HomeMy WebLinkAboutDPW Submission 2013_11_13_201404011027443515(508) 228-7244 (508) 228-7245 (508) 228-7289 FAX
DIVISIONS ENGINEERING HIGHWAY SEWER SANITATION FORESTRY MOSQUITO CEMETERY RECYCLING
188 madaket road
02554 Town of Nantucket
Massachusetts
Department of Public Works
PROJECT DESCRIPTION
SCONSET BLUFF STABILIZATION
November 13, 2013
The purpose of this Notice of Intent application is to request approval from the
Nantucket Conservation Commission for a coastal erosion control structure (CES) under
the Massachusetts Wetlands Protection Act and the local Nantucket Wetlands
Protection bylaw. The proposed work entails the installation of 4 geotextile tubes on
Siasconset Beach at the toe of the bluff adjacent to lots numbered 85 through 107A
Baxter Road. The tubes will be installed for a temporary period of time so as to allow
the Town of Nantucket sufficient time to address moving the Baxter Road public right of
way, the municipal water mains and services and the municipal sewer mains and
services. The application is made under the Limited Project provision of the State
Wetlands Protection regulations due to the requirement on the Town to maintain the
public rights of way and municipal utilities.
The application is made by the Town of Nantucket and the adjacent property
owners listed in the attached Appendix A.
The Town has been advised by Town Counsel that it is legally obligated to
provide access to the properties on the Baxter Road public right-of-way. During the
winter storms of 2013, significant retreat of the Sconset Bluff occurred, leaving the top
of the bank as close as 30 to 40 feet to the edge of Baxter Road in several areas and 60
to 70 feet in many others. While erosion rates can vary substantially from year to year,
another storm season similar to 2013 could render the road impassable and/or public
water supply breached, leaving the residences at the north end landlocked and the town
unable to provide fire protection and safe drinking water. If this were to occur the town
would not be able to provide emergency services to these properties.
The project is proposed to be constructed on the Siasconset Beach. It entails
four geotextile tubes stacked on top of each other with sand nourishment placed on top
and extra nourishment at the ends of the tubes. It will be maintained until Baxter Road
is relocated or the three year Conservation Commission Order of Conditions, and as
extended by the Conservation Commission, has expired, whichever time period is
shorter.
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SITE OVERVIEW AND EXISTING CONDITIONS
The project location is at the toe of the bluff at Sconset Beach. To the west is
bluff and, at the top of the bluff, Baxter Road. To the north is Sankaty Head Lighthouse
and to the south is residential property. A portion of the project is located on land
owned by the Town of Nantucket with the remaining project on privately owned land.
Only two properties, located in the middle of the project reach, include a residential
structure. Structures on other properties have either been relocated or lost to bluff
erosion.
Sconset bluff consists of dense sand that has proven to be highly erodible. The
upper layers of the bluff includes some silt material intermixed with the sand, while at
lower elevations (i.e., closer to the beach elevation) the material is a dense, poorly
graded sand. Wave action erodes the material at the toe of bluff, causing failure of the
bank, making toe protection the only viable option for stabilization of the roadway
above. Concurrent with this application, the town is working to relocate Baxter Road.
Four conceptual alternative plans have been developed that would extend Baxter Road
from Sankaty Lighthouse area west to Polpis Road. Each alternative results in impacts to
private properties and requires easements from property owners, which the town is in
the process of securing. It is expected that securing the necessary easements, defining
the road right-of-way, and completing the necessary design and construction would
take a minimum of three years and possibly much longer depending on the easement
negotiation process.
The Sconset Beach Preservation Fund, Inc. (SBPF) has made several other
stabilization project applications for the toe of the slope on Sconset Beach, with the
most recent application requesting authorization for hard armoring. There had been
some hope that construction of the SBPF project would occur in fall 2013, which would
mitigate the Town’s concerns regarding the roadway and utilities. However, in August it
became clear that the SBPF construction project would not occur this year. At that
point, the town’s Public Works Department began aggressively seeking methods to
protect those sections of Baxter Road that appear in imminent danger of failing during
this winter season.
PROPOSED ACTIVITIES
The application consists of placing approximately 1500 linear feet of geotubes
extending from 85 Baxter Road to 107a Baxter Road. While initial application materials
proposed two distinct sections of tubes only at the locations where roadway failure
appears imminent and where no structures currently exist, the issue of flanking could
not be resolved in the gap area between the two systems. Therefore, these application
materials request a continuous run of geotube from 85 Baxter Road to 107a Baxter
Road.
The proposed plan is a geotextile tube configuration that was developed in
coordination with geotextile tube manufacturer Maccaferri, Inc. (or an approved equal).
The MacTube® geotextile tube containers (geotubes) are made from a woven
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polypropylene (PP) geotextile. Manufactured in a sand color, the geotextile fabric is
woven in a rip-resistant weave pattern for maximum resistance to mechanical damage.
The system will consist of four tubes, each with a 45-foot circumference (approximately
19 feet wide and 6.5 feet tall). The tubes will be 100 or 200 feet long through the
project area, with returns set at a 45-degree angle constructed with 50-foot long tubes.
Following construction of the tubes (see below for construction methodology) sand
cover will be provided and nourishment will be performed to protect the tubes and
mitigate for loss of the bank as a sediment source. Aside from the design to provide
adequate nourishment sand, maintaining cover over the tubes is critical to maintaining
their life expectancy since the geotextile is prone to degradation from ultraviolet light.
Sand fill will be secured from on-island sources of compatible sand.
The embankment above the toe shows evidence of rill erosion from rainfall and
runoff from the grass areas along the top. The town is working with the property
owners to reduce runoff that discharges over the top of the slope, and will provide a low
berm along the easterly side of the roadway to direct water toward Baxter Road. This
will only be completed in areas where the roadway contributes to flow of water over
the bluff. In addition to redirecting runoff, jute netting will be placed on the bank face
to protect the exposed soil. Netting will be placed this fall immediately upon receipt of
approval to proceed. In the spring, native plantings (e.g., beach grass and woodier
species) will be added to the slope to further reduce erosion.
WETLANDS RESOURCE AREAS
The proposed project is located on the coastal beach below the coastal bank. All
work associated with the proposed project will be in the following resource areas which
are subject to the jurisdiction of the Nantucket Conservation Commission under the
State Wetlands Protection Act and the Nantucket Wetlands Protection Bylaw and
Regulations:
-Coastal Beach
-Coastal Bank
-Land Subject to Coastal Storm Flowage
COMPLIANCE WITH STATE AND LOCAL PERFORMANCE STANDARDS
The installation of the proposed coastal erosion structure (CES) will occur on the
beach resource area adjacent to the coastal bank resource area for the purpose of
temporarily stabilizing the coastal bank adjacent to Baxter Road so that the Town can
relocate Baxter Road and utilities. This proposed project is filed under the below cited
section of the State Wetlands Protection Act: “(7) 310 CMR 10.24 is not intended to prohibit the issuing authority from imposing such additional conditions as are necessary to contribute to the interests of M.G.L. c. 131, § 40
where the indicated minimizing measures are not sufficient.
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(c) Notwithstanding the provisions of 310 CMR 10.25 through 10.35, the issuing
authority may issue an Order of Conditions and impose such conditions as will contribute
to the interests identified in M.G.L. c. 131, § 40 permitting the following limited project (although no such project may be permitted which will have any adverse effect on specified habitat sites of rare vertebrate or invertebrate species, as indentified by
procedures established under 310 CMR 10.37):
1. Maintenance and improvement of existing public roadways”
Town Counsel has authored a memo which is attached as Appendix B that addresses
this issue.
STATE WETLANDS REGULATION PERFORMANCE STANDARDS
Notations by the applicant regarding compliance with the performance standards are in
italics below:
310 CMR 10.27 COASTAL BEACHES “WHEN A COASTAL BEACH IS DETERMINED TO BE SIGNIFICANT TO STORM
DAMAGE PREVENTION, FLOOD CONTROL, OR PROTECTION OF WILDLIFE
HABITAT, 310 CMR 10.27(3) through (7) SHALL APPLY” “(3) Any project on a coastal beach, except any project permitted under 310 CMR
10.30(3)(a), shall not have an adverse effect by increasing erosion, decreasing the volume
or changing the form of any such coastal beach or an adjacent or downdrift coastal beach.”
The proposed improvements will increase bank stability and mitigation will insure that
the proposed CES will not adversely impact the volume of sand generated by this area of
beach. The proposed sand mitigation and nourishment are intended to prevent adverse
effects on the ability of the bank to serve as a sediment source.
“(4) Any groin, jetty, solid pier, or other such solid fill structure which will interfere with littoral drift, in addition to complying with 310 CMR 10.27(3), shall be constructed as
follows:
(a) It shall be the minimum length and height demonstrated to be necessary to maintain
beach form and volume. In evaluating necessity, coastal engineering, physical oceanographic and/or coastal geologic information shall be considered.
The engineers have designed the proposed improvements to be sized to the minimum
length and height possible to stabilize Baxter Road.
(b) Immediately after construction any groin shall be filled to entrapment capacity in
height and length with sediment of grain size compatible with that of the adjacent beach.
No groin is proposed by this project.
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(c) Jetties trapping littoral drift material shall contain a sand by-pass system to transfer
sediments to the downdrift side of the inlet or shall be periodically redredged to provide beach nourishment to ensure that downdrift or adjacent beaches are not starved of sediments.”
No jetty is proposed by this project. “(5) Notwithstanding 310 CMR 10.27(3), beach nourishment with clean sediment of a
grain size compatible with that on the existing beach may be permitted.”
Sand is to be used for beach nourishment as noted in this performance standard. Sand
that is compatible with this performance standard will be used. This is supported in our
application materials.
“(6) In addition to complying with the requirements of 310 CMR 10.27 (3) and 10.27(4),
a project on a tidal flat shall if water-dependent be designed and constructed, using best
available measures, so as to minimize adverse effects, and if non-water-dependent, have
no adverse effects, on marine fisheries and wildlife habitat caused by: (a) alterations in water circulation, (b) alterations in the distribution of sediment grain size, and
(c) changes in water quality, including, but not limited to, other than natural fluctuations
in the levels of dissolved oxygen, temperature or turbidity, or the addition of pollutants.”
This project does not propose any work in a tidal flat.
“(7) Notwithstanding the provisions of 310 CMR 10.27(3) through 10.27(6), no project
may be permitted which will have any adverse effect on specified habitat sites or rare vertebrate or invertebrate species, as identified by procedures established under 310 CMR 10.37.”
This project will not have an adverse effect on specified habitat as there are no sites
adjacent to or within the project area.
310 CMR 10.30 COASTAL BANKS “WHEN A COASTAL BANK IS DETERMINED TO BE SIGNIFICANT TO STORM
DAMAGE PREVENTION OR FLOOD CONTROL BECAUSE IT SUPPLIES
SEDIMENT TO COASTAL BEACHES, COASTAL DUNES OR BARRIER BEACHES, 310 CMR
10.30(3)
through (5) SHALL APPLY:”
“(3) No new bulkhead, revetment, seawall, groin or other coastal engineering structure
shall be permitted on such a coastal bank except that such a coastal engineering structure shall be permitted when required to prevent storm damage to buildings constructed prior
to the effective date of 310 CMR 10.21 through 10.37 or constructed pursuant to a Notice
of Intent filed prior to the effective date of 310 CMR 10.21 through 10.37 (August 10,
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1978), including reconstructions of such buildings subsequent to the effective date of 310
CMR 10.21 through 10.37, provided that the following requirements are met:
(a) a coastal engineering structure or a modification thereto shall be designed and constructed so as to minimize, using best available measures, adverse effects on adjacent or nearby coastal beaches due to changes in wave action, and
(b) the applicant demonstrates that no method of protecting the building other than the
proposed coastal engineering structure is feasible.
(c) protective planting designed to reduce erosion may be permitted.”
This standard states that new coastal structures are not permitted except when the
structure is required to prevent storm damage to buildings construction prior to 1978.
Baxter Road and the water main located on the eastern edge of the pavement were
constructed prior to 1978. Without the proposed coastal structure Baxter Road will be
lost and storm damage will occur. Since Baxter Road is not a building, the project does
not meet this standard and waiver is required. The application materials provided with
the NOI clearly outline why no alternatives to the proposed plan exist. Alternatives were
evaluated that considered stabilizing the roadway from the top of the bluff rather than
the bottom. Input and recommendations from the project geotechnical engineer clearly
advised against such measures, leaving no alternatives but toe stabilization. The town is
in the process of relocating Baxter Road, but this process is expected to take a number of
years to implement.
The coastal engineering structure has been designed to minimize to the extent possible,
adverse effects to adjacent beaches on adjacent beaches. These impacts are mitigated
through the placement of sand nourishment. Protective plantings are proposed but
cannot be installed until spring 2014. These are proposed to reduce rill erosion from the
upper bank area.
“(4) Any project on a coastal bank or within 100 feet landward of the top of a coastal
bank, other than a structure permitted by 310 CMR 10.30(3), shall not have an adverse effect due to wave action on the movement of sediment from the coastal bank to coastal beaches or land subject to tidal action.”
The project will not reduce the ability of the land to absorb and contain floodwaters or
buffer inland areas from wave damage. In fact, the project is intended to prevent wave
damage from occurring. The sand mitigation proposed is intended to absorb wave
action, mimicking the natural bank condition. “(5) The Order of Conditions and the Certificate of Compliance for any new building
within 100 feet landward of the top of a coastal bank permitted by the issuing authority
under M.G.L. c. 131, § 40 shall contain the specific condition: 310 CMR 10.30(3),
promulgated under M.G.L. c. 131, § 40, requires that no coastal engineering structure, such as a bulkhead, revetment, or seawall shall be permitted on an eroding bank at any time in the future to protect the project allowed by this Order of Conditions.”
The project does not propose structures at the top of the coastal bank.
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LOCAL WETLANDS BYLAW PERFORMANCE STANDARDS
2.01 LAND UNDER THE OCEAN “Land Under the Ocean shall be presumed significant to an Interest protected by the
Bylaw as referenced in Section A, therefore the following regulations apply:”
1. “Dredging shall be designed and carried out using the best available measures as
determined by the Commission so as to have the least possible adverse effects or changes in marine productivity caused by changes in, or resulting from suspension or transport of pollutants, sediment transport, smothering of bottom organisms, accumulation of
pollutants by organisms, destruction of habitat or nutrient source areas, or changes in
water circulation and water quality.”
This project does not propose any dredging.
2. “All dredging shall use best available measures to minimize adverse effects caused
by changes in bottom topography resulting in an increase in height and velocity of waves
hitting the shore, localized changes in circulation patterns or in changes in sediment transport which affect natural replenishment of beaches or maintenance of channels.”
This project does not propose any dredging.
3. “Residential piers shall be constructed so as not to change shoreline movement of
sediment, harm shellfish resources, obstruct commercial shellfishing, or obstruct the reserved public rights of fishing, fowling, navigation, or passage. Residential piers shall
not displace public moorings without written approval from the Harbormaster. No solid
fill piers shall be permitted.”
This project does not propose any piers.
4. “Construction of commercial piers shall be in compliance with the Town of
Nantucket Zoning Bylaws and shall not affect sediment transport, and shall not destroy or
pollute fisheries and shellfish habitat or nutrient source areas for those resources. No
solid fill piers shall be permitted.”
This project does not propose any piers.
5. “Best available measures as determined by the Commission shall be used to
minimize adverse effects of a commercial or residential pier on the interests protected by the Bylaw.”
This project does not propose any piers.
6. “Aquaculture projects shall be undertaken pursuant to such means as may be established by the Commission so as to have the least possible adverse effect on wildlife, erosion control, storm damage prevention, flood control, recreation or public access. No
destruction of habitat or areas where shellfish feed, or change in water quality or
circulation in any manner which adversely affects productivity of marine fisheries or
shellfish beds shall be permitted.”
This project does not propose any aquaculture component. This project will not have an
adverse effect on habitat, fisheries or shellfish beds.
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7. “No new bulkheads or coastal engineering structures shall be permitted to protect
structures constructed or substantially improved after 8/78. Bulkheads may be rebuilt
only if the Commission determines there is no environmentally better way to control an erosion problem, including in appropriate cases the moving of the threatened building. Other coastal engineering structures may be permitted only upon a clear showing that no
other alternative exists to protect a structure built prior to 9/78, but not substantially
improved, from imminent danger.”
There is no other alternative for erosion control at this location other than the
installation of a coastal erosion control structure.
8. “Water dependant projects shall be designed and performed so as to cause no
adverse effects on wildlife, erosion control, marine fisheries, shellfish beds, storm
damage prevention, flood control, recreation, and aquatic vegetation.”
Coastal erosion control structures are considered to be water dependent, however; no
adverse effects are anticipated to land under the ocean as a result of the construction or
removal of this temporary CES. This is supported by the fact that no work is proposed
directly within the ocean with the possible exception of water withdrawal for creating
the slurry that fills the tubes.
Coastal Beaches
“2.02 COASTAL BEACHES (and TIDAL FLATS)
“A Coastal Beach, Tidal Flat or Land within 100 feet of a Coastal Beach or Tidal Flat
shall be presumed significant to the Interests Protected by the Bylaw, as referenced in
Section A, therefore the following regulations shall apply.“ 1. “The provisions of Section 2.01B (1-8) (Land Under the Ocean) shall apply to coastal beaches and tidal flats.”
Please see narrative above for Land under the Ocean. There are no Tidal Flats in the
project area.
2. “No new bulkheads or coastal engineering structures shall be permitted to protect
structures constructed, or substantially improved, after 8/78. Bulkheads may be rebuilt
only if the Commission determines there is no environmentally better way to control an
erosion problem, including in appropriate cases the moving of the threatened building.
Other coastal engineering structures may be permitted only upon a clear showing that no other alternative exists to protect a structure built prior to 9/78, and not substantially
improved, from imminent danger.”
There is no other alternative for erosion control at this location other than the
installation of a coastal erosion control structure.
3. Dredging projects in flats must be done in accordance with such procedures as the
Commission determines would disturb the absolute minimum amount of habitat possible
for both the borrow site and the area in which spoils are placed.
This project does not propose any dredging.
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4. “Clean fill of compatible grain size may be used on a Coastal Beach but not on a
Tidal Flat, only if the Commission authorizes its use, and only if such fill is to be used for a beach or dune nourishment project. All possible mitigation measures shall be taken, as determined by the Commission, to limit the adverse effects of the fill.”
Sand is to be used for beach nourishment as noted in this performance standard. Sand
that is compatible with this performance standard will be used. This is supported in our
application materials, which clearly outline the alternatives evaluated for stabilizing
Baxter Road and the conclusion that the only viable alternative, based on available
engineering and geotechnical data, is stabilization of the toe of the bluff.
5. No part of any septic system shall be placed in shifting sands or on a coastal beach.
The septic leach facility shall be at least 100 feet from the spring high tide line.
This project does not propose any septic system. 6. “All work on projects which are not water dependent shall maintain at least a 25-
foot natural undisturbed area adjacent to a coastal beach. All structures which are not
water dependent shall be at least 50 feet from a coastal beach.”
Coastal erosion control structures are considered to be water dependent.
7. “In areas of eroding shoreline, the distance from all buildings to the coastal beach
shall be at least 20 times the average annual shoreline erosion or 100 feet, whichever is the lesser. The average annual shoreline erosion rate shall be determined by averaging
the annual erosion rate over a 150 year period ending the date the NNOI was filed, or if
no NNOI was filed, the date construction began. If erosion data is not available for the
150-year period, the Commission shall determine the average annual erosion rate from
such lesser time period for which erosion data is available. In cases where documentation can be provided to show that the use of the 150-year period is
inappropriate to existing shoreline characteristics and trends, alternate shoreline change
rates may be used when based on a preponderance of credible evidence.”
This project does not propose any buildings.
8. “Vehicular access for existing houses or for recreational use shall be as unpaved ways
and shall be done in accordance with such procedures as the Commission determines will
minimize any adverse effect on the beach and the Interests of the Bylaw.”
This project does not propose any vehicular access to residential properties.
9. “Fertilizers shall be used in accordance with the “Best Management Practices for
Landscape Fertilizer Use on Nantucket Island”
This project does not propose the use of any fertilizers.
10. “The Commission may impose such additional requirements as are necessary to
protect the Interests Protected by the Bylaw.”
The Applicants acknowledge the right of the Commission to apply additional
requirements to protect the Interests of the Bylaw.
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“2.05 COASTAL BANKS
“Coastal Banks or Land within 100 feet of a Coastal Bank shall be presumed significant to the Interests Protected by the Bylaw as referenced in Section A, therefore the following regulations shall apply.”
1. “No new bulkheads, coastal revetments, groins, or other coastal engineering
structures shall be permitted to protect structures constructed, or substantially improved,
after 8/78 except for public infrastructures. Bulkheads and groins may be rebuilt only if the Commission determines there is no environmentally better way to control an erosion problem, including in appropriate cases the moving of the threatened buildings and/or
public infrastructure. Other coastal engineering structures may be permitted only upon a
clear showing that no other alternative exists to protect a structure that has not been
substantially improved or public infrastructure built prior to 9/78, from imminent danger.”
Baxter Road and the water main located on the eastern edge of the pavement were
constructed prior to 1978. The application materials provided with the NOI clearly
outline why no alternatives to the proposed plan exist. Alternatives were evaluated that
considered stabilizing the roadway from the top of the bluff rather than the bottom.
Input and recommendations from the project geotechnical engineer clearly advised
against such measures, leaving no alternatives but toe stabilization. The town is in the
process of relocating Baxter Road, but this process is expected to take a number of years
to implement.
2. “Piers shall be constructed in compliance with the Town of Nantucket Zoning
Bylaws using procedures determined by the Commission to be the best available measures to minimize adverse effects on Interests Protected by the Bylaw.”
This project does not propose any piers.
3. “All projects shall be restricted to activity as determined by the Commission to have no adverse effect on bank height, bank stability, wildlife habitat, vegetation, wetland
scenic view, or the use of a bank as a sediment source.”
The proposed improvements will increase bank stability and will not adversely impact
habitat, vegetation or scenic view. The proposed sand mitigation and nourishment is
intended to prevent adverse effects on the ability of the bank to serve as a sediment
source.
A Waiver under Section 1.03F number 3a is requested to the Nantucket Wetlands Bylaw
from the performance standard for Coastal Bank #3 “use of the bank as a sediment
source.
4. “Elevated walkways designed not to affect bank vegetation shall be required for
pedestrian passage over a bank.”
This project does not propose any elevated walkways.
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5. “All projects which are not water dependent shall maintain at least a 25-foot natural
undisturbed area adjacent to a coastal bank. All structures which are not water dependant shall be at least 50 feet from a coastal bank.”
Coastal erosion control structures are considered to be water dependent.
6. “The septic leach facility of a septic system shall be constructed at least 100 feet
from the top of the coastal bank and shall not be located within the face of the coastal
bank.“
This project does not propose any septic leaching facility.
7. “In areas of an eroding coastal bank, the distance from all new structures to the
coastal bank shall be at least 20 times the average annual erosion rate or 100 feet,
whichever is the lesser. The average annual erosion rate shall be determined by averaging the annual erosion over a 150-year period ending with the date the NOI was
filed, or if no NOI was filed, the date construction began. If erosion data is not available
for the 150-year period, the Commission shall determine the average annual erosion rate
from such lesser time for which erosion data is available. In cases where documentation
can be provided to show that the use of the 150-year period is inappropriate to existing coastal shoreline characteristics and trends, alternate shoreline change rates may be used
with the approval of the Commission.”
The project does not propose structures at the top of the coastal bank.
8. “All permits issued for the substantial improvement of an existing building or new
construction of buildings under the Bylaw within 100 feet landward of the top of a
coastal bank shall contain the specific condition that no coastal engineering structure of any kind shall be permitted on an eroding bank in the future to protect the project allowed by this permit, except those coastal engineering structures allowed by a waiver issued
pursuant to Section 1.03F of these regulations.”
This project does not propose any building structure.
9. “The Commission may impose such additional requirements as are necessary to
protect the Interests Protected by the Bylaw.”
The Applicants acknowledge the right of the Commission to apply additional
requirements to protect the Interests of the Bylaw.
“2.10 LAND SUBJECT TO COASTAL STORM FLOWAGE
Land Subject to Coastal Storm Flowage or Land within 100 feet of Land Subject to
Coastal Storm Flowage shall be presumed significant to the Interests Protected by the
Bylaw as referenced in Section A, therefore the following regulations shall apply:
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1. “The work shall not reduce the ability of the land to absorb and contain flood
waters, or to buffer inland areas from flooding and wave damage.”
The project will not reduce the ability of the land to absorb and contain floodwaters or
buffer inland areas from wave damage. In fact, the project is intended to prevent wave
damage from occurring. The sand mitigation proposed is intended to absorb wave
action, mimicking the natural bank condition.
2. “Building upon areas subject to coastal storm flowage in locations where such structure would be subject to storm damage may not be permitted. If permitted, all construction must be in compliance with state and local building code regulations for
flood hazard areas.”
Baxter Road falls within the definition in the local bylaw for a “structure”:
“Structure - a combination of materials assembled at a fixed location to give support or
shelter such as a building, framework, retaining wall, platform, bin, radio antenna mast,
or the like. The term structure may also be applied to appurtenances that are
constructed of impervious surfaces, such as but not limited to swimming pools,
recreational playing courts, roads”
No structures are proposed that would be regulated by state or local building codes.
3. “All private underground fuel tanks shall be outside the 100-year floodplain.
Commercial tanks shall be outside the 100-year floodplain, or if the Commission determines this is not practicable, the commercial tanks shall be secured so that they
cannot float loose.”
No fuel tanks are proposed.
4. “Building upon areas subject to coastal storm flowage in locations where such
structure would be subject to storm damage may not be permitted. If permitted, all
construction must be in compliance with state and local building code regulations for flood hazard areas.”
No structures are proposed that would be regulated by state or local building codes.
5. “Fertilizers shall be used in accordance with the “Best Management Practices for Landscape Fertilizer Use on Nantucket Island”
No fertilizers are proposed to be used.
6. “The Commission may impose such additional requirements as are necessary to
protect the Interests Protected By the Bylaw.”
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The Applicants acknowledge the right of the Commission to apply additional
requirements to protect the Interests of the Bylaw.
In summary, this proposed project has been designed to be a temporary measure to
stabilize the bluff below Baxter Road while the Town takes the necessary time to move
the roadway pavement and the public utilities in the roadway, which includes municipal
water and municipal sewer. The proposed coastal erosion control structure (CES) will be installed at the toe of the coastal bank on the coastal beach which is land subject to
coastal storm flowage.
All applicable performance standards are met except the performance
standard for Coastal Bank (#3) “…use of the bank as a sediment source.” Due to
this, a waiver is requested under Section 1.03F number 3a: “The Commission may grant a waiver from these regulations when the Commission finds that, given existing conditions, the proposed project will not adversely impact the interests
identified in the Bylaw and there are no reasonable conditions or alternatives that
would allow that project to proceed in compliance with the regulations.”
The project has been proposed so as not to create an adverse effect on the site. Nourishment mitigation of 20 cubic feet per linear foot has been proposed so as to insure
that the littoral system has an adequate source of sediment. This amount has been chosen
because it exceeds the calculated amount that could be expected from this section of
beach without the CES installed.
The geotube alternative has been chosen because of its hardiness. Lesser alternatives have been dismissed because they cannot be depended on for consistent stabilization of
the slope in a series of storms. The jute or coir logs are not able to withstand forceful
storms, especially in series. When breached they require complete reinstallation. Strictly
sand nourishment has not been proposed due to concerns expressed in previous
applications regarding protection of the ocean cobble habitat. The town is not prepared or able to maintain these lesser alternatives at all times. The hardiest installation that the
Town feels could be allowed by the Conservation Commission is what has been
proposed. Rock stabilization has not been proposed because that has not been permitted
to date. The Town feels that this geotube alternative is the best option to temporarily stabilize the Baxter Road bluff during the time it needs to move the roadway and
municipal utilities.
(508) 228-7244 (508) 228-7245 (508) 228-7289 FAX
DIVISIONS ENGINEERING HIGHWAY SEWER SANITATION FORESTRY MOSQUITO CEMETERY RECYCLING
APPENDIX A Property owners list
(508) 228-7244 (508) 228-7245 (508) 228-7289 FAX
DIVISIONS ENGINEERING HIGHWAY SEWER SANITATION FORESTRY MOSQUITO CEMETERY RECYCLING
APPENDIX B
Town Counsel memo