table summarizes the capacity of each unit process on a maximum daily flow equivalent basis. It is noted that each unit process was not necessarily evaluated on a maximum daily flow basis, but for comparison with the WWTF discharge permit (maximum daily limit), the applicable flow parameter used in our analysis (average daily, maximum monthly, or peak hourly) was converted to the equivalent maximum daily flow. The table also describes what the limiting parameter is (either hydraulic or treatment capacity). Table 1: Summary of Unit Process Capacity Unit Process Capacity at Maximum Daily Flow Equivalent (MGD) Limiting Parameter (Hydraulic or Treatment Capacity) Aerated Grit Chamber 4.0 Treatment capacity limited to 7.7 MGD on a peak hourly flow basis Primary Clarifiers 4.6 Hydraulic capacity limited to 8.8 MGD on a peak hourly flow basis Advanced Treatment System 4.0 Treatment capacity (membrane filters) limited to 7.7 MGD on a peak hourly flow 2014-07-02 Capacity Assessement Memo 2 July 2014 Unit Process Capacity at Maximum Daily Flow Equivalent (MGD) Limiting Parameter (Hydraulic or Treatment Capacity) basis Ultraviolet Disinfection 4.0 Treatment capacity limited to 7.7 MGD on a peak hourly flow basis Effluent Disposal Beds (Based on Permit not Hydraulic Analysis) 3.5 Hydraulic capacity limited to 3.5 MGD on a maximum daily flow basis (results from permitted limit which could potentially be increased) The following further describes the existing and projected influent flow and pollutant loads and the capacity analysis. 1.Influent Flow and Pollutant Loads We developed the influent flow and pollutant loads for the future condition from the existing average daily summer (June to August) flow and loads data by adding the projected increase in average daily flow and loads resulting from build-out and sewer system expansion to the needs areas. The parameters of maximum monthly, maximum daily, and peak hourly at the future condition were determined by applying the respective ratio to average daily summer flow and loads from existing data to the projected increase (i.e. existing average daily plus projected average daily multiplied by the ratio from existing data). Table 2 describes the existing and projected influent flows and pollutant loads. 1.1.Existing Flow Existing flow is based on the data collected by the Surfside WWTF Supervisory Control and Data Acquisition (SCADA) system and the data contained in the Discharge Monitoring Reports (DMRs) that the Town submits to the Massachusetts Department of Environmental Protection (MassDEP). The data evaluated was for the period between February 2009 and March 2013. Woodard & Curran analyzed the existing flow data for the following parameters: Average Daily Summer: The average daily conditions for the months of June, July and August based on the DMR data. The average daily summer flow is important as a “benchmark” condition because the Surfside WWTF experiences a seasonal variation in flow as a result of the transient / tourist nature of the population with the highest occupancy occurring during the summer months. Maximum Monthly: Represents conditions that are expected to be exceeded once for each 12 occurrences, or one month per year. The maximum monthly flow is important as the parameter used for assessment of the biological treatment capacity of the advanced treatment system (membrane bioreactor) and the capacity of the solids processing systems. The maximum monthly flow is determined by developing the frequency distribution for the DMR data and selecting the value closest to the 91.7 percent exceedance value (i.e., exceeded 8.3 percent of the time, or one in twelve). Figure 1 illustrates the maximum monthly flow in relation to the average monthly flow and the 30-day moving average flow. From this data we calculated that the ratio of maximum monthly flow to average daily summer flow is approximately 1.1. Nantucket, MA Projected and Existing Flows and Loads at the Surfside WWTF 7/2/2014 Table 2 - Projected and Existing Influent Flows and Pollutant Loads Flow (MGD)BOD5 Load (lbs/day)TSS Load (lbs/day) Total Nitrogen Load (lbs/day) Average Daily - Summer Maximum Monthly Maximum Daily Peak Hourly Average Daily Maximum Monthly Average Daily Maximum Monthly Average Daily Maximum Monthly Projected by Study / Need Area Madaket 0.16 490 560 90 Warren's Landing 0.03 100 110 20 Hummock Pond South 0.07 200 230 40 Hummock Pond North 0.09 290 330 50 Somerset 0.10 320 360 60 Monomoy 0.08 260 300 50 Shimmo 0.06 190 220 30 Town 0.59 1,800 2,050 330 Nantucket PLUS 0.07 230 260 40 Miacomet 0.07 210 240 40 Subtotal Projected 1.33 1.42 1.82 3.52 4,090 4,660 750 Projected Infiltration/Inflow (Future) 0.06 0.06 0.06 0.06 Total Projected 1.39 1.48 1.88 3.58 4,090 4,790 4,660 6,150 750 860 Existing Conditions at Surfside WWTF 1.53 1.64 2.10 4.06 4,990 5,830 3,490 4,610 530 610 Total Projected and Existing (Future Conditions)2.9 3.1 4.0 7.7 9,100 10,600 8,200 10,800 1,300 1,500 \\Dedham\projects\225139 Nantucket MA - CWMP Update\wip\Flows and Loads\2013.11.06 FlowsandLoads FINAL - JEH Summary 0.75 1.00 1.25 1.50 1.75 Flow (MGD) Date Figure 1 Nantucket Surfside WWTF Existing Influent Flow - Monthly 30-Day Moving Average Average Monthly Flow Maximum Month 2014-07-02 Capacity Assessement Memo 5 July 2014 Maximum Daily: Represents conditions that are expected to be exceeded once for each 365 occurrences, or once per year. The maximum daily flow is important because the Surfside WWTF Groundwater Discharge Permit specifies the maximum daily flow that can be discharged. The maximum daily flow is determined by developing the frequency distribution for the DMR data and selecting the value closest to the 99.7 percent exceedance value (i.e., exceeded 0.3 percent of the time – one in three hundred sixty five). Figure 2 illustrates the maximum daily flow in relation to the daily flow values and the average monthly flow. From this data we calculated that the ratio of maximum daily flow to average day summer flow is approximately 1.4. Peak Hourly: The peak hourly condition represents the highest flow observed during any 60-minute period over the range of data. The peak hourly flow is important as the parameter used for assessment of the hydraulic capacity of the Surfside WWTF. The peak hourly flow was determined by calculating a running average of 60 one-minute intervals from the SCADA data. The highest 60-minute running average of the entire data range was considered the peak hourly flow. From this data we calculated that the ratio of peak hourly flow to average daily summer flow is approximately 2.6. 1.2.Existing Influent Pollutant Loads Woodard & Curran evaluated the existing influent pollutant load data for the average daily summer and maximum month parameters using the same methodology as described for the existing flows. The existing load data is based on the DMRs for the period from January 2010 to December 20111 for the following pollutants: Biochemical oxygen demand, 5-day (BOD5): influent data is collected once per week. Figure 3 illustrates the weekly data, the 30-day moving average and the maximum monthly BOD5 load. From this data we calculated that the ratio of maximum monthly BOD5 to average daily BOD5 is 1.2. This ratio is consistent with the typical ratio of 1.26 referenced in the New England Interstate Water Pollution Control Commission, 2011 Guides for the Design of Wastewater Treatment Works (TR-16). Total suspended solids (TSS): influent data is collected once per week. Figure 4 illustrates the weekly data, the 30-day moving average and the maximum monthly TSS load. From this data we calculated that the ratio of maximum monthly TSS to average daily TSS is 1.3. This ratio is consistent with the typical ratio of 1.3 referenced in TR-16. Total nitrogen (TN): influent TN data is not collected as it is not a permit requirement. However, influent ammonia-nitrogen data is collected once per week. To estimate influent TN, we assumed that the influent ammonia is 65-percent of the influent total Kjeldahl nitrogen (TKN) based on information from the Metcalf & Eddy, Wastewater Engineering Treatment and Reuse Textbook, fourth edition (page 670). We also assume that the influent TKN is equal to the influent TN, because the concentration of nitrate and nitrite in raw wastewater is typically negligible. From this data we calculated that the ratio of maximum monthly TN to average daily TN is 1.2 As shown in Figures 3 and 4, there is the strong seasonal variation in wastewater load resulting from the seasonal fluctuations in population. The flows and concentrations approximately double from a low point in mid-winter (February) to a high point in mid-summer (August). This results in a three- to four-fold increase in influent pollutant loads to the WWTF from winter to summer. 1 The pollutant data from 2012 was excluded from our analysis because the loadings in July and August were extremely high even though the flow rate was typical. Based on input from the WWTF staff, we believe this high loading condition was the result of high solids in the WWTF internal recycle streams and not representative of the influent wastewater. 0.50 1.00 1.50 2.00 2.50 3.00 Flow (MGD) Date Figure 2 Nantucket Surfside WWTF Existing Influent Flow - Daily Daily Flow Average Monthly Flow Maximum Daily Flow 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 Loads (lbs/day) Date Figure 3 Nantucket Surfside WWTF Existing Influent BOD Load Max Month Load (2010-2011)30-Day Moving Average BOD Load Excluded from Analysis 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 11,000 12,000 13,000 14,000 15,000 16,000 Loads (lbs/day) Date Figure 4 Nantucket Surfside WWTF Influent TSS Load Max Month (2010-2011)30-Day Moving Average TSS Load Excluded from Analysis 2014-07-02 Capacity Assessement Memo 9 July 2014 We compared the average daily summer existing influent pollutant data on a concentration basis (load divided by flow), in milligrams per liter (mg/l), with published data on typical domestic wastewater concentrations (Metcalf & Eddy, Wastewater Engineering, Fourth Edition, Table 3-15). We found that the Surfside WWTF influent wastewater, during summer conditions, would generally be considered high- strength as shown in the following Table 3. It is also noted that the BOD5 concentration is higher than the TSS concentration, which is somewhat unusual (BOD5 concentration is typically about 80 to 85 percent of the TSS concentration). This high BOD5 concentration could be caused by the decant of the sludge holding tanks which are not being consistently aerated which could result in fermentation and the production of volatile fatty acids (BOD5source). Table 3: Comparison of Existing Wastewater Pollutant Concentration with Published Values Pollutant Average Summer Existing Surfside WWTF Concentration Typical Medium Strength Concentration Typical High Strength Concentration BOD5,mg/l 390 190 350 TSS, mg/l 270 210 400 1.3.Projected Flow Woodard & Curran projected future flow based on a build-out analysis of the defined needs areas. The selection of needs areas and the build-out projections were performed as part of our ongoing comprehensive review and update to the Town’s 2004 Comprehensive Wastewater Management Plan (CWMP). The needs areas and our build-out analysis included input and data from the Nantucket Planning & Economic Development Department.The primary changes from the 2004 CWMP for our projections are as follows: Included the Hummock Pond South and Hummock Pond North study areas. Utilized new zoning adopted by the Town. Performed a detailed account of the potential build-out from secondary dwelling units. The previously presented Table 2 provides the projected wastewater flow which was determined based on the following: The of number of future residential units and commercial land acres that could be connected to the sewer collection system (existing or through sewer extensions) for each needs area were projected from the build-out analysis. The number of residential units and commercial acres were multiplied by the unit flow rates (taken from the 2004 CWMP) of 320 gallons per day per unit (gpd/unit) and 345 gpd/acre, respectively, to estimate the projected flow from each needs area on an average daily basis. The ratios (determined from existing data) of average daily flow to maximum monthly flow, maximum daily flow, and peak hourly flow were applied to calculate the respective flow parameter. The wastewater flow presented in Table 2 consists of the sanitary wastewater component generated from the residential and commercial sources, septage received from haulers, and the extraneous inflow and infiltration (I/I) flow component contributed from groundwater and precipitation. We have accounted for the future I/I and septage as follows: 2014-07-02 Capacity Assessement Memo 10 July 2014 Inflow and Infiltration: The flow at the future condition includes an increase in I/I resulting from the installation of new sewer pipe and manholes. Although the Town is undergoing work to remove I/I, for this analysis, we have conservatively assumed that the existing I/I amount will remain constant. Septage: We have made the assumption that the septage volume received in the future will remain constant. This assumption is conservative because as sewer expansion occurs, there will be fewer active septic systems and the volume of septage will likely decrease. 1.4.Projected Pollutant Loads The projected pollutant loads were determined based on the build-out analysis described above. The previously presented Table 2 provides the projected pollutant loads in pounds per day (lbs/day) which were calculated based on the following: The of number of future residential units and commercial land acres that could be connected to the sewer collection system (existing or through sewer extensions) for each needs area were projected from the build-out analysis. The number of residential units and commercial acres were multiplied by the following unit load rates (taken from the 2004 CWMP) to estimate the projected pollutant load from each needs area on an average daily basis: o BOD5: 0.99 lbs/day-unit (0.22 lbs/day-person x 4.5 persons per unit) for residential; and 0.72 lbs/day-acre (250 mg/l x 345 gpd/acre) for commercial. o TSS: 1.13 lbs/day-unit (0.25 lbs/day-person x 4.5 persons per unit) for residential; and 0.86 lbs/day-acre (300 mg/l x 345 gpd/acre) for commercial. o TN: 0.18 lbs/day-unit (0.04 lbs/day-person x 4.5 persons per unit) for residential; and 0.12 lbs/day-acre (40 mg/l x 345 gpd/acre) for commercial. The ratio (determined from existing data) of average daily load to maximum monthly load was applied to calculate the load for each pollutant (BOD5, TSS, and TN). 2.Capacity Assessment Our capacity assessment included calculation of the hydraulic capacity and treatment capacity for each of the Surfside WWTF unit processes. As previously described, each unit process was not necessarily evaluated on a maximum daily flow basis, but for comparison with WWTF discharge permit limit, the applicable flow parameter for our analysis (average daily, maximum monthly, or peak hourly) was converted to the equivalent maximum daily flow. Section 2.1 describes the hydraulic capacity for the WWTF followed by Sections 2.2 through 2.6 which describe our assessment of the treatment capacity for each individual unit process, including the current operation and performance, calculated capacity, and our recommendations. 2.1.Hydraulics Computations were made of the connecting piping and the unit processes through the WWTF at incremental peak hourly flows of one MGD. A summary of peak hourly flow limitations and the maximum daily flow equivalent for all the unit processes is presented in Table 4. The WWTF was found to have sufficient hydraulic capacity to handle the projected maximum daily flow of 4.0 MGD (peak hourly flow of 7.7 MGD). 2014-07-02 Capacity Assessement Memo 11 July 2014 Table 4: Unit Process Hydraulic Capacity Unit Process Hydraulic Peak Hourly Flow Capacity (MGD) Maximum Daily Flow Equivalent (MGD) Influent Parshall Flume 10.4 5.4 Grit Chamber 13.6 7.0 Primary Clarifiers 8.8 4.6 Advance Treatment – Anoxic/Aeration Tanks1 24.0 4.8 Advanced Treatment - Membranes 7.7 4.0 Ultraviolet Disinfection 7.7 4.0 Effluent Parshall Flume 21.4 11.1 Effluent Piping to Disposal Beds 8.0 4.1 2.2.Headworks 2.2.1.Current Operation and Performance The upgrades completed in 2009 included installation of a grinder that has been rendered inoperable due to hydrogen sulfide corrosion. In addition, concrete corrosion from hydrogen sulfide is visible at the grit chamber effluent weir. Woodard & Curran performed an evaluation recommending the installation of a fine screen to replace the grinder. In addition, we performed an assessment for corrosion control which recommends installation of a pure oxygen injection system at the Sea Street Pump Station to mitigate hydrogen sulfide corrosion. According the 2010 Facility O&M Manual, Appendix A, the aerated grit chamber has dimensions of 17 feet by 15 feet, with a side water depth of 14.83 feet. The 2010 Facility O&M Manual, Appendix A, also indicates there are two blowers each with a capacity of 120 cubic feet per minute. The existing aerated grit chamber appears to be performing sufficiently under current operating conditions. Operations staff report concerns with the location of the grit screw mechanism as it is in the direct path of influent flow and is therefore vulnerable to wear from the grit in the influent wastewater. 2.2.2.Capacity The grit chamber has sufficient volume and aeration for a peak hourly flow of 7.7 MGD (4.0 MGD maximum daily flow equivalent). Table 5 summarizes the Surfside WWTF grit chamber in comparison to TR-16 recommended values. As indicated, the grit chamber length-to-width ratio is not consistent with TR-16 standards. 1 Anoxic/Aeration tanks were designed to receive return activated sludge flow at 4 times the influent forward flow. 2014-07-02 Capacity Assessement Memo 12 July 2014 Table 5: Comparison of Grit System Design Data with Recommended Values Parameter TR-16 Recommended Value (1) Surfside WWTF (2) Length-to-Width Ratio 3:1 to 8:1 0.9:1 Residence Time (minutes) at Peak Hour Flow of 7.7 MGD 3 to 10 7.8 Air Flow Rate (scfm) per foot of length (3)3 to 8 8 Notes: (1) Recommended values from TR-16 (2011) (2) Data for Surfside WWTF calculated from values presented in the O&M manual (3) Assumes 1 of 2 blowers on line. Although the TR-16 recommended residence time and air flow rate suggest higher flows could be acceptable, we do not recommend increasing peak flows to the existing grit system above 7.7 MGD as it may result in bypassing of more and larger grit to the primary clarifiers. 2.2.3.Recommendations Woodard & Curran performed an evaluation recommending the installation of screening and a new vortex grit system to replace the grinder and corroded grit chamber structure. These findings and recommendations are provided in a memo titled, “Influent Screening Alternatives Assessment.” In addition, we engaged a subconsultant (Bowker &Associates, Inc.), who performed an assessment of corrosion control which recommends installation of a pure oxygen injection system at the Sea Street Pump Station to mitigate corrosion. These findings and recommendations are provided in a report prepared by Bowker &Associates, Inc. titled, “Control of Hydrogen Sulfide Corrosion at the Surfside WWTF.” 2.3.Primary Clarifiers 2.3.1.Current Operation and Performance The current practice is to utilize all three primary clarifiers under normal conditions. According the 2010 Facility O&M Manual, each primary clarifier has a surface area of 1,467 square feet (81.5 feet by 18 feet). At the current average daily flow condition, the clarifiers have low overflow rates and high residence times. As a result, the BOD5 removal has been greater than 50 percent under both average and maximum month conditions. This exceeds both the typical values found in industry literature and the design performance of 30 percent BOD5 removal listed in the 2010 Facility O&M Manual. Data was not available to estimate TSS removal but it assumed to be a high removal rate given the BOD5 removal performance. 2.3.2.Capacity The primary clarifiers have sufficient capacity to handle the projected flow and pollutant loads. Table 6 summarizes the highest flow that can be received and not exceed the TR-16 recommendations for maximum surface overflow rate (SOR), in gallons per day per square foot (gpd/sf), at average daily flow and the SOR at peak hourly flow with one clarifier out of service. At the projected maximum monthly flow rate, we estimate the BOD5 and TSS removal to be 33 percent and 55 percent respectively. 2014-07-02 Capacity Assessement Memo 13 July 2014 Table 6: Primary Clarifier Analysis Flow, MGD Maximum Daily Flow Equivalent, MGD Average Daily SOR; maximum of 1,200 gpd/sf 5.3 7.2 Peak Hourly SOR with one Clarifier Out of Service; maximum of 3,000 gpd/sf 8.8 4.6 2.3.3.Recommendations There are no improvements required for capacity reasons. 2.4.Advanced Treatment 2.4.1.Current Operation and Performance Current operation of the advanced treatment system (ATS) has resulted in effluent that is compliant with the MassDEP Groundwater Discharge Permit, however, during our operational assessment on April 15 through April 17, 2013 we identified several items that were a concern for future capacity. These items are summarized in the following: Insufficient Oxygen and Filamentous Organisms: We found a significant amount of filaments in the mixed liquor suspended solids (MLSS) biomass which is the result of insufficient oxygen and anaerobic conditions. The abundance of filaments is a concern because it indicates that the environment is potentially inhibiting or stressful to the bacteria that the ATS system relies on for biological removal of BOD5, TSS and nitrogen. To evaluate this condition, we took a sample of the MLSS and performed a microbiological assessment which showed an abundance of Thiothrix - a sulfide induced filament. This finding indicated that there was insufficient oxygen and anaerobic conditions at the WWTF. To address these conditions the Woodard & Curran worked with the Surfside WWTF staff to implement the following measures: : o The sludge storage tanks were not being aerated resulting in the sludge becoming anaerobic. The sludge tank decant and sludge dewatering pressate streams were conveyed to the WWTF influent which ultimately flows to the ATS and contributes to an unhealthy biomass. On/off aeration operation of the sludge holding tanks was implemented to prevent anaerobic conditions from developing there. o Septage and leachate received at the WWTF were conveyed to the WWTF influent. Septage and leachate are anaerobic and high in sulfide, organic acids, and other constituents that contribute to an unhealthy biomass. The current operation is to send septage and leachate directly to the sludge holding tanks as opposed to the WWTF influent which corrected this concern. o The aeration tanks were being operated with an on/off aeration strategy which was not consistent with the design of the ATS. It is our understanding that the reason for this operating strategy was a concern from the former Chief Operator that return activated sludge (RAS) to the anoxic tanks was high in dissolved oxygen (DO) from the membrane scour air and that the high DO was inhibiting denitrification. 2014-07-02 Capacity Assessement Memo 14 July 2014 While we agreed that RAS with a high DO is a concern to some extent, DO profiles performed by operations staff on April 21, 2013 and July 2, 2013 found that the DO concentrations were significantly low in the aeration tanks (less than 1 mg/l) and acceptable, although not ideal, in the anoxic tanks (0.11 to 0.26 mg/l in the anoxic tanks with 3 to 9 mg/l in the membrane tanks). In addition, our review of the available effluent nitrate data did not indicate denitrification problems. We believe that the denitrification concerns (high effluent total nitrogen) could have been misinterpreted and could just as easily have been a lack of nitrification (conversion of ammonia to nitrate), because if there is not sufficient oxygen to convert ammonia to nitrate, then there is not enough nitrate in the anoxic tanks to denitrify. Operations staff have now increased aeration in the aeration tanks which should help to establish a healthy biomass and result in more robust nitrification. Because WWTF staff are concerned with denitrification they have extended the anoxic zone by turning off the air to the first zone of the aeration tanks.. This practice has been successful and has resulted in very low effluent total nitrogen. However, under the projected future load conditions, the first zone of the aeration tanks will likely be needed to provide adequate aeration. Therefore to further understand the staff’s denitrification concerns and plan for future conditions, we have recommended a program of nitrate sampling and analysis for various locations in the process train . Dissolved Oxygen Control: During the operational assessment site visit, operations staff reported that the dissolved oxygen control instrumentation is not reliable and cannot be utilized for aeration tank blower control as was the original design intent. While DO control is not a direct capacity concern, replacement of these instruments with more reliable DO and oxidation reduction potential (ORP) measurement capability would enhance the ability to operate the WWTF at the future condition. 2.4.2.Capacity The ATS treatment capacity is a function of two processes: (1) biological (activated sludge) treatment in the anoxic and aeration tanks and (2) solids separation through membrane filtration. To assess the activated sludge treatment capacity, we performed calculations to predict the amount of biomass and oxygen required to remove the BOD5, TSS and nitrogen loads to meet the permit limits at the future condition. For oxygen requirements we used maximum daily load conditions (as recommended by TR-16 for blower capacity), for all other parameters, we used maximum monthly load conditions. To assess the membrane filtering capacity, we calculated the flow rate at the manufacturer’s recommended maximum flux rate for the square footage of membranes installed. Based on our calculations for oxygen requirements, we determined that the 3 existing aeration tank blowers do not have enough capacity for the future condition, therefore two additional blowers are needed (one to provide the additional capacity required and one to serve as a redundant backup). We also assessed the air diffusers and air distribution piping and determined that they have capacity to receive the higher air flow rates as follows: Diffusers: the air flow rate per diffuser would be 2.4 cubic feet per minute (cfm) at maximum monthly conditions and 4.7 cfm at maximum daily conditions. These values are within the manufacturer’s recommended maxim air flow rates of 4 cfm for long-term durations and 7 cfm for short-term durations. 2014-07-02 Capacity Assessement Memo 15 July 2014 Air Distribution Piping: at maximum monthly conditions, the velocity in the air distribution piping would be 3,800 feet per minute (fpm) in the 8-inch diameter air piping (1,330 cfm). The typical recommended maximum air flow rate in air distribution piping is 4,000 fpm. With this additional blower capacity, the ATS has sufficient capacity for the flow and loads at the future condition. Table 7 summarizes the key parameters of our assessment of the ATS capacity. Table 7: Advanced Treatment Capacity Assessment Parameter Value Notes/Basis Influent/Effluent Flow and Quality Flow, Maximum Month (MGD)3.1 Flow, Maximum Daily (MGD) 4.0 For comparison with permitted flow. The capacity assesment is based on maximum monthly flow and load conditions. Raw Influent BOD (mg/l)408 Flow and load projections at maximum month Raw Influent TSS (mg/l)414 Flow and load projections at maximum month Raw Influent TKN (mg/l)56 Flow and load projections at maximum month ATS Influent BOD (mg/l)273 Primary clarifier removal percentage previously described at maximum month ATS Influent TSS (mg/l)187 Primary clarifier removal percentage previously described at maximum month ATS Influent TKN (mg/l)56 Flow and load projections at maximum month ATS Effluent BOD (mg/l)5 GE Zenon, 2006 Design Calculations ATS Effluent TSS (mg/l)5 GE Zenon, 2006 Design Calculations ATS Effluent TN (mg/l)10 Discharge Permit Limit Temperature (degrees C)21 Summer, when maximum flows and loads occur Anoxic Preanoxic Tank Volume (gallons)192,393 AECOM 2012 Record Drawings Mixed Liquor Volatile Suspended Solids (MLVSS) Concentration in the Preanoxic Tank (mg/l)5,700 Calculated Specific Denitrification Rate (g Nitrate Removed / g MLVSS)0.2 Metcalf & Eddy, Wastewater Engineering, 4th Edition, Figure 8-23 Aeration Aeration Tank Volume (gallons)560,781 AECOM 2012 Record Drawings and aeration in the post anoxic tanks Membrane Tank Volume (gallons) 220,554 AECOM 2012 Record Drawings and assume 10% of membrane tank occupied by equipment (same assumption as GE Zenon 2007 Design Calculations) Aeration Tank and Membrane Tank Total Hydraulic Retention Time (hours)6 Calculated Return Activated Sludge Rate (MGD)15.6 4 times influent flow per GE Zenon 2006 Design 2014-07-02 Capacity Assessement Memo 16 July 2014 Parameter Value Notes/Basis Calculation Mixed Liquor Suspended Solids Concentration (mg/l)8,000 GE Zenon, 2006 Design Calculations Target Solids Retention Time (days)13 AECOM O&M Manual, page 4-33 Sludge Yield (lbs TSS/lbs BOD)0.56 Calculated Total Oxygen Required, Maximum Month (lbs/day)13,500 Calculated Oxygen Required to Aeration Tanks, Maximum Month (lbs/day)9,700 Remainder of required oxygen provided by membrane scour air Total Oxygen Required, Maximum Day (lbs/day)22,000 Calculated Oxygen Required to Aeration Tanks, Maximum Day (lbs/day)16,000 Remainder of required oxygen provided by membrane scour air Aeration Tank Actual Oxygen Transfer Efficiency (%)10% Calculated Required Air Flow Rate, Aeration Tanks, Maximum Month (scfm)3,900 Calculated Required Air Flow Rate, Aeration Tanks, Maximum Day (scfm)6,400 Calculated Available Air Flow Rate, Aeration Tanks (scfm)2,900 Aerzen O&M Manual for 3 aeration tank blowers Membrane Filtration Total Membrane Area (sq. ft.)312,800 GE Zenon O&M Manual, page 3-7 - 4 trains x 230 modules/train x 340 sf/module Flux at Average Daily Flow (gal/day-sq. ft)4.2 Recommended maximum flux is 13.3 gal/day-sq. ft. per GE Zenon, 2006 Design Calculations Flux at Maximum Daily Flow (gal/day- sq. ft)6.5 Recommended maximum flux is 20.7 gal/day-sq. ft. per GE Zenon, 2006 Design Calculations Flux at Peak Hourly Flow (gal/day-sq. ft.)7.7 Recommended maximum flux is 24.5 gal/day-sq. ft. per GE Zenon, 2006 Design Calculations Note that the ATS design included tankage between the aeration tank and the membrane tank that can be operated in either an aerobic mode or an anoxic mode. In the facility O&M Manual, this tankage is referred to as the “future post-anoxic stage.” Although it is not clear what the future condition is that would require a post-anoxic stage, we interpret it to be in case the Town were to be issued a new ground water discharge permit with a more stringent total nitrogen limit. While we do not anticipate that the Surfside WWTF would be receiving a more stringent total nitrogen limit, we calculated the ATS capacity with and without aeration in the post anoxic tank and maintaining the same design solids retention time (SRT) of 13 days. Under either condition (with or without aeration in the post anoxic tank), the ATS has enough capacity for the future projected flows and loads at the existing total nitrogen limit. 2.4.3.Recommendations. Operational Recommendations: Incorporate the operational recommendations described in 2.4.1. 2014-07-02 Capacity Assessement Memo 17 July 2014 Aeration Capacity: As described in Table 7, the required air flow rate to the aeration tanks is less than the existing available air flow rate (3 aeration blowers with a capacity of 951 scfm each). The addition of two blowers, each with a capacity of 3,200 cfm would provide enough aeration capacity for the maximum day load at the future condition. Denitrification Concerns: As previously discussed, operations staff have expressed concerns with having the ability to denitrify at the future condition because of anoxic tank volume and nitrate recycle from the membrane tanks may have a high DO which could inhibit denitrification. Our calculations (as well as the original GE Zenon design calculations) and the plant data that we have been provided indicate that these two items would not be a problem. However, there are many variables that can affect the actual results. Therefore, to address this concern, we recommend gathering additional nitrate data and monitoring the results as flows and loads to the Surfside WWTF increase in the future. We have recommend budgeting for improvements to the nitrate recycle system in case future problems are encountered. The improvements would address the potential for high DO in the nitrate recycle by modifying the existing recycle from the membrane tanks with redirection to the aeration tanks and an additional, separate, nitrate recycle from the end of the aeration tanks to the anoxic tanks. 2.5.Disinfection 2.5.1.Current Operation and Performance The Facility O&M Manual indicates that the ultraviolet (UV) disinfection system operates with the UV dose automatically adjusted by the control system based on effluent flow and UV transmittance. It is our understanding that UV performance has been sufficient under current conditions. The data provided by the Surfside Operations Staff in a report titled, “Monthly Maximum Data Report” for the period from April 2010 to April 2011 indicates non-detect measurements for fecal coliform each month. 2.5.2.Capacity The UV system consists of two banks of UV lamps. Consistent with TR-16 requirements, each bank has the capacity for a peak hourly flow of 7.7 MGD (4.0 MGD maximum daily flow equivalent) with one bank offline. Based on the UV system manufacturer design information, the UV system can provide 65 percent UV transmittance at a peak hourly flow of 7.7 MGD at a 10 mg/l TSS concentration to meet a 200 FC/100 ml standard. 2.5.3.Recommendations There are no improvements required for capacity reasons. 2.6.Solids Processing 2.6.1.Current Operation and Performance At the time of our site visit (April 15, 2013 through April 17, 2013), primary sludge and waste activated sludge (WAS) from the ATS were being segregated. The primary sludge was going to the primary sludge holding tanks located at the primary treatment building and WAS was going to the advanced treatment building sludge holding tanks. The primary sludge and WAS were then 2014-07-02 Capacity Assessement Memo 18 July 2014 blended just prior to dewatering in the rotary presses. At the time of our visit, WWTF staff reported good dewatering performance. It is our understanding that WWTF staff have implemented Woodard & Curran’s recommendations to blend primary and WAS sludge without segregation. We also believe that this practice has not negatively affected dewatering capabilities. 2.6.2.Capacity We evaluated sludge storage capacity by developing a solids balance for the WWTF using the parameters described in Table 7 for the ATS. From this solids balance we determined that the solid processing system (storage tanks, pumping and rotary presses) has the capacity to handle the future condition. At the maximum monthly flow, we estimated the rotary presses would need to be operated at a flow rate of approximately 22 gallons per minute for 24 hours per week. 2.6.3.Recommendations As previously discussed, we recommend continuing with the on/off aeration operation of the sludge holding tanks to prevent anaerobic conditions from developing. 3.Summary of Findings, Recommendations, and Estimated Conceptual Cost The following is a summary of our findings: The projected future flow from the needs areas is 4.0 MGD on a maximum daily flow basis. With the addition of two blowers, the Surfside WWTF has sufficient capacity to receive and treat the projected future flow. The MassDEP groundwater discharge permit limit for flow to the groundwater discharge beds is 3.5 MGD which is less than the projected future flow. Therefore, expansion of the groundwater discharge capacity or revisions to the groundwater discharge permit are required. The expansion of groundwater discharge capacity for the Surfside WWTF would be required at the future condition even if Madaket and Warren’s Landing wastewater was not treated at the Surfside WWTF. Woodard & Curran and the Town have submitted the required documentation to MassDEP for this increased capacity and based on our discussions with MassDEP we understand that a revised discharge permit with the required flow increase will be issued soon. It is noted that the calculations for our capacity analysis were performed prior to the summer 2013 data being available. At the request of the Town, we subsequently evaluated the pollutant data for June to August of 2013 and found that the load data, when including this period, were consistent with the data used in our capacity analysis as summarized in the following table. Parameter Total Projected and Existing (Future Condition) Maximum Monthly Load (lbs/day) BOD5 11,000 TSS 9,000 Total Nitrogen 1,400 Our recommendations for improvements to the Surfside WWTF included the following: 2014-07-02 Capacity Assessement Memo 19 July 2014 Incorporate recommendations from the influent screening and corrosion control feasibility studies currently being performed. Consider installation of more reliable DO and ORP instrumentation to improved aeration control for the ATS. Installation of two additional blowers with a capacity of 3,200 cfm each will be required for the ATS at the future condition. Include a future capital budget item for improvements to the nitrate recycle system if problems with denitrification are encountered. We estimated the conceptual capital costs for our recommendations for additional blowers and the nitrate recycle system as summarized in the following table: Table 8: Conceptual Capital Cost Estimate Blower Addition Nitrified Recycle Construction $ 388,000 $ 371,000 Design Engineering, Permitting and Construction Administration $85,400 $ 81,600 Subtotal $ 473,000 $ 453,000 Contingency (30%)$ 142,000 $ 136,000 Project Total $ 615,000 $ 589,000 The estimate is based on the Engineering News Record (ENR) construction cost index of 9681 for February 2014. 980 Washington Street | Suite 325 Dedham, Massachusetts 02026 www.woodardcurran.com T 800.446.5518 T 781.251.0200 F 781.251.0847 MEMORANDUM TO:Kara Buzanoski, DPW Director and David Gray, Chief Operator FROM:Krista Forti and Jon Himlan DATE:September 11, 2014 RE:Influent Screening Alternatives Assessment Surfside WWTF, Town of Nantucket, Massachusetts 1.Introduction This memorandum describes Woodard & Curran’s conceptual analysis of the screenings alternative assessment for the Surfside WWTF. 1.1.Background/Existing Conditions The Surfside WWTF is located in the southwest region of Nantucket, MA and has a future peak hour design capacity of 7.7 million gallons per day (MGD) and an existing average daily flow of 1.23 MGD. Upgrades to the plant were completed in 2009 with the installation of a General Electric (GE) / Zenon membrane bioreactor (MBR) system. The current process train includes upstream of the include an aerated grit chamber, primary clarifiers, pre-anoxic tanks, aeration tanks, membrane filters, ultraviolet disinfection and groundwater disposal beds. An influent grinder was also installed during the 2009 upgrade, however due to severe hydrogen sulfide corrosion, the grinder is no longer functional and was removed. To evaluate this issue a screening analysis was conducted and documented in a memorandum entitled “Enhancements to the Surfside Wastewater Treatment Facility” by AECOM, dated January 9, 2012. The memorandum outlined the importance of MBR system pretreatment, identified pretreatment alternatives, and ultimately recommended the installation of a new grinder in the headworks to breakdown influent debris. Because they were interested in receiving a second opinion regarding the need for membrane pretreatment (screen versus grinder), the Town of Nantucket contracted Woodard & Curran to provide an Influent Screening Alternatives Assessment. 1.2.Scope The purpose of our screenings alternative assessment is to: a)Review existing documentation related to influent screening including design plans, operation and maintenance manuals, plant hydraulics, and the AECOM Memorandum dated January 9, 2012. b)Identify feasible screening alternatives and/or combinations of alternatives suitable for a membrane bioreactor treatment facility with primary clarifiers with the Surfside WWTF specific hydraulic and spatial requirements and operational needs. c)Provide a recommendation of the most desirable screening alternative with consideration given to process, cost, operation and maintenance concerns. d)Provide an opinion of probable cost for the recommended alternative including design, construction, engineering and contingency suitable for securing funding. 2014-09-11 Screening Alternatives Assessment Memo September 2014 1.3.Recommendation After analysis of multiple alternatives, as further described in the subsequent sections of this memorandum, Woodard & Curran recommends the installation of a new headworks consisting of two 6-mm screens, two 2- mm band screens, and two wash presses for screenings handling. We do not recommend installation of a grinder. 2.Review of Existing Documentation Woodard & Curran’s assessment was based on the following: The AECOM memorandum dated January 9, 2012 WWTF Operation and Maintenance (O&M) manuals WWTF record drawings GE/Zenon documentation and discussions with GE/Zenon representatives Discussions with screen manufacturers and review of their documentation Discussions with the Surfside WWTF operations staff; Industry technical publications such as the New England Interstate Water Pollution Control Commission’s Guides for Design of Wastewater Treatment Works, Technical Report 16, 2011 Edition (TR-16) and the Water Environment Federation (WEF) Manual of Practice No. 8 (MOP 8), 5th Edition. 3.Membrane Pretreatment Alternatives Evaluation Adequate pretreatment is essential to the stable, long-term operation of the membranes. Materials such as rags, paper, plastics, fibers, hair, and metals can accumulate on the membranes because they cannot pass through the pores of the membranes. These materials are likely to result in densely packed formations that will wrap around the membrane fibers and can break the fibers or reduce the available membrane filtering surface area. Membrane areas that are not blocked by such formations will have a higher loading/flow through them, making them more susceptible to fouling. The undesirable material can also plug or block the diffusers that provide scour air which is an important part of the membrane cleaning system. Providing pretreatment upstream of the membranes to remove the undesirable material will reduce the potential for damage and likely extend the membrane service life. Grinding and screening were the two pretreatment methods we evaluated for the purposes of the Alternative Assessment. 3.1.Grinding As a part of the 2009 upgrades, an in-channel grinder was installed at the headworks of the WWTF as a low-cost method to protect the membranes. According to the AECOM memo, the design intent was for the grinder to break down material at the influent of the plant. The AECOM memo also states that “the primary clarifiers are intended to function to remove objectionable materials prior to the membranes.” Although grinding may be beneficial upstream of certain pump applications to prevent clogging, TR-16 states that grinding is not a desirable option upstream of sensitive processes (such as membranes), due to re- aggregation of ground material. Through discussions with Surfside operations staff, we understand that when the grinder was in place, the ground up material did not fully settle out in the primary clarifiers and traveled into the membrane tanks (as well as the anoxic tanks, aeration tanks, and sludge holding tanks). Therefore, we have concluded that a grinder is not effective for membrane pretreatment because the ground up particles will still accumulate in the membrane tank and potentially damage the membranes. 2014-09-11 Screening Alternatives Assessment Memo September 2014 3.2.Screening Woodard & Curran recommends the installation of a 2-mm screen as a more effective approach to remove objectionable influent debris and better protect the membranes. Our recommendation is supported by the following: The Surfside WWTF GE/Zenon Operations & Maintenances (O&M) manual, Section 7.5.2 states that improper pre-screening can lead to difficulties in membrane cleaning and potential damage to the membranes. It also states that appropriate pre-screening with a 2 mm screen helps eliminate the build- up of trash, hair, lint and other fibrous materials and it decreases the risk of solids accumulation. TR-16, Chapter 5.1.1.3.4 states that downstream treatment processes such as MBRs require fine screening as low as 1 to 2 mm. To avoid excessive head loss and damage to very fine screens, multiple stages with screens of progressively smaller openings are typically required. MOP 8, Volume 2: Liquid Treatment Processes, Chapter 14, Section 6.4 discusses the importance of membrane pretreatment and states that fine screening equipment with a maximum of 1 to 2 mm openings is typically provided to protect membranes from debris and fibrous materials. It is also noted that the AECOM memo states that, “modifications to the existing Headworks to include screening were considered as part of the upgrade project but were ruled out in an effort to minimize project costs.” 4.Screening Alternatives Evaluation This section describes the screening alternatives and preliminary design criteria that we evaluated for the installation of a screen to protect the membranes. The parameters we considered included; type of screen, screen location, redundancy, screenings handling, and the need for enclosing the screen and associated equipment. 4.1.Type of Screen Four types of 2-mm screens were evaluated for the Surfside WWTF and we recommend the band screen. The advantages and disadvantages of installing each type of screen are listed in Table 4.1 below: 2014-09-11 Screening Alternatives Assessment Memo September 2014 Table 4.1: Types of Screens – Advantages & Disadvantages Screen Type Advantages Disadvantages Band Screen Recommended for MBR Pretreatment by screen manufacturers Small channel width required for installation Low screening carry-over Type of screen recommended by GE/Zenon for their MBR systems Requires additional wash press to minimize odor, collect organics, and reduce screen disposal costs In- Channel Rotary Drum Screen Recommended for MBR pretreatment by screen manufacturers Screenings washing and pressing is integral to the screen and a separate piece of equipment (wash press) is not required Low screenings carry-over Requires a wider channel than other alternatives Introduces higher headloss that other alternatives Perforated Plate Screen Small channel width required for installation High separation efficiency Reliable cleaning with the use of a rotating brush.  Requires additional wash press to minimize odor, collect organics, and reduce screen disposal costs Potential for screenings carry-over due to the screen moving in the direction of the flow Step/Stair Screen Small channel width required for installation Causes lower headloss than other alternatives Allows a pivot design for more convenient servicing of the unit above the channel Requires additional wash press to minimize odor, collect organics, and reduce screen disposal costs Potential for screenings carry-over due to the screen moving in the direction of the flow. We do not recommend the perforated plate and step/stair screens as most screening manufacturers who we contacted discouraged the use of a these alternatives for membrane protection. The perforated plate and step/stair screens have the potential for screenings carry-over due to the screen moving in the direction of the flow path. Band screens and rotary drum screens have an in-to-out flow pattern, which can prevent screenings carry-over and and the manufacturers offer zero by-pass screening warrantees . We recommend the installation of a band screen over the rotary drum screen because it is the type recommended in the GE/Zenon O&M manual and because it has a smaller footprint. 4.2.Screen Location We evaluated the following locations for the installation of the 2 mm screen: Upstream of the existing headworks in a new structure Within the existing headworks structure Downstream of the aerated grit chamber in a new structure Downstream of the primary clarifiers in a new structure Downstream of the pre-anoxic tanks within the existing advanced treatment structure Our evaluation of these locations included consideration of the following: 2014-09-11 Screening Alternatives Assessment Memo September 2014 Spatial Requirements: The new screen will need to be installed either within an existing structure or construction of a new structure will be required. Hydraulics: The new screen will add headloss and raise the water surface elevations upstream of its location. We assessed the effect of the screen location on plant hydraulics at the future peak hourly flow of 7.7 MGD. Screen Pretreatment Requirements: Depending on the location, a 6 mm screen may be needed to protect the 2 mm screen and allow it to operate more efficiently by reducing the potential for blinding and/or allowing bypass and carryover. Technical References such as TR-16 and MOP 8, as well as screen manufacturers such as Ovivo Water Technologies, Huber Technology, and Lakeside Equipment Corporation highly recommend the installation of coarser screen upstream of a 2 mm screen and the membranes. These references also stated that installing a 2 mm screen without pretreatment could cause premature wear and stress on the 2 mm screen, reducing the life of the screen by as much as 40% to 50%. Operation and Maintenance Benefits: In addition to protecting the membranes, depending on the location, the new screen may provide additional operation and maintenance benefits including protection of other plant equipment. These potential operation and maintenance benefits are important because operations staff report the following problems: Headworks valves are clogging with rags and plugging flow to the primary clarifiers. Rags are getting caught in the primary clarifier sprockets and derailing the sludge collection chains and flights. Rags are ground up in the primary sludge pump grinders and transferred to the sludge holding tanks where the ground up rags plug aeration diffusers and clog the decanters. The following table summarizes our evaluation the screen location alternatives. 2014-09-11 Screening Alternatives Assessment Memo September 2014 Table 4.2: Screen Location Alternatives Screen Locations Spatial Requirements Hydraulics Pretreatment Operation & Maintenance Upstream of Existing Headworks Sufficient land is available southeast of the existing headworks for the installation of a new influent channel and screen. There are no hydraulic restrictions. A 6-mm screen is required upstream of the 2-mm screen. Would resolve the ragging and clogging in the headworks, primary clarifiers, and primary sludge pumps.Existing Headworks A 2mm screen cannot fit within the existing influent channel at the headworks. The channel depth cannot accommodate the future peak hourly flows with the installation of a screen in this location. Downstream of Aerated Grit Chamber Space is limited and would likely require special/costly construction The additional headloss introduced at this location could be accomodated. Would resolve the ragging and clogging in the primary clarifiers and primary sludge pumps . Clogging in the existing headworks woud still be a problem. Downstream of Primary Settling Tanks This location has space available to install a fine screen but would eliminate the roadway and access between the disposal beds and the primary clarifiers and advanced treatment area. This location is somewhat hydraulically limited based on the primary effluent v- notch weir elevation at peak flow conditions. Modifications to the primary clarifiers would likely be required or short-term bypasses of the screen at peak hour flows would need to be allowed. Primary clarifiers would protect the 2- mm screen and a 6-mm screen would not be required. Problems with ragging and clogging in the headworks, primary clarifiers, and primary sludge pumps would remain. Downstream of Pre- Anoxic Tanks Modification of the existing anoxic tank/aeration tanks would be required which would likely require special/cost construction. The flow from the preanoxic tanks is pumped to aeration tanks, so there is a hydraulic break. The pumps would need to be replace with higher head models to overcome the additional losses introduced by the screen. Based on the criteria described above, Woodard & Curran recommends the installation of the 2 mm screen upstream of the existing headworks. Although this location would require the installation of a new structure and a 6 mm screen for pretreatment, it allows for the most flexibility spatially, has the least negative impacts on the plant hydraulics and provides the most operation and maintenance benefits. 2014-09-11 Screening Alternatives Assessment Memo September 2014 4.3.Redundancy It is common practice to recommend the installation of one duty and one standby piece of equipment for wastewater treatment process. Redundancy allows for the wastewater to be treated when equipment is down for maintenance or repair. TR-16 recommends the installation of multiple mechanically cleaned screens such that any one unit can be removed from service without sacrificing capability of the other screen to handle peak design flows. Therefore, Woodard & Curran recommends the installation of two 6- mm mechanical screens, and two 2-mm mechanical screens, each designed to handle the future peak hourly flow of 7.7 MGD. 4.4.Screenings Handling To handle the screenings that will be collected by the 2 mm and 6 mm screen, Woodard & Curran recommends the installation of a wash press to: Wash influent screenings to remove organic material from the screenings and return it to the wastewater flow. Returning organics to the wastewater stream reduces odor and handling hazards associated with the high concentrations of pathogens in the organic matter in screenings. The organics are also needed for the proper operation of the biological system downstream. Compact the influent screenings to reduce storage and disposal cost. Woodard & Curran recommends the installation of two wash presses. One shall be dedicated to the 6 mm screenings and one dedicated to the 2 mm screenings. Both wash presses will direct screenings into a common roll-off dumpster for disposal. 4.5.Enclosure Woodard & Curran recommends the installation of a building around the screening equipment for the following reasons: Protects the screens and associated equipment from freezing temperatures Protect the screens and associated equipment from salt air corrosion. Provides a means for containing and controlling potential odors. Protects the operators from the elements when they need to maintain or service the equipment. Our recommendation is based on the TR-16 recommendation that screening devices are located in weatherproof enclosures whenever possible. In addition, screen manufacturer representatives stated installing a screen without an enclosure is not recommended. 5.Recommendation Woodard & Curran’s recommendation includes the installation of screening equipment in a new headworks building upstream of the existing headworks, which includes 6-mm screening, 2-mm screening, and screenings handling. We also recommend that a new vortex grit removal system is incorporated into the new headworks as follows: 2014-09-11 Screening Alternatives Assessment Memo September 2014 Grit removal upstream of the 2mm screen will make screening more efficient. Incorporating the existing grit chamber into the flow path would be difficult and costly to construct because of the limited space between the existing headworks and the primary clarifiers. The existing grit chamber has significant hydrogen sulfide corrosion that would need to be repaired. Operations staff report concerns with the location of the grit screw mechanism as it is in the direct path of influent flow and is therefore vulnerable to wear from the grit in the influent wastewater. Note that due to relatively new grit pumps and grit washing equipment, our conceptual plan includes reuse of this equipment. A conceptual layout of the proposed headworks building is shown in the figure below. The force main shall be extended from the existing influent manhole to the new headworks. A Parshall flume will be located outside of the headworks building for the measurement of plant influent flow. The headworks building will house two parallel channels for the 6-mm screens, one channel for the vortex grit system, followed by two channels for the 2-mm screens. The wash presses (not shown in the figure) will be located behind and centered between the two 6-mm screens and two 2-mm screens, and will discharge screenings to the roll- off dumpster for storage and disposal. The 2-mm screen effluent will discharge into a pipe which will travel underground and adjacent to the existing headworks. A new distribution chamber will be installed to control the flow between the three primary clarifiers. New piping will be installed from the distribution chamber to the existing wall penetrations in the primary treatment building. The conceptual headworks design and layout includes the following: Two (2) 6mm band screens, each rated for 7.7 MGD. Two (2) 2-mm band screens, each rated for 7.7 MGD. Two (2) Wash presses (one dedicated to the coarse screens and one dedicated to the fine screens). Each wash press will contain a discharge header that travels approximately 20 feet to a dumpster One 10-foot diameter mechanical vortex grit removal system with a bypass channel Fourteen (14) Stainless Steel slide gates to isolate channels and unit processes One (1) Parshall flume located outside of the building, within a concrete channel (5) Ultrasonic level transducers to measure water level upstream of each screen as well as within the Parshall flume. One (1) concrete flow distribution structure (approximately 6’x6’) located downstream of the headworks facility to evenly split flow between the three existing primary clarifiers. One (1) cedar shingled building (approximately 41’x37’) to house the headworks equipment and channels, including HVAC, electrical, and plumbing connections. All concrete channels will be covered with heavy- duty grating. One (1) monorail system & hoist for the removal of equipment within the headworks building One (1) roll-up door for equipment and dumpster access into and out-of the building. One (1) 15 yard dumpster is recommended to be located inside of the building for the collection of dewatered screening material (wash press effluent). Approximately 10 feet of extension of the 20” influent force main Approximately 50 feet of 20” gravity pipe connecting the headworks effluent to the distribution structure Three (3) 16” pipes of approximately 35 feet long to connect the distribution structure to the three pipes at the primary treatment building wall. 2014-09-11 Screening Alternatives Assessment Memo September 2014 6.Opinion of Probable Cost The total project cost is estimated to be $4,970,000 which includes a thirty percent contingency. The total project costs are estimated in the table below: Total Project Cost Construction $3,136,000 Design & Engineering (10% of Construction Cost)$314,000 Permitting (4% of Construction Cost)$125,000 Construction Administration (8% of Construction Cost)$251,000 Sub-Total $3,826,000 Project Contingency (30%)$1,148,000 Project Total $4,970,000 The estimate based on the Engineering News Record (ENR) construction cost index of 9681 for February 2014. 1 P1203926.pdf CONTROL OF HYDROGEN SULFIDE CORROSION AT THE SURFSIDE WWTF Prepared for: WOODARD & CURRAN 980 Washington St., Suite 325 Dedham, MA 02026 by: BOWKER & ASSOCIATES, INC. CONSULTING ENGINEERS 477 Congress Street, Suite 1004 Portland, ME 04101 October, 2013 i EXECUTIVE SUMMARY INTRODUCTION The Surfside Wastewater Treatment Facility (Surfside WWTF) serves residential and commercial development on the island of Nantucket. The facility underwent a major upgrade in 2008. The headworks facility, which includes a comminutor and a grit chamber, has been subjected to severe corrosion caused by the presence of hydrogen sulfide (H2S) gas. The comminutor was destroyed by the corrosion and has been removed, but the concrete has also been attacked, exposing the aggregate in the concrete. In addition, odors from the headworks are strong due to elevated levels of H2S. In May of 2013, Bowker & Associates was retained by Woodard & Curran to investigate the severity and extent of the corrosion problem, characterize the wastewater in the collection system with regard to its propensity to generate and release hydrogen sulfide, and evaluate and recommend appropriate and economical alternatives for controlling the hydrogen sulfide. This report provides a description of the facilities, the results of a wastewater and headspace sampling program, an evaluation of hydrogen sulfide control alternatives, and recommendations. DESCRIPTION OF FACILITIES Wastewater Collection System The Nantucket wastewater collection system includes 11 pump stations and force mains. The largest pump station is the Sea St. Pump Station in “downtown” Nantucket. Approximately 70 percent of the total flow to the Surfside WWTF comes through this pump station. There are two force mains from Sea St., both 20-inch diameter, that are between three and four miles long. These two force mains manifold together with force mains from Surfside PS and South Valley PS before reaching the Surfside treatment plant. The average daily flow from Sea St. PS ranges from 0.6 to 1.4 mgd. At a flow of 1.0 mgd, the detention time in the force main is 7 or 8 hours depending on which force main is used. In general, force mains can be expected to generate sulfide when the sewage detention time exceeds two hours. Wastewater Treatment Facility The Surfside Wastewater Treatment Facility is an advanced wastewater treatment plant with an average daily design flow of 3.5 mgd. Current average flow ranges from approximately 0.9 to 1.9 mgd depending on season. Unit processes at the plant consist of comminutors (currently out of service due to corrosion), aerated grit chambers, primary clarifiers, aeration basins, membrane biological reactors, and ultraviolet disinfection system. Effluent is discharged into groundwater recharge basins. Solids handling processes include aerated sludge holding and rotary press dewatering. Dewatered sludge is landfilled or composted on the island. ii SAMPLING PROGRAM A sampling program was developed to 1) characterize the wastewater with regard to its propensity to generate and release hydrogen sulfide, and 2) quantify headspace H2S levels at various locations throughout the wastewater collection and treatment system. The program consisted of wastewater sampling at four locations in the collection system and plant headworks, and continuous monitoring of headspace H2S concentrations at five locations. The sampling program was conducted in May, 2013. EVALUATION OF SULFIDE CONTROL ALTERNATIVES Testing at the Nantucket WWTF showed relatively high levels of sulfide attributed to the 20-inch force main(s) from Sea St. Pump Station. The headworks of the plant exhibits severe corrosion. Although there is no apparent corrosion damage to the primary clarifiers, sufficient levels of headspace H2S exist to put the concrete tanks at risk for accelerated corrosion. For this reason, efforts were focused on reducing the sulfide in the wastewater entering the plant as a means to control corrosion due to hydrogen sulfide. Special considerations for any chemical used on the island of Nantucket include the following: 1. The cost of transportation to the island 2. Safety of the chemical (hazardous vs. non-hazardous) 3. Availability of access for chemical delivery and bulk storage Because the force main from Sea St. Pump Station generates the vast majority of sulfide entering the plant, a sulfide control chemical would need to be added at Sea St. PS in order to control formation in the main. Alternatives subjected to detailed evaluation included injection of magnesium hydroxide, calcium nitrate solution (Bioxide), sodium hypochlorite, and pure oxygen. CONCLUSIONS AND RECOMMENDATIONS Conclusions 1. The Surfside WWTP in Nantucket, MA has experienced severe corrosion of the headworks due to the presence of hydrogen sulfide gas. 2. Although the primary clarifiers do not exhibit obvious symptoms of hydrogen sulfide corrosion damage, the concrete is at risk for corrosion. 3. The majority of the sulfide entering the Surfside WWTF is formed in the force main from the Sea Street Pump Station, which is responsible for about 70 percent of the flow entering the plant. iii 4. Sulfide concentrations in the wastewater entering the plant were measured at 1 to 4 mg/L. Headspace H2S levels at the headworks averaged 36 ppm, which are very corrosive concentrations. Concrete pH was 2. 5. Although some hydrogen sulfide is returned to the headworks in the rotary press filtrate and the storage decant, the contribution is very low compared to that from the Sea Street force main. 6. Hydrogen sulfide headspace concentrations were low in the wet wells of Sea St. PS, Surfside PS and South Valley PS. There is little evidence of hydrogen sulfide corrosion at these locations. Recommendations 1. The headworks should be rehabilitated by high-pressure, water-blast cleaning of the concrete, removal of corrosion products, and application of a high-build, amine-cured epoxy that is resistant to attack by hydrogen sulfide and sulfuric acid. 2. The Town should conduct a trial injecting sodium hypochlorite at Sea St. to control sulfide generation in the force main. Effectiveness should be determined by monitoring headspace H2S at the headworks and measuring influent sulfide and chlorine residual in the wastewater. 3. If successful, bleach addition at Sea St. could be implemented as an interim solution to the hydrogen sulfide problem. 4. The Town should plan to implement a sidestream oxygen injection system as a permanent solution to corrosion and odor problems at the headworks. This will also ensure protection of the concrete in the primary clarifiers. The estimated capital cost of the system is $489,000, with annual O & M costs projected at $17, 500/yr. 5. The Town should collect and analyze influent WWTP samples for sulfide on a weekly basis, year-round, so that a data base can be developed. Currently, there is no information on sulfide loadings during winter months. Weekly samples should be collected at the same time (approx. 10 AM) and analyzed using the sulfide test kit provided to the Town. 6. The Town should consider purchasing a datalogging H2S analyzer for monitoring H2S concentrations in the headspace of the covered headworks and/or primary clarifiers. H2S levels should be monitored for one week per month for one year to document how levels fluctuate with seasons. The cost of a datalogging H2S analyzer is approximately $1,500. 7. Air flow rates in the two 4-inch air ducts from the headworks should be increased to a minimum of 150 cfm each. An air flow rate of 300 cfm will ventilate the covered space at 12 air changes per hour. It may be possible to adjust other dampers to increase the air flow, which is currently less than 200 cfm total. iv TABLE OF CONTENTS Page No. EXECUTIVE SUMMARY .............................................................................................................i 1.INTRODUCTION................................................................................................................... 1 2.DESCRIPTION OF FACILITIES........................................................................................... 3 2.1 Wastewater Collection System......................................................................................... 3 2.2 Wastewater Treatment Facility........................................................................................ 3 3.SAMPLING PROGRAM........................................................................................................ 7 3.1 Methodology.................................................................................................................... 7 3.2 Results.............................................................................................................................. 8 4.EVALUATION OF SULFIDE CONTROL ALTERNATIVES........................................... 16 4.1 Overview........................................................................................................................ 16 4.2 Economic evaluation...................................................................................................... 22 5.CONCLUSIONS AND RECOMMENDATIONS................................................................ 25 5.1 Conclusions.................................................................................................................... 25 5.2 Recommendations.......................................................................................................... 26 APPENDIX A: SAMPLING DATA APPENDIX B: OXYGEN INJECTION PROPOSAL v LIST OF TABLES Page No. Table 1 Detention Times in Sea St. Force Mains ................................................................5 Table 2 Average Daily Flows to Surfside WWTF by Month; 2012.....................................6 Table 3 Average Values of Sampling Data...........................................................................9 Table 4 Overview of Hydrogen Sulfide Control Techniques................................................18 Table 5 Daily Operating Cost of Screened Sulfide Control Alternatives...........................23 Table 6 Economic Analysis of Oxygen Injection vs. Chemical Addition..........................24 vi LIST OF FIGURES Page No. Figure 1 Photograph of Concrete and Metal Corrosion; Surfside WWTF Headworks....................................................................................2 Figure 2 Schematic of Nantucket Pump Stations and Force Mains.......................................4 Figure 3 H2S Concentration vs. Time, Sea Street PS Wet Well ..........................................10 Figure 4 H2S Concentration vs. Time, Surfside PS Wet Well.............................................11 Figure 5 H2S Concentration vs. Time, South Valley PS Wet Well......................................13 Figure 6 H2S Concentration vs. Time, Surfside WWTP Headworks...................................14 Figure 7 H2S Concentration vs. Time, Surfside WWTP Primary Effluent Channel............15 1 1.INTRODUCTION The Surfside Wastewater Treatment Facility (Surfside WWTF) serves residential and commercial development on the island of Nantucket. The facility underwent a major upgrade in 2008. The headworks facility, which includes a comminutor and a grit chamber, has been subjected to severe corrosion caused by the presence of hydrogen sulfide (H2S) gas. The comminutor was destroyed by the corrosion and has been removed, but the concrete has also been attacked, exposing the aggregate in the concrete. Figure 1 shows a photograph of the concrete corrosion. In addition, odors from the headworks are strong due to elevated levels of H2S. In May of 2013, Bowker & Associates was retained by Woodard & Curran to investigate the severity and extent of the corrosion problem, characterize the wastewater in the collection system with regard to its propensity to generate and release hydrogen sulfide, and evaluate and recommend appropriate and economical alternatives for controlling the hydrogen sulfide. This report provides a description of the facilities, the results of a wastewater and headspace sampling program, an evaluation of hydrogen sulfide control alternatives, and recommendations. 2 Figure 1. Photograph of Concrete and Metal Corrosion; Surfside WWTF Headworks 3 2.DESCRIPTION OF FACILITIES 2.1 Wastewater Collection System Figure 2 is a schematic diagram of the Nantucket wastewater collection system, showing the major pump stations and force mains. The largest pump station is the Sea St. Pump Station in “downtown” Nantucket. Approximately 70 percent of the total flow to the Nantucket WWTF comes through this pump station. There are two force mains, both 20-inch diameter. The “old” line is approximately 17,300 ft long, and the new force main is about 21,100 ft long. There is no set procedure or schedule for rotating the mains in and out of service, and there is no provision to drain the force mains. Note in Figure 2 that the force mains manifold together prior to reaching the plant, so there is no way to isolate or sample the individual force main discharges. Assuming Sea St. PS represents 70 percent of the total plant flow, the average daily flow from Sea St. PS is expected to range from 0.6 to 1.4 mgd. At an average dry weather flow from Sea St. PS of 1.0 mgd, the detention time in the force main is 7 or 8 hours depending on which force main is used. At low flow periods during late evening and early morning hours, wastewater detention time likely exceeds 12 hours. Table 1 shows estimates of detention times in the two force mains. In general, force mains can be expected to generate sulfide when the sewage detention time exceeds two hours. 2.2 Wastewater Treatment Facility The Surfside Wastewater Treatment Facility is an advanced wastewater treatment plant with an average daily design flow of 3.5 mgd (according to AECOM design manual). Current average flows range from approximately 0.9 to 1.9 mgd depending on season. Table 2 shows average daily flows for 2012. Average daily flows during the summer season can be over double the off- season flows. Unit processes at the plant consist of comminutors, aerated grit chambers, primary clarifiers, aeration basins, membrane biological reactors, and ultraviolet disinfection system. Effluent is discharged into groundwater recharge basins. Solids handling processes include aerated sludge holding and rotary press dewatering. Dewatered sludge is landfilled on the island. 4 SURFSIDE WWTF South Valley PS Airport PS Sea St. PS Surfside PS Pine Valley PS Sherburn Commons PS Abrem Quarry PS Aurora Way PS Cato Ln PS Monomy South. PS Monomy North PS 20” diam. 21,100 ft. (new) 20” diam. 17,300 ft. (old) 10” diam. 8,000 ft. 10” diam. 14,400 ft. Figure 2. Schematic of Nantucket Pump Stations and Force Mains 5 TABLE 1 DETENTION TIMES IN SEA ST. FORCE MAINS Detention Time, hr. Flow (million gal/day)Old FM1 New FM2 0.5 13.5 16.5 0.6 11.3 13.8 0.7 9.7 11.8 0.8 8.4 10.3 0.9 7.6 9.2 1.0 6.8 8.3 1.1 6.1 7.5 1.2 5.6 6.9 1.3 5.2 6.4 1.4 4.9 5.9 1.5 4.5 5.5 1 Old Force Main: 20” diameter; 17,300 ft. long 2 New Force Main: 20” diameter; 21,100 ft. long 6 TABLE 2 AVERAGE DAILY FLOWS TO SURFSIDE WWTF BY MONTH; 2012 Month Avg. Daily Flow, mgd Jan 0.91 Feb 0.87 Mar 0.86 Apr 0.94 May 1.29 June 1.44 July 1.84 Aug 1.93 Sept 1.34 Oct 1.09 Nov ? Dec ? 7 3.SAMPLING PROGRAM 3.1 Methodology A sampling program was developed to 1) characterize the wastewater with regard to its propensity to generate and release hydrogen sulfide, 2) quantify headspace H2S levels at various locations throughout the wastewater collection and treatment system. The program is described below. Liquid Stream Testing Wastewater samples were collected twice per day for three days from the following locations: 1. Sea St. PS wet well 2. Surfside PS wet well 3. South Valley PS wet well 4. Surfside WWTF influent Samples were analyzed in the field for the following parameters: 1. pH (Myron L Model 3P analyzer) 2. Oxidation-reduction potential (Myron L) 3. Temperature (Myron L) 4. Total sulfide (Chemetrics Sulfide Kit) Additional single grab samples were collected from: 1. Airport PS wet well 2. Sludge holding tank decant 3. Primary effluent channel 4. Rotary press filtrate 8 Hydrogen Sulfide Testing Datalogging H2S analyzers (OdaLogs) were deployed for up to two weeks to track hydrogen sulfide levels in the headspaces of the following pump stations and structures: 1. Sea St. PS wet well 2. Surfside PS wet well 3. South Valley PS wet well 4. Surfside WWTF influent channel after flume 5. Primary clarifier effluent channel 3.2 Results Table 3 is a summary of the collected data, showing the average values of the wastewater testing, as well as the range and average concentrations of H2S in the headspace. A tabulation of all wastewater data is included in Appendix A. Data are discussed below by location. Sea St. Pump Station Although the ORP of the incoming wastewater is negative, indicating septic conditions (no dissolved oxygen), no sulfide was detected in the samples. The pH was neutral at 7.1. As shown in Figure 3, no H2S gas was detected in the headspace of the wet well, and the average H2S concentration was 0 ppm. However, there is some evidence of corrosion at Sea Street PS, which may be due to low levels of H2S and poor ventilation. Surfside Pump Station Wastewater samples from the Surfside PS showed a more negative ORP (-122 mV) and an elevated pH of 8.1. The reason for the elevated pH is not clear, although Town staff suggested a car wash may be a source of alkaline discharges. However, only traces of sulfide were detected in the samples (up to 0.2 mg/L). Furthermore, headspace H2S levels were low, with a peak of 5 ppm and an average of 0.5 ppm. Figure 4 shows the H2S data. The higher pH of the wastewater 9 TABLE 3 AVERAGE VALUES OF SAMPLING DATA; Nantucket Sewerage System May 21 -23. 2013 Location pH s.u. ORP mV Temp, °C Total Sulfide mg/L Headspace H2S, ppm Range Average Wall pH Sea St. PS 7.1 -83 17.7 0.0 0 - 1 0 4 Surfside PS 8.1 -122 19.3 0.1 0 - 5 1 4 South Valley PS 8.1 -112 18.9 0.0 0 - 7 0 4 Surfside WWTP Headworks 6.9 -224 18.6 2.3 0 - 1674 36 2 Other locations (single sample) Airport PS 8.3 +64 19.8 0.0 - - - Sludge tank decant 7.2 -150 19.9 0.2 - - - Primary effl. channel 6.7 -210 17.8 2.0 0 - 237 4 3 Rotary press filtrate 5.4 -145 18.1 3.0 - - - 10 11 12 can have several benefits – the sulfide-producing bacteria prefer a neutral pH, so sulfide generation is suppressed, and the higher pH keeps any sulfide in solution so that it cannot be released as hydrogen sulfide gas. South Valley Pump Station Samples from South Valley Pump Station showed similar results to Surfside PS with an average pH of 8.1 and an average ORP of -112 mV. Headspace H2S averaged 0 ppm, with a peak of 7 ppm (see Figure 5). Again, the somewhat elevated pH likely helps suppress sulfide generation as well as prevent the release of H2S gas. Surfside WWTP Influent wastewater samples collected from the Surfside WWTF showed very low ORP of -224 mV, a pH of 6.9 and sulfide levels ranging from 0.8 to 4 mg/L. Hydrogen sulfide levels in the headspace ranged from 0 to 1,674 ppm, and averaged 36 ppm (see Figure 6). These are very corrosive levels of hydrogen sulfide gas. Concrete pH was approximately 2 due to the biological conversion of H2S to sulfuric acid. On May 22, the “new” force main was placed into operation, and the septic wastewater in the line was pumped to the plant. As can be seen in Figure 6, this resulted in a major spike in wastewater sulfide and resulting headspace H2S. The wastewater sample collected showed sulfide levels of 4 mg/L and had high grease and solids content. During this time, headspace H2S reached its peak of over 1,600 ppm. NOTE: H2S concentrations above 300 ppm are considered an imminent life threat. A single wastewater sample was collected from the primary effluent channel on the final day of sampling. Results were similar to those for the plant influent. Total sulfide was 2 mg/L. Average headspace H2S in the effluent channel was 4 ppm, with a peak of 237 ppm on May 22 when the idle force main was brought on-line (see Figure 7). Concrete pH was approximately 3. 13 14 15 16 Although the primary clarifiers show little obvious corrosion damage, the concrete is considered to be at risk for corrosion due to the presence of sulfide in the wastewater. Miscellaneous Locations Grab samples of wastewater were collected and analyzed from the Airport PS, the sludge decant line, and the filtrate from the rotary sludge press. The press filtrate had a sulfide content of 3 mg/L, with low pH of 5.4 and ORP of -145 mV. Although the sulfide level is relatively high, the flow rate of filtrate is very low compared to the influent flow. The rotary press filtrate is not considered a significant contributor of sulfide to the plant headworks. The sludge holding tank decant line showed a sulfide concentration of only 0.2 mg/L, and is not a major source of sulfide. Headworks Air Flow Measurements Poor ventilation of enclosed spaces can often exacerbate hydrogen sulfide corrosion by allowing build-up of high, corrosive concentrations of H2S gas. Although ventilation alone is unlikely to prevent corrosion, it is recommended in order to control headspace H2S concentrations. Two 4-inch diameter ducts serve the headworks. Air flow measurements showed approximately 125 cfm in the northwest duct, and 70 cfm in the southeast duct, for a total of 195 cfm. Based on the volume of the headspace below the covers, this flow rate corresponds to an air exchange rate of 8 air changes per hour. The channels and grit chamber should be ventilated at a minimum of 300 cfm, which is the design air flow from the headworks (based on 12 air changes per hour) 4.EVALUATION OF SULFIDE CONTROL ALTERNATIVES 4.1 Overview Testing at the Nantucket WWTF showed relatively high levels of sulfide attributed to the 20-inch force main(s) from Sea St. Pump Station. The headworks of the plant exhibits severe corrosion. 17 Although there is no apparent corrosion damage to the primary clarifiers, sufficient levels of headspace H2S exist to put the concrete tanks at risk for accelerated corrosion. Concrete pH at the effluent channel was 3. For this reason, efforts are focused on reducing the sulfide in the wastewater entering the plant as a means to control corrosion due to hydrogen sulfide. There are a number of chemicals that can be added to wastewater to oxidize, precipitate, or prevent the formation of sulfide. These are summarized in Table 4. Special considerations for any chemical used on the island of Nantucket include the following: 1. The cost of transportation to the island 2. Safety of the chemical (hazardous vs. non-hazardous) 3. Availability of access for chemical delivery and bulk storage Because the force main from Sea St. Pump Station generates the vast majority of sulfide entering the plant, most likely a sulfide control chemical would be added at Sea St. PS in order to control formation in the main. There are several options listed in Table 4 that are not considered viable for this application. These are discussed below: Hydrogen peroxide and potassium permanganate - These chemicals are only effective for removing existing sulfide, not preventing its formation. Hydrogen peroxide is too costly to be used as a source of oxygen to prevent sulfide generation. The chemicals would have to be added about 10 to 20 minutes flow time upstream of the WWTF at a remote chemical feed station. The chemicals are hazardous. Air injection- The detention time in the force main is too long to make air injection a viable alternative. Unless air were to be injected at multiple locations along the force main, it would be impossible to maintain aerobic conditions and prevent sulfide formation, particularly during low- flow periods. 18 TABLE 4 OVERVIEW OF HYDROGEN SULFIDE CONTROL TECHNIQUES Technique Frequency of Use Advantages Disadvantages I.OXIDATION Air injection Low Low cost, adds DO to wastewater to prevent sulfide generation Applicable only to force mains; potential for air binding; limited rate of O2 transfer Oxygen injection Low 5 times solubility of air; high DO possible; economical for force mains Applicable only to force mains; requires on-site generation or purchase as liquid O2 Hydrogen peroxide Medium Effective for sulfide control in gravity sewers or force mains; simple installation Costs can be high to achieve low (<0.5 mg/L) sulfide; safety Sodium hypochlorite High Applicable to gravity sewers or force mains; effective for broad range of odorants Safety considerations; high chemical costs Potassium permanganate Medium Effective, powerful oxidant; good for sludge handling applications High cost, difficult to handle II. PRECIPITATION Iron salts High Economical for sulfide control in gravity sewers or force mains Does not control non-H2S odors; sulfide control to low levels may be difficult; increased sludge production III. pH ELEVATION Sodium hydroxide (shock dosing) Medium Intermittent application; simple, little equipment required Does not provide consistent control; safety considerations Magnesium hydroxide Low Maintains pH at 8–8.5; adds alkalinity; economical for high (>5 mg/L) sulfide levels; safe Requires mixer to maintain slurry in suspension; cost is independent of sulfide concentration IV. PREVENTION Nitrate formulations High Can be used to prevent sulfide generation or oxidize sulfide in gravity sewers and force mains; safe to handle Dosages vary depending on use: prevention vs. removal Anthraquinones Low Prevents sulfide generation biochemically by disrupting sulfur cycle Not well developed; results inconsistent and difficult to predict 19 Sodium hypochlorite - Sodium hypochlorite is a powerful disinfectant that can be dosed into a force main to prevent the bacteria from producing sulfide. However, the chemical is hazardous, and a bulk storage tank of a hazardous chemical at the Sea St. Pump Station is likely to meet with resistance from neighbors. However, the plant receives sodium hypochlorite in bulk. Ferrous chloride - Ferrous chloride is a corrosive chemical that causes the sulfide to be precipitated as a solid, preventing release of hydrogen sulfide gas. It is a hazardous chemical with a pH of <2 and storage of this material at the Sea St. PS is not considered appropriate. The following alternatives are considered for further evaluation because of their proven effectiveness and non-hazardous nature: 1. Oxygen injection 2. Nitrate addition 3. Magnesium hydroxide addition For comparison purposes, sodium hypochlorite was included in the analysis because the plant currently purchases bulk chemical for use in the chemical scrubber odor control system. The four alternatives are discussed below. 1.Oxygen Injection Because pure oxygen is five times more soluble in water than air, it is possible to achieve higher DO levels in sewage by injecting pure oxygen instead of air. Pure oxygen may therefore be a more effective method of sulfide control for cases where the total oxygen requirement exceeds that which can be transferred using air injection. Use of pure oxygen as a sulfide control measure is particularly advantageous in pressurized systems (force mains) because dissolution of oxygen is greater at higher pressures. Since less oxygen gas is required than air to achieve the desired DO levels, the potential for gas pocket generation in force mains is substantially reduced. The initial oxygen dosage is dependent on the oxygen uptake rate of the wastewater, the uptake 20 by the slime layer, the detention time in the force main, and the concentration of dissolved sulfide. Pure oxygen systems historically have included a liquid oxygen storage vessel, vaporizer, pressure regulator, oxygen feed and injection systems, and a control system. The oxygen storage vessel, vaporizer, and pressure regulator are normally leased from an oxygen supplier. Within the past 15 years, small, skid-mounted on-site oxygen generation systems using pressure swing absorption (PSA) or vacuum swing absorption (VSA) technology have become available at relatively low cost, making on-site generation attractive for pump station applications. Oxygen can be injected: 1) in a pressurized side stream that is mixed with the main flow, 2) through a U- tube oxygen dissolver that increases dissolution of oxygen under pressure created by the raw sewage pumps, or 3) directly into a force main at the pump discharge. A proprietary sidestream oxygen dissolver is now being marketed for sulfide control in force mains. It can use atmospheric air or oxygen from an on-site PSA/VSA unit. These systems have an excellent track record for preventing sulfide formation in force mains. 2.Nitrate addition Use of sodium nitrate and formulations containing nitrate and nitrite have been successfully used for sulfide control. The presence of nitrate suppresses sulfide generation because anaerobic bacteria preferentially use the nitrate ion before sulfate as a source of oxygen. In addition, nitrate promotes the biological oxidation of sulfide if sulfide is already present. Use of nitrate has become very popular for sulfide control applications. At the proper dosage, it can be effective for both preventing sulfide generation and removing existing sulfide. The theoretical dosage for prevention is 9.3 lb NO3 per lb sulfide, and for oxidation, 3.1 lb NO3 per lb sulfide. For the proprietary calcium nitrate product Bioxide™, this translates into theoretical chemical requirements of 2.1 gal/lb S and 0.7 gal/lb S, respectively. One advantage that is at least partially responsible for its popularity is the non-hazardous nature of the chemical. Equipment typically consists of a bulk storage tank, metering pumps, and a timer to step up the dosage rate during times of peak diurnal sulfide concentrations. 21 3.Magnesium hydroxide addition A chemical that is relatively new to the odor/corrosion control market is magnesium hydroxide. A magnesium hydroxide slurry (approximately 58% Mg(OH2) is added to the wastewater to achieve a pH of about 8.5. This shifts the hydrogen sulfide equilibrium from dissolved hydrogen sulfide gas (which is easily stripped from solution) to hydrosulfide ion, which cannot be released. The dosage required to achieve pH 8.5 is a function of the pH and alkalinity of the wastewater and is independent of the sulfide concentration. Dosages of Mg(OH)2 solution typically range from 50 to 100 gal per million gallons of wastewater. According to one vendor, it is more economical than other chemicals when the sulfide levels approach 5 mg/L. For long force mains with long detention times, use of magnesium hydroxide may be an economical solution to sulfide control. Equipment consists of a storage tank with a mixer to maintain the slurry in suspension, and a metering pump, preferably flow-paced. Magnesium hydroxide (milk of magnesia) is non- corrosive and safe to handle. 4.Sodium hypochlorite injection Chlorine will oxidize sulfide to sulfate or to elemental sulfur, depending on pH. It is typically added at a dosage rate of 10 to 15 lb Cl2 per lb H2S removed. The stoichiometric weight ratio is 8.9:1 to oxidize sulfide to sulfate according to the following reaction: 4Cl2 + HS-+ 4H2O SO42-+ 9H++ 8Cl- However, observed dosage ratios for force main applications may be as low as 5:1, possibly due to a disinfection effect on the slime layer. This has been observed by Bowker & Associates as well as other practitioners. Chlorine is typically added as an aqueous solution (sodium hypochlorite) due to safety concerns of storing and feeding gaseous chlorine, particularly in residential or commercial areas. Sodium hypochlorite is a hazardous chemical, and must be handled accordingly. 22 4.2 Economic evaluation Table 5 is a comparison of the daily cost of various chemicals that could be added at the Sea Street Pump Station to control sulfide generation. These estimates are based on measured sulfide loadings in May 2013, field experience with dosage rates, and vendor quotes for chemical delivered to Nantucket. It is likely that during winter months, chemical requirements would be reduced below the estimated dosages due to colder wastewater temperature. However, it is also possible that dosages could exceed the estimates during peak summer months of July, August, and September. The table shows oxygen to have the lowest daily cost of any of the chemical control alternatives, with a daily cost that is 75 percent lower than other chemicals, even when using a relatively high unit oxygen cost of $0.10/lb. However, the equipment necessary to generate and dissolve the oxygen is considerably more expensive that a simple chemical storage tank and metering system. After oxygen, the least expensive chemical is sodium hypochlorite at a projected cost of $195/day, followed by magnesium hydroxide and calcium nitrate. Table 6 is an economic analysis of oxygen injection vs. chemical addition for the Sea Street force main. As can be seen, the capital cost for the oxygen system is significantly greater than the capital cost of the chemical metering system. However, the low operating cost for oxygen results in an annualized cost that is approximately 30% lower than the chemical addition system. Therefore, oxygen injection represents the most cost-effective and reliable long-term strategy for controlling hydrogen sulfide corrosion at the Surfside WWTF. At the current price of $1.30/gal for bulk purchases of sodium hypochlorite, this chemical is competitive with other sulfide control chemicals, and appears to be the lowest cost chemical. Daily usage is estimated to be 150 gal/day, equating to a daily cost of about $200/day, or nearly $75,000/yr. According to plant staff, the town has the capability to transfer bleach from the bulk storage tank at the Surfside WWTF to a smaller tank located at the Sea St. PS. Disadvantages of sodium hypochlorite include 1) it is a hazardous chemical, requiring proper safety equipment and procedures when handling, and 2) overdosing could cause a biological upset at the plant. 23 TABLE 5 DAILY OPERATING COST OF SCREENED SULFIDE CONTROL ALTERNATIVES -Nantucket, MA – Chemical Dosage Basis Chemical Consumption1 Unit Price Daily Cost1 Calcium nitrate (BioxideTM)3 gal/lb S 100 gal/d $3.35/gal $335 Magnesium Hydroxide 100 gal per Million 100 gal/d $2.05/gal $265 Oxygen 10 mg/L-hr uptake rate 700 lb/d $0.10/lb $70 Sodium hypochlorite 5 lb Cl2 per lb S 150 gal/d $1.30/gal $195 1 Daily chemical consumption will vary depending on seasonal wastewater temperatures, flow rate, and BOD. Estimates reflect sulfide loadings measured in May, 2014. 24 TABLE 6 ECONOMIC ANALYSIS OF OXYGEN INJECTION VS. CHEMICAL ADDITION - Nantucket, MA - Oxygen Injection Chemical Addition1 CAPITAL COST, $ 1.Site work/mobiliz.$ 10,000 $ 10,000 2.Equipment 270,000 25,000 3.Installation 81,000 20,000 4.Eng’r’g. & conting. @ 35%126,000 19,000 Total Capital Cost $489,000 $ 74,000 O & M COST, $/yr 1.Chemicals --$ 73,000/yr 2.Power @ $0.12/kwh $ 15,000 200 3.Maintenance 2,500 1,000 Total O & M Cost $ 17,500/yr $74,200/yr ANNUALIZED COST 1.Annualized capital (20 yr @ 5%) $ 39,200 $ 5,900 2.O & M 17,500 74,200 Total Annualized Cost $ 56,700/yr $ 80,100/yr 1 Chemical is assumed to be sodium hypochlorite for this analysis 25 Sodium hypochlorite dosage should be flow-paced to prevent overdosing and to maintain the necessary concentration to control sulfide generation. 5.CONCLUSIONS AND RECOMMENDATIONS Based on analysis of data collected from the Nantucket collection system and Surfside WWTP, and the evaluation of alternatives to control hydrogen sulfide corrosion, the following conclusions and recommendations are presented. 5.1 Conclusions 1. The Surfside WWTP in Nantucket, MA has experienced severe corrosion of the headworks due to the presence of hydrogen sulfide. 2. Although the primary clarifiers do not exhibit obvious symptoms of hydrogen sulfide corrosion damage, the concrete is at risk for corrosion. 3. The majority of the sulfide entering the Surfside WWTF is formed in the force main from the Sea Street Pump Station, which is responsible for about 70 percent of the flow entering the plant. It was not possible to sample the other contributing force mains, since they manifold into the force main from Sea St. 4. Sulfide concentrations in the wastewater entering the plant were measured at 1 to 4 mg/L. Headspace H2S levels at the headworks averaged 36 ppm, which are very corrosive concentrations. Concrete pH was 2. 5. Although some hydrogen sulfide is returned to the headworks in the rotary press filtrate, the contribution is very low compared to that from the Sea Street force main. 26 6. Hydrogen sulfide headspace concentrations were low in the wet wells of Sea St. PS, Surfside PS and South Valley PS. There is little evidence of hydrogen sulfide corrosion at these locations. 5.2 Recommendations 1. The headworks should be rehabilitated by high-pressure, water-blast cleaning of the concrete, removal of corrosion products, and application of a high-build, amine-cured epoxy that is resistant to attack by hydrogen sulfide and sulfuric acid. 2. The Town should conduct a trial injecting sodium hypochlorite at Sea St. to control sulfide generation in the force main. Effectiveness should be determined by monitoring headspace H2S at the headworks and measuring influent sulfide and chlorine residual in the wastewater. 3. If successful, bleach addition at Sea St. could be implemented as an interim solution to the hydrogen sulfide problem. The cost to control sulfide using bleach is estimated at $73,000/yr. 4. The Town should plan to implement a sidestream oxygen injection system as a permanent solution to corrosion and odor problems at the headworks. This will also ensure protection of the concrete in the primary clarifiers. The estimated capital cost of the system is $489,000, with annual O & M costs projected at $17, 500/yr. 5. The Town should collect and analyze influent WWTP samples for sulfide on a weekly basis, year-round, so that a data base can be developed. Currently, there is no information on sulfide loadings during winter months. Weekly samples should be collected at the same time (approx. 10 AM) and analyzed using the sulfide test kit provided to the Town. 6. The Town should consider purchasing a datalogging H2S analyzer for monitoring H2S concentrations in the headspace of the covered headworks and/or primary clarifiers. H2S levels should be monitored for one week per month for one year to document how levels fluctuate with seasons. The cost of a datalogging H2S analyzer is approximately $1,500. 27 7. Air flow rates in the two 4-inch air ducts from the headworks should be increased to a minimum of 150 cfm each. An air flow rate of 300 cfm will ventilate the covered space at 12 air changes per hour. It may be possible to adjust other dampers to increase the air flow, which is currently less than 200 cfm total. 28 APPENDIX A: SAMPLING DATA 29 TABLE A-1 LIQUID SAMPLING DATA NANTUCKET PUMP STATIONS AND WWTP May 21, 2013 Location Time pH, s.u. ORP, mV Temp, °C Total Sulfide mg/L Sea St. PS 9:30 7.1 -75 16.8 0.0 South Valley PS 10:40 8.2 -79 19.7 0.0 Surfside PS 11:25 7.9 -165 20.3 0.2 Airport PS 11:05 8.3 +64 19.8 0.0 Surfside WWTP 11:50 7.3 -245 19.8 2.5 Sludge tank decant 1:40 7.2 -150 19.9 0.2 Sea St. PS 2:15 7.1 -70 20.7 0.0 South Valley PS 3:00 7.6 -145 19.3 0.0 Surfside PS 3:30 8.0 -120 19.8 0.1 Surfside WWTP 3:50 6.8 -260 18.4 2.0 30 TABLE A-2 LIQUID SAMPLING DATA NANTUCKET PUMP STATIONS AND WWTP May 22, 2013 Location Time pH, s.u. ORP, mV Temp, °C Total Sulfide mg/L Sea St. PS 8:40 7.2 -95 15.4 0.0 Surfside PS 9:10 8.2 -65 18.4 0.0 South Valley PS 9:30 8.5 -155 17.6 0.0 Surfside WWTP 10:10 6.3 -220 18.0 4.0 Primary effluent channel 11:10 6.7 -210 17.8 2.0 Rotary press filtrate 11:55 5.4 -145 18.1 3.0 Sea St. PS 1:20 7.1 -110 18.8 0.0 South Valley PS 2:20 7.8 -130 19.3 0.0 Surfside PS 2:45 8.2 -120 18.4 0.0 Surfside WWTP 3:30 6.9 -155 18.0 0.8 31 TABLE A-3 LIQUID SAMPLING DATA NANTUCKET PUMP STATIONS AND WWTP May 23, 2013 Location Time pH, s.u. ORP, mV Temp, °C Total Sulfide mg/L Sea St. PS 8:15 7.2 -65 16.9 0.0 So. Valley PS 8:45 8.4 -50 18.7 0.0 Surfside PS 9:30 8.2 -140 19.8 0.0 Surfside WWTP 11:00 7.2 -240 18.8 2.0 Primary effluent 12:10 7.0 -70 18.9 0.0 32 APPENDIX B: OXYGEN INJECTION PROPOSAL 33 Odor and Corrosion Control By SuperOxygenation Nantucket, MA Sea St. Pump Station July 1st , 2013 34 July 1, 2013 Bob Bowker Bowker and Associates Portland, ME PROJECT: Nantucket, Sea St. PS and FM Dear Bob: ECO2 is pleased to provide you with a design and proposal for a SuperOxygenation System that will raise the D.O. level in the Sea Street force main to prevent anaerobic conditions and the formation of sulfides. Assuming 47psi of pressure under continuous VFD operation, the D.O. in the discharge of the ECO2 Cone can be raised to 114mg/L. At an oxygen uptake rate (OUR) of 10mg/L/hr, this will maintain aerobic conditions for approximately 11 hours, sufficient for treatment of the old force main and only a couple of hours short for low winter flows in the new force main. It may be possible that the oxygen uptake rate during the winter is lower than 10mg/L/hr, which would extend the reach of the D.O. level. Typically, sulfide production is down during the winter months and often receptors aren’t as sensitive during the winter months (fewer people that are mainly inside). The ECO2 System would be able to reliably prevent sulfide formation and the associated odors and corrosion, during the higher flows during the summer months and for most of the time during the winter months. We thank you for the opportunity to provide a proposal. Please contact us with any questions you may have. We look forward to working with you on this project. Best regards, Inken Mello Inken Mello Director of Sales & Marketing Eco Oxygen Technologies, LLC Phone: 858-272-7102 e-mail:imello@eco2tech.com 35 I. ECO2 SYSTEM DESCRIPTION ECO2 System Design ECO2’s technology is based on Henry’s Law and works by trapping pure oxygen bubbles inside the ECO2 cone until they are dissolved. The system operates by pumping a side stream of water through a conical shaped oxygen transfer reactor, also known as the Speece Cone. Gaseous oxygen is fed into the cone and broken up into an intense bubble swarm by the velocity of the wastewater. The cone shape design provides sufficient contact time for the oxygen to fully dissolve in the water. The cone achieves an average oxygen transfer efficiency of 95%. Odor Control with ECO2 Sulfides are produced by Sulfate Reducing Bacteria only under anaerobic conditions in a sewer. By adding a sufficient amount of D.O. to the sewer, the ECO2 System maintains aerobic conditions and with this, PREVENTS the formation of sulfides and H2S in the sewer. The results are consistently near non-detect levels of H2S at the discharge of the force main. Corrosion Control with ECO2 When gaseous H2S reaches the surface of the sewer infrastructure, Thiobacillus thiooxidans bacteria oxidize H2S to sulfuric acid (H2SO4), which quickly and tenaciously corrodes concrete and steel. According to the ASCE Manual for manhole rehab, H2S concentrations of 20ppm corrode concrete at a rate of 1 inch per 5 years. It is therefore crucially important to not just reduce sulfide concentrations, but to eliminate the formation of sulfides, in order to achieve effective corrosion control. 36 II. ECO2 BASIS OF DESIGN The design is based on data provided by you as outlined in the table below. The design accounts for 1mg/L existing sulfides in the wastewater, an oxygen uptake rate of 10mg/L/hr and a slightly positive DO at the discharge. Force Main Sea St. PS Average Flow (gpm)350 Force Main Length (ft)21,000 Force Main Diameter (inches)18 Static Head- assumed (ft of head)80 TDH (ft of head)108 Fill/Draw or Continuous Operation Continuous Maximum HRT (hrs)11 Existing Dissolved Sulfides (mg/L)1 Required amount of O2per day (lbs/day)700 ECO2 System Size (ft dia.)3 Flow Rate through ECO2 System (gpm)450 HP of side stream pump (HP)7 ECO2 System Construction The ECO2 System consists of a hollow, stainless steel cone with no internal mixers, baffles or moving parts. The influent and effluent pipes are a minimum of 4’’ diameter, capable of passing dirty wastewater without clogging. The dish-shaped bottom with the discharge pipe at the low point provides for a self-cleaning device with no need for maintenance. The ECO2 System has a life expectancy of 20+ years.The oxygen feed is fully automated. The only moving part is the side stream pump that requires standard maintenance. 37 III. ECO2 PROPOSAL Capital Cost The Sea St. Force Main requires a 3ft diameter ECO2 System to add the appropriate amount of oxygen to the force main. The system is equipped with a PLC controlled oxygen flow control system that fully automates the oxygen feed rate depending on the actual force main flow. A 10HP sidestream pump is required to pump a continuous sidestream through the ECO2 System. Capital Cost ECO2 System Sea St. PS System includes: ECO2 System 195,000 PLC Oxygen Flow Control System Incl. Side Stream Pump (Estimate)10,000 Oxygen Generator (Estimate)65,000 Total Capital Cost ECO2 System $270,000 Quote is valid for 90 days. Anticipated O&M Costs The system operates a sidestream pump that requires standard maintenance. The electrical draw for the pump is 7HP (450gpm). The oxygen generator generates oxygen on demand. It is operated on a VFD and will automatically turn down when the demand is low, resulting in a very energy efficient operation. Operating Cost ECO2 System Sea St. PS Side Stream Pumping (7 HP)*4,700 Electricity for O2 Generator ( 213 kWhr/day)*7,800 O&M (20%)2.500 Annual O&M Cost ECO2 System $15,000 * Cost of power assumed at $0.10/kWhr 38 IV. ECO2 GUARANTEE Experience ECO2 has over 10 years of experience in the design, assembly, start-up and operation of SuperOxygenation Systems. ECO2 brought the SuperOxygenation Technology to the wastewater market for odor and corrosion control with our first three systems installed in 2003. By now we have over 30 installations across the U.S. that are all running successfully. We’re happy to share our installation list with you and have you talk to any of our clients. The ECO2 Approach to Successful Installations We have gained valuable experience in the design of our systems for various applications. Especially force main applications can get very complicated and the SuperOxygenation Technology is not always a technical fit. We recognize the limitations of our systems and share these with our clients before we get into a project. We will not waste your time or money with extended pilot tests or trial and error installations. If you receive a quote from us, we know that our design will work and we will guarantee our design. ECO2 Performance Guarantee ECO2 will provide a Performance Guarantee based on the provided data. ECO2 will provide performance monitoring until the system is dialed in and operating according to the design specifications. 39 V. OXYGEN SOURCE Oxygen can either be generated on-site or delivered to the site as liquid oxygen (LOX) by a local gas supplier. ECO2 is available to help evaluate the various oxygen sources depending on site specifics and client preferences. For this particular project, ECO2 recommends a VSA On-Site Oxygen Generator. VSA On-Site Oxygen Generation ECO2 has been successful working with PCI out of Riverside, CA using their vacuum swing adsorption (VSA) oxygen generators. VSA systems use a reversible blower system to generate oxygen at low pressure and then compress only the 21% of oxygen that have been removed from the air, as opposed to PSA oxygen generators that compress 100% of the air with an air compressor. VSA Systems are therefore much more energy efficient. Furthermore, a VSA System employs fewer parts, making it a more reliable oxygen source than PSA Systems. A Spec Sheet of the proposed oxygen generator is attached to this proposal. 40 VI. COMPETITIVE ADVANTAGES 95% Transfer Efficiency Every ECO2 System is tested for its transfer efficiency at start-up. The average transfer efficiency that has been documented on our systems is 95%. This is important because: Oxygen costs money, any oxygen that is not dissolved is wasted money. Systems with a lower transfer efficiency need to make up for it in size or they will not have the same results. No Bubbles The ECO2 System dissolves the oxygen bubbles outside of the force main in the cone. The bubbles are trapped in the cone until they are dissolved. Basically no gaseous oxygen enters the force main. This is important because: Gaseous oxygen is not available to the microorganisms as an oxygen source Gaseous oxygen will rise to the crown of the pipe and create a potentially hazardous headspace in the sewer Gaseous oxygen is either lost through air release valves or may air lock the pipe or pumps. No small openings All openings on every ECO2 System are a minimum of 4’’ in diameter, capable of passing dirty wastewater without clogging. This is important because: A system with small openings such as nozzles or venturis is prone to clogging and is therefore not a reliable odor control technology Small openings will clog and require constant attention and maintenance, raising the O&M costs and wasting valuable man-power. Chopper or grinder pumps may alleviate the problem, but they add another piece of equipment to the maintenance cycle and require additional horse power. They are also designed to pass particles through the pump itself, not necessarily small openings downstream of the pump. 10 Years of Experience ECO2 has over 10 years of experience in the design, assembly, start-up and operation of SuperOxygenation Systems. ECO2 brought the SuperOxygenation Technology to the wastewater market for odor and corrosion control with our first three systems installed in 2003. By now we have over 30 installations across the U.S. that are all running successfully. But don’t take our word for it. Ask for our installation list and have our happy customers validate our claims. VII. TERMS & CONDITIONS Page 1 of 23 Memorandum AECOM 250 Apollo Drive Chelmsford, MA 01824 www.aecom.com 978.905.2100 tel 978.905.2101 fax Table of Contents 1. Influent Screening ............................................................................................................................... 3 1.1 Band Screen ........................................................................................................................ 4 1.2 Inclined Screen .................................................................................................................... 6 1.3 Installation Location Options ............................................................................................... 9 1.4 Evaluation .......................................................................................................................... 18 2. Vacuum Truck Discharge Connection and Location ........................................................................ 20 3. Miscellaneous Items ......................................................................................................................... 21 The Surfside Wastewater Treatment Facility (WWTF) is located on South Shore Road in the southwest region of Nantucket and has a design capacity of 3.5 million gallons per day (mgd). Upgrades to the Facility were completed in 2009. The facility has been operating very well since it went on-line, consistently meeting its effluent permit limits. The operations staff has identified several improvements that they feel may result in more efficient operations and/or result in better control flexibility on the performance of the facility. Suggestions for operational enhancements offered by a plant’s operations staff are typical after having several years of operational data and experience history. While improvements can make a difference in a plant’s operations, many times they are not required for a facility to meet its effluent permit requirements. To Kara Buzanoski, DPW Director Mohamed Nabulsi, DPW Assistant Director Town of Nantucket, MA Page 1 CC File Subject Enhancements to the Surfside Wastewater Treatment Facility From Thomas E. Parece, P.E., Erik Meserve, P.E., Jarrod Trainor Date January 9, 2012 AECOM Enhancements to the Surfside WWTF Chelmsford, MA Nantucket, MA Page 2 of 23 These potential enhancements suggested by the Nantucket WWTF operating staff relate to the following processes and areas of the facility: • Influent Screening • Vacuum Truck Discharge Connection and Location • Miscellaneous Items This memorandum summarizes AECOM’s evaluation and recommendations for these potential improvements. AECOM Enhancements to the Surfside WWTF Chelmsford, MA Nantucket, MA Page 3 of 23 1. INFLUENT SCREENING The Surfside WWTF uses a GE/Zenon membrane bioreactor (MBR) system to produce high quality effluent. The lifespan and successful operation of MBRs is highly dependent on having a certain quality of wastewater in contact with the membrane surfaces. One item of concern can be so called “stringy” material being present in the wastewater and in contact with the membranes. Too much of this material can cause excessive fouling or breakage of the membranes. Currently, influent at the Surfside WWTF passes through an in-channel grinder in the Headworks, followed by a Parshall flume, an aerated grit chamber, primary clarifiers, pre-anoxic tanks and aeration tanks prior to the membrane bioreactors. In case of grinder failure, there is a bypass channel equipped with a manually cleaned bar rack. This design was reviewed, approved and accepted by GE/Zenon based on the fact that the facility has primary clarifiers and that the primary clarifiers will be operating and maintained in good operating condition. The primary clarifiers are intended to function to remove objectionable materials prior to the membranes. Many MBR facilities are not equipped with primary clarifiers and instead have a screening process. Currently a 10 year warranty for the membrane bioreactors which began upon facility startup is still in effect. Under the current operating conditions, the facility has continued to meet the requirements of its groundwater discharge permit. However, the operators at the Surfside WWTF have noted some buildup of stringy material such as hair, mop strings and rags on the membrane bioreactor cassettes. This buildup has caused some concern with the operating staff who requested a review of the influent screening options available to minimize the fouling of the membranes. The concern of the staff regarding fibrous material fouling the membrane bioreactors coupled with the recent failure of the in-channel grinder located at the Headworks has made replacement of the in-channel grinder a viable consideration. Replacing the grinder with a screening system is not required but could improve the removal of “stringy” material prior to the clarifiers. Modifications to the existing Headworks to include screening were considered as part of the upgrade project but were ruled out in an effort to minimize project costs. AECOM Enhancements to the Surfside WWTF Chelmsford, MA Nantucket, MA Page 4 of 23 A 2 mm screening technology would provide the amount of screening generally recommended by membrane manufacturers. Screen openings smaller than 2 mm generate too much head loss for use in this application and could remove excessive organic material necessary for downstream processes. The existing manual bar rack would be retained for operational flexibility. Note that the manufacturers of the screening options generally recommend a washer/compactor be paired with the screens. The washer/compactor processes the screenings after they have been removed from the flow stream in order to wash them of organic material, reduce the volume of the material to be handled and disposed of, and to reduce odor generation potential, all as needed to comply with local disposal laws. The following is a discussion of the various screening technology options. This discussion will first review the various types of screens and present uninstalled costs for each screening technology investigated. A discussion of possible methods of installation as well as conceptual drawings of the installations is presented thereafter, as different equipment may have different preferred locations for their successful operation and maintenance. Installed costs for each of these installation options are presented. 1.1 Band Screen A band screen has a rotating band of panels oriented parallel to the flow. Wastewater enters the screen and flows left or right through the rotating panels. Screenings are captured and lifted to the discharge level by the rotation of the band of panels. Solids are washed into a sluice by a spray wash system. Three manufacturers were contacted to obtain design requirements and preliminary pricing: JWC Environmental, Ovivo USA and Headworks. JWC Environmental The JWC Environmental band screen is intended to function as an in-channel unit and therefore it could be installed in the space vacated by the in channel grinder. Refer to Figure 1 which illustrates a typical band screen from JWC Environmental. Attachment A is a brochure of a band screen as manufactured by JWC Environmental. AECO Chelm OM msford, MA JW tha mg lea In en no Ov Ov off on In sc wa an AE we WC Environm at exists in th gd. However ave little room addition, AE nclosure for w ot required ah vivo USA vivo USA mar fer a screen nly sized for a addition, Ovi creening prior arrantee its 2 nd grit remova ECOM strong eather protect ental indicate he Surfside W r, based on t m for the wash ECOM strong weather protec ead of such a rkets band sc that would fit a maximum flo vo USA indic r to the fine s mm screens al. This limit gly recommen tion. Figure ed the band s WWTF Headw he layout of her/compacto gly recomme ction. JWC E a system. creens under t in the 3.5 fo ow of 3.5 mgd cated that this screen. Oviv s unless they ation impacts nds that the 1 - JWC Envir Enhan screen would works and pas the existing H or that is reco nds that the Environmental the Brackett oot wide Hea d and is insuff s system wou vo USA state were installe s the potentia equipment b ronmental Ba ncements to th fit in the 3.5 ss the Facility Headworks s ommended by equipment l stated that c Green brand adworks chan fficient for Sur uld require so ed that it wou ed after 6 mm al location for be installed in and Screen he Surfside W Nantucke Page 5 5 foot wide ch y’s peak flow tructure this w y the manufac be installed coarse screen name. While nnel, this scre rfside’s peak ome form of c uld be unwill m coarse scre r this band sc n an enclosu WWTF et, MA 5 of 23 hannel ws of 7 would cturer. in an ning is e they een is flows. coarse ing to eening creen. ure for AECOM Enhancements to the Surfside WWTF Chelmsford, MA Nantucket, MA Page 6 of 23 Headworks The Headworks Eliminator band screen is similar in operation to the JWC Environmental and Ovivo USA band screens. A unit sized to pass Surfside’s peak flows would not fit in the existing channel, as it requires eight feet of channel depth. The manufacturer indicated that coarse screening would not be required ahead of the screen based on a verbal description of the influent flow. Additionally, Headworks stated that the unit should not be installed in an outdoor location without weather protection. Based on the information received, the equipment produced by the three manufacturers are similar in operation but different in capabilities. Whereas JWC Environmental indicated that their band screen could fit in the existing channel, pass the peak flow and did not require coarse screening, Ovivo USA and Headworks indicated that a band screen with the desired characteristics was not available. The reason why manufacturers of similar equipment would have such significant differences in their installation recommendations is not clear. Table 1 summarizes the estimated uninstalled equipment costs for the three manufacturers. Table 1 - Band Screen Estimated Equipment Costs Manufacturer Item JWC Environmental Ovivo USA Headworks Band Screen $191,100 $230,000 $166,691 Washer/Grinder $65,500 $54,500 $66,099 Freight and Field Services $25,000 $25,000 $25,000 Total Uninstalled Cost $281,500 $309,500 $257,790 The installation of a band screen in the existing channel in place of the in-channel grinder would likely be limited to a single manufacturer due to the limitations discussed above. It is desirable that the design be structured such that multiple manufacturers could provide