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Home My WebLink About47 SE48_3115 SBPF Sconset Expanded Project recap 03_11_2019Notice of Intent Expanded Baxter Road and Sconset Bluff Storm Damage Prevention Project March 11, 2019 Sept 2018 Existing Project Jute/Coir Envelopes NOI Summary 4 geotextile tube tiers to provide continuous protection from 59 to 119 Baxter Road ▪North from Existing Project to 119 Baxter Road = 895 ft ▪South from Existing Project to 59 Baxter Road (plus returns) = 1,978 ft ▪Length of Proposed Extension = 2,873 feet ▪Extension of Existing Project 2 Existing Project Proposed Project Project Purpose and Need 3 Source: Correspondence from G. Berman to J. Carlson, 01 February 2019 4 Northern Cross-Sections Summary of Closing Topics 5 ▪Eligibility for a CES ▪Maintaining a Walkable Beach ▪Effects on Abutting Beach ▪Effects on Nearby Beaches ▪Proposed Mitigation ▪Comparison of Existing (Approved) Project and Proposed Extension Project ▪Compliance with Performance Standards Homes in Question 6 Review of Building Department materials submitted by Commissioner Golding identified four home that we disagree on eligibility ▪83 Baxter Road ▪79 Baxter Road ▪77 Baxter Road ▪73 Baxter Road 83 Baxter Road 7 2001:Relocate one story 2,330 s.f.dwelling and place on a newfoundationonthesamelot.No dimensional changes occurred:0%change in habitable space. 1991:Addition to a one story 2,140 s.f.dwelling,Building Permit issuedfora200s.f.sunroom addition and replacement roof over diningroom:9.3%increase in floor area. 1982:Addition to a one story 2,041 s.f.dwelling.Building Permit issuedfora99s.f.kitchen extension:4.9%increase in floor area. Structure dimension was determined to be 2,041 s.f.based onreviewofplotplansincludedinthe2001,1982 and 1991 BuildingPermitfiles. Summary:Cumulative increase in habitable space from 1982 to 1991 was 299 s.f.divided by original floor area of 2,041 s.f.correlates to 14.2% increase in floor area, assumed to be habitable space. 83 Baxter Road 8 May 11, 1981 83 Baxter Road 9 April 10, 1993 83 Baxter Road 10 2001 House Move 79 Baxter Road 11 2013:Relocate single family house on the same lot.Building Permitreportsdwellingcontains3,738 s.f.total floor area.No dimensionalchangeswithbuildingrelocation:0%change in habitable area. 1999:Replace windows and redo roof walk.No dimensional changes:0%change in habitable area. 1997:Deck addition to dwelling.Building Permit issued for a 287 s.f.deckaddition:0%in habitable area 1989:Alteration and addition to single family 3,272 s.f.dwelling.BuildingPermitissuedfor466s.f.net addition,use undefined:14.2%increase in floor area. Pre-addition total floor area was determined to be 3,272 s.f.as therearenootheradditionsrecordedinBuildingDepartmentfilesbetween1989and2013. Summary:Cumulative increase in habitable space from 1989 to 2013 was466s.f.divided by original floor area of 3,272 s.f.correlates to14.2%increase in floor area,assumed to be habitable space.Therefore,this dwelling is eligible as a pre-1978 house becausethecumulativeincreaseinhabitablespaceislessthan20%. 77 Baxter Road 12 2006:Demolish 558 s.f.bunk house:558 s.f.reduction in habitable space. 2005:Relocate single family house on same lot and add 555 s.f.additionperCertificateofAppropriatenessNo.47427:555 s.f increaseinhabitablespace. Summary:Net change is a 3 s.f.reduction in floor area.Therefore,thisdwellingiseligibleasapre-1978 house because the cumulativeincreaseinhabitablespaceislessthan20%. 2012:Relocate single family dwelling on same lot.Demolish 350 sf of 1st floor,add 150 sf to first floor for kitchen,renovate baths,reside,and re-roof.Net change is a 200 s.f.reduction in floor area. 1989:Construct a 10 ft x 14 ft (140 s.f.)addition to garage for storage:0%increase in habitable space. 1989:Construct 253 s.f.addition for library. 1986:Addition of 2nd story bathroom no area provided.Bathroom is notconsideredhabitablespace–0%increase in habitable space. Summary:No total square foot of floor area could be affirmed from therecords.Review of the 1989 permit application suggests theprinciplestructurehadafloorareaof1,534 s.f.Records show thatbetween1989and2013therewasanetincrease53sfinhabitablespace.This correlates to approximately a 3.5%increaseinfloorarea. 73 Baxter Road Walkable Beach In Front of Existing Array 13 Walkable Beach In Front of Existing Array 14 Walkable Beach In Front of Existing Array 15 Existing Array Not Damaging Adjacent Beaches 16 Profile Starting Date & Position (feet)(1) Ending Date & Position (feet)Total Change (feet)Annualize Rate of Change (feet / year) 92.1 10/2014 / -1.7 9/2018 / +5 6.7 ft Accretion 1.68 ft /yr Accretion 92(2)10/2014 / -55.7 9/2018 / -61.3 5.6 ft Retreat 1.4 ft /yr Retreat Existing Geotube Systemt 90.85 10/2014 / -2.1 9/2018 / +4.9 7.0 ft Accretion 1.75 ft / yr Accretion 90.8 10/2014 / -1.3 9/2018 / +7.3 8.6 ft Accretion 2.15 ft/yr Accretion Table 2.Review of Shoreline Change Adjacent to the Existing GeotubeSystem (1)Position is feet from a previously established baseline point.(2)Approximate location of the clay head At Profile 92 there was about a 10-foot retreat documented from October2014toOctober2015.Since October 2015 the shoreline has beenrelativelystabileatProfile92,with 4.4 feet of accretion observed fromOctober2105toOctober2018,and that correlates to an annualizedaccretionrateof1.47 feet per year. Existing Array Not Damaging Nearby Beaches 17 Existing Array Not Damaging Nearby Beaches 18 Sand Mitigation Summary Protocol Summary: Complete construction placing 22 cy/lf of compatible sand on the template. Periodically contribute sand to the littoral drift system by covering exposed tubes after erosion events. “What was Contributed from the Template?”Determine volume of sand contributed to the littoral drift system during the winter storm season. Replace sand on the template with the volume of sand contributed to the littoral drift system the previous year or up to 22 cy/lf, whichever is greater, to “top it off.” In response to peer review comment SBPF proposes to place a minimum of 8.8 cy/lf of sand –length weighted average annual Coastal Bank contribution –or volume of sand contributed off the template, whichever is greater. 19 Comparison of Existing Project to Extension Project (Minor Changes based on “Lessons Learned”) 20 PROJECTELEMENT EXISTING PROJECT EXPANDED PROJECT Project Purpose : +/-950 feet Protects 2 homes and public infrastructure and 5 vacant lots (to protect public infrastructure or “gap lots” per the state definition). +/-2,900 feet Protects 21 lots -16 homes and 5 vacant lots (to protect public infrastructure or “gap lots” per the state definition). Comparison of Existing Project to Extension Project (continued) 21 PROJECT ELEMENT EXISTING PROJECT EXPANDED PROJECT Geotube System Design: Geotube Layout Four tier geotube configuration covered by sand template. Same design. Difference is lowest geotube set at elevation -3 feet MLW instead of 0 feet MLW Geotube Returns Sloped returns that tie into adjacent Coastal Bank at a shallow angle. Same design. Return Extensions None originally –Coir rolls approved November 28, 2018. Add Special Condition to install coir roll return extensions when appropriate. Comparison of Existing Project to Extension Project (continued) 22 PROJECT ELEMENT EXISTING PROJECT EXPANDED PROJECT Sand Template Management Place sand on template at a rate of 22 cy/lf/yr and use that sand stockpile to recover exposed tubes after erosion events. Import sand during storm season as needed to replenish stockpile. Fill template to 22 cy/lf before each storm season and use that sand stockpile to recover exposed tubes after erosion events. Import sand during storm season as needed to replenish stockpile. Minimum volume of 8.8 cy/lf (average annual volume off Coastal Bank) or volume to re- establish 22 cy/l, whichever is greater Comparison of Existing Project to Extension Project (continued) 23 PROJECT ELEMENT EXISTING PROJECT EXPANDED PROJECT Monitoring: Extensive monitoring program: ▪Shoreline change quarterly; ▪Bathymetric Survey semi- annually; ▪Underwater video semi- annually; ▪Post-storm inspections; ▪Template survey annually. Extensive program with minor modifications2: ▪Shoreline change semi- annually; ▪Bathymetric Survey annually; ▪Underwater video once every 3 year; ▪Post storm inspections; ▪Template survey annually; ▪Discontinue reporting on Alternative Access Agreement Comparison of Existing Project to Extension Project (continued) 24 PROJECT ELEMENT EXISTING PROJECT EXPANDED PROJECT Reporting:Annual Report and interim reports to the Commission Same 25 Notes: 1.Per the Nantucket Bylaw 14 homes are eligible as pre-1978 structures,2 are non- eligible structures but can be protected as “gap lots”,and 5 are vacant lots eligible for protection to protect public infrastructure from damage. 2.Correspondence from Greg Berman,Woods Hole Sea Grant |Cape Cod Cooperative Extension to Jeff Carlson (Natural Resources Coordinator,Town of Nantucket) dated April 7,2017 Regarding the Independent Review of the 2016 Annual Report, noted the following: ▪Shoreline Monitoring –The requested reduction to 2 profiles per year is reasonable based on the collected data so far as well as more consistent with MassDEP guidance.(pg.4) ▪Wetland Well Monitoring –If the data from 2001-2007 shows similar dry levels as this project the well monitoring could be discontinued.(pg.5) ▪Beach Invertebrate Monitoring –The invertebrate monitoring could be discontinued as no impacts to the few species have been observed.(pg.5) ▪Underwater Video Monitoring –Video monitoring likely is not needed yearly. (pg.6) Comparison of Existing Project to Extension Project (continued) Expanded Project Compliance to Performance Standards Detailed review of compliance with the Regulations and Performance standards was presented on October 1, 2018 Public Hearing Comparing the Existing Project to the Expanded Project we observe: 1.Expanded Project is very similar in design with the Existing Project, with minor changes based on “Lessons Learned;” 2.A robust sand mitigation is proposed for the Expanded Project, as was provided for the Existing Project; and 3.Shoreline monitoring to date has not documented damage to nearby Coastal Beaches Therefore the Expanded Project meets the requirements of the Act and Bylaw just as the Existing Project does. 26 27 Thank You