HomeMy WebLinkAboutBoard of Selectmen Agenda March 9, 2011 Packet_201402061634247703Town of NantucketTown of Nantucket Water Quality Strategic PlanWater Quality Strategic PlanProgress UpdateProgress UpdatePresented to the Board of SelectmenPresented to the Board of Selectmen3/9/20113/9/2011
VisionVision•• To preserve or improve water quality To preserve or improve water quality within and surrounding Nantucket within and surrounding Nantucket Island.Island.
MissionMission•• ““To maintain, improve or protect water quality To maintain, improve or protect water quality levels within all harbors, levels within all harbors, embaymentsembayments, estuaries, , estuaries, wetlands, ponds and beaches within and wetlands, ponds and beaches within and surrounding the island of Nantucket in surrounding the island of Nantucket in accordance with local and state standards and to accordance with local and state standards and to safeguard all Nantucket municipal and private safeguard all Nantucket municipal and private sources of potable water; and, to regularly sources of potable water; and, to regularly inform Nantucketinform Nantucket’’s citizens about the Towns citizens about the Town’’s s water quality measurement efforts and results.water quality measurement efforts and results.””
Example of StandardsExample of Standards•• As adopted by the Nantucket and Madaket Harbors Action PlanAs adopted by the Nantucket and Madaket Harbors Action PlanThe Massachusetts Water Quality Standards for SA-Classified WatersParameterStandardDissolved OxygenNot less than 6.0 mg/L unless background conditions are lower; natural seasonal and daily variations above this level shall be maintained; levels shall not be lowered below 75% of saturation due to a discharge.TemperatureShall not exceed 85°F nor a maximum daily mean of 80°FpHShall be in the range of 6.5 through 8.5 standard units and not more than 0.2 units outside the normally occurring range.Fecal Coliforma.Waters approved for shellfishing shall not exceed a geometric mean (Most Probable Number or MPN) of 14 colonies/100mL, nor shall more than 10% of the samples exceed an MPN of 43 colonies/100 mLb.Waters not designated for shellfishing shall not exceed a geometric mean MPN of 200 colonies/100mL, nor shall more than 10% of the samples exceed an MPN of 400 colonies/100 mLSolidsShall be free from floating, suspended, and settleable solids in concentrations of combinations that would impair any use assigned to this class, that would cause any objectionable conditions or that impair the benthic biota or degrade the chemical composition of the bottom.Color and TurbidityShall be free from color or turbidity in concentrations or combinations that are aesthetically objectionable or would impair any use assigned to this class.Oil and GreaseShall be free from oil and grease and petrochemicals.Taste and OdorNone other than that of natural origin.
Example of StandardsExample of Standards•• As adopted by the Nantucket and Madaket Harbors Action PlanAs adopted by the Nantucket and Madaket Harbors Action PlanMinimum Criteria Applicable to All Surface Waters in MassachusettsParameterStandardAestheticsAll 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; turbidity; or produce undesirable or nuisance species of aquatic life.Bottom Pollutants or AlterationsAll surface waters shall be free from pollutants in concentrations or combinations or from alterations that adversely affect the physical or produce objectionable odor, color, taste or chemical nature of the bottom, interfere with the propagation of fish or shellfish, or adversely affect populations of non-mobile or sessile benthic organisms.NutrientsShall not exceed the site-specific limits necessary to control accelerated or cultural eutrophication.RadioactivityAll surface waters shall be free from radioactive substances in concentrations or combinations that would be harmful to human, animal, or aquatic life or the most sensitive designated use.Toxic PollutantsAll surface waters shall be free from toxic substances in concentrations or combinations that would be harmful to human, animal or aquatic life or wildlife. This includes consideration of site-specific limits, human health risk levels and accumulation of pollutants (bioaccumulation).
Town of Nantucket OrganizationTown of Nantucket OrganizationTown of Nantucket AdministrationHealth DepartmentMarine and Coastal Resources DepartmentDepartment of Public WorksNantucket Planning OfficeWannacomet Water CompanyWater Quality Testing (Public Beaches, Potable Water)Public Health Regulations/ Permitting Estuaries ProjectWater Quality Testing (Harbors, Great Ponds, Streams)Estuaries ProjectMunicipal Sewers (Sanitary and Storm)Town of Nantucket Master PlanWater Quality Testing (Public Water Supply)
Progress MadeProgress Made•• Water Quality Initiative WebsiteWater Quality Initiative Website•• Catalog of Water Quality Reports Within Catalog of Water Quality Reports Within TownTown
Coastal Management Coastal Management PrincipalsPrincipalsProgress UpdateProgress Update3/9/20113/9/2011
PurposePurpose►►To establish a set of best management To establish a set of best management principals for town owned coastal property principals for town owned coastal property and to use these principals for planning and and to use these principals for planning and as a guideline for private coastal property as a guideline for private coastal property owners.owners.
Current StatusCurrent Status►►Created coastal issue matrixCreated coastal issue matrixFormed from town department input and public Formed from town department input and public commentcommentIdentifies local departments and boards, state Identifies local departments and boards, state and federal agencies involvedand federal agencies involvedUpdated to matrix includes plans and programs Updated to matrix includes plans and programs in place to best integrate principals with on in place to best integrate principals with on going projects, plans and initiativesgoing projects, plans and initiatives
Example of Issue MatrixExample of Issue Matrix
Examples of Matrix Issues UnderwayExamples of Matrix Issues Underway►►Water QualityWater QualityWater Quality Initiative, Estuaries ProjectWater Quality Initiative, Estuaries Project►►Public AccessPublic AccessOne Big Beach, Roads and Right of Way One Big Beach, Roads and Right of Way Committee (e.g. Committee (e.g. SconsetSconsetBluff Walk Report)Bluff Walk Report)►►HarborsHarborsNantucket and Madaket Harbors Action PlanNantucket and Madaket Harbors Action Plan►►FisheriesFisheriesShellfish Management PlanShellfish Management Plan
Going forwardGoing forward►►More public involvementMore public involvement►►Creating a set of Creating a set of ““livingliving””coast management coast management principalsprincipals►►Creation of policy from the established Creation of policy from the established principalsprincipals►►Implementing coastal management Implementing coastal management principals in to towns planningprincipals in to towns planning
Siasconset Beach Preservation Fund
Proposal Summary & Background Information
Contents
Letter to Board of Selectmen
Proposal Summary & Illustrations
Project Area Maps
Comparable Projects
Community Feedback to Date
Assembled for
Nantucket Board of Selectmen
March 2011
DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT
Stabilizing the Coastal Bank:
Protecting Baxter Road and the
North Bluff in ‘Sconset
A Project Proposal from Siasconset Beach Preservation Fund
Since 1992, Siasconset Beach Preservation Fund (SBPF) has worked to preserve the
remarkable natural landscape of the ‘Sconset North Bluff and to protect Baxter Road and the
historic homes and bluff walk along its border. Despite those efforts, the eroding bluff has
continued to lose an average of three-four feet annually from north of Sankaty Lighthouse to
midway down Baxter Road. The lighthouse and seven homes have been relocated, and seven
other residences have been moved out of harm’s way to the edge of Baxter Road, on their
existing properties.
SBPF is proposing a system to ensure bluff stabilization and revegetation, and beach
preservation and protection of residences and Town infrastructure, in a way that will be
environmentally unobtrusive and effective.
Protecting Nantucket’s assets
It is now evident that cherished parts of the Island, including historic ‘Sconset Village,
will eventually disappear if the erosion trends of the last 60 years continue. Predictions of a
rising sea level and the unabated incidence of hurricanes and Nor'easter storms underscore
this peril. Baxter Road, the only access to Nantucket’s recently preserved Sankaty Head
Lighthouse and to many homes in that area, will likely be endangered, at significant cost to
the landowners and to the Town of Nantucket and its taxpayers.
This project simply protects—in accordance with state and local regulations—access
to Sankaty Head Lighthouse, the north end of Baxter Road and the existing community of
homes, many of which are historically important.
Our proposed approach for ending the adverse effects of erosion and damage to these
properties is designed for implementation without harming nearby beaches. This project is
similar to remedies that have successfully forestalled erosion on Nantucket and elsewhere. It
has been designed to function effectively and safely for many years to come, even as the sea
level continues to rise. It should demonstrate an easily maintained, environmentally sensitive
erosion control solution that will protect adjacent upland properties and Town infrastructure.
continued
DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT
Rev. through 12/20/2010 2
The project
This proposal involves placing strong but flexible geogrid-mesh containers called
marine mattresses and gabions on the ‘Sconset coastal bank, where temporary sand bag
terraces have already been permitted. Made of tough, high-tensile-strength polymeric
material, these water-filtering containers will be covered with beach-compatible sand.
The upper section of the system will be planted over with native vegetation to blend into the
landscape and to re-establish wildlife habitat lost to erosion.
The marine mattresses portion of the system consist of “mattress-shaped” containers
measuring 18-inches thick and filled with angular stones up to a half-foot in diameter.
These will be laid on the face of the coastal bank.
The gabion baskets are made of the same material formed into rectangular, box-like
shapes, each four-feet in height and filled with angular stones measuring approximately
one-two feet in diameter. These will be buried at the toe of the coastal bank to help
prevent sand from being scoured away from below where the marine mattresses are installed
(see illustration).
The beach-compatible sand covering the mattresses or gabions will regularly wash
away during large winter storms. This is a likely and desired development that replicates the
natural supply of sand being transferred by bank erosion to adjacent beaches. When this
happens, SBPF will replace the sand annually in late spring to once again cover the mattresses
and gabions. This will preserve the natural appearance of the bluff and beach. Additional
“sacrificial sand” will be deposited at the ends of the protected areas to mitigate against
additional scouring that might occur in those locations.
How it works
These stone-filled containers will be positioned on the face of the bank slope, so that
waves running up the bank will gradually dissipate during coastal storms. The installation will
follow the contours of the existing bank and provide a sand cover planted with native
vegetation on the higher bank face. This protected area will remain visually pleasing and
consistent with the appearance of adjacent natural coastal bank areas that have not yet eroded.
In large storms, when waves might otherwise wash up and undermine the sand at
the toe of the coastal bank, the gabions will absorb the impact of waves. Since these cages
filled with stones are porous, seawater will drain through them and flow back to the ocean.
The mattresses will extend up the bank approximately 18 feet above the beach, to stabilize
and protect the bank from erosion caused by strong storms of a “once-in-a-hundred-years”
magnitude.
The weight and size of the angular stones enclosed within the geogrid containers,
along with a rigorous anchoring system, will prevent them from moving, so that they cannot
be washed out to sea or swept along the coast, even during the strongest storms.
Sand that moves along the beach due to wave action, the process known as littoral
drift, will continue doing so without interruption from the installation. Through the littoral
drift process, new sand placed over and at the ends of the gabions will nourish adjacent
continued
DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT
Rev. through 12/20/2010 3
beaches as it washes away and is later replaced, thus continuing the natural beach
regeneration process.
A benefit of this particular mattress and gabion design is that it can be fabricated
off-site, transported to the site by truck or barge, and then placed accurately using
Nantucket-based equipment and labor. The installation will be readily maintained using
Island labor and machinery.
Proposed project location
This proposed installation will be located within the 2,500-foot section of the coastal
bank from 99 Baxter Road to 55 Baxter Road, running along roughly 10 properties north and
10 properties south of the intersection of Baxter Road with Bayberry Lane. Five or more
individual homeowners within the pilot area will install mattresses and gabions in front of
their properties, protecting some 500 – 1,000 feet of eroding bank.
A similar marine mattress system was installed on the north shore of Nantucket at
Hinckley Lane in 2005 (see photos). Already tested by several strong coastal storms, the
system has performed well in that location. Another was installed in 2007 on Martha's
Vineyard, under the direction of the Oak Bluffs Selectmen, to protect a threatened road.
That has also performed as promised and has provided the desired protection. In both
locations, no debris has been created and no further erosion or harm to neighboring beaches
has occurred.
The most extensive marine mattress protection of this kind in the Northeast U.S. was
installed at Cape May, New Jersey in 1996. Before being incorporated eight years later into
a much longer beach-fill effort, this installation served as the sole protection in its location for
commercial buildings, homes and critical infrastructure. During that initial period, this
approximately 500-foot long system successfully weathered several extreme storms with no
reported damage or loss of functionality, including after the particularly energetic 1997-1998
storm season that resulted in a Presidential Disaster Declaration. Many conservationists and
engineers consider systems like this to be among the most environmentally friendly of
effective erosion control methods when coupled with the regular replacement of washed away
sand. The systems on Hinckley Lane, at Oak Bluffs and in Cape May have required only
minimal or no repairs to their geogrid mattress and gabion structures.
This newly proposed project will be more secure and easier to sustain than other
systems. It clearly offers the potential of a long-term solution that preserves the bluff, protects
Baxter Road and the properties there, and naturally replenishes sand along the beach. Again,
the end result will be the long-term protection and preservation of ‘Sconset itself.
Paying for the project
Each abutting homeowner will decide whether to participate in the pilot project and
will pay the costs of its installation and maintenance through SBPF. An escrow fund, covering
the costs of possible removal if required, will be established and will be accessible by the
Town in the event that any property owner does not comply with maintenance agreements or
fails to replenish the sand as required.
The project has been conceived and designed to have no negative impacts on
neighboring beaches, the environment in general and the Island at large. Nonetheless, if the
overall project or an element of it fails or causes adverse effects, the stone-filled mattresses
and gabions can be readily removed, using similar local equipment and labor to what was
used in their installation. continued
DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT
Rev. through 12/20/2010 4
An island-wide challenge
SBPF has been in contact with other Nantucket shoreline homeowners who are
experiencing similar erosion problems. We’ve reached out to owners of property in
Madaket, Sheep’s Pond, Eel Point, Surfside, Dionis and elsewhere.
SBPF supports current efforts led by Joe Farrell, a marine resource management
specialist, and the Nantucket Planning and Economic Development Commission to test
movable barge-like structures to deflect the power of storm waves. They intend to “work with
Mother Nature” to redirect sand in order to widen threatened beaches.
Public input SBPF is currently consulting with a wide range of the Island’s leaders, to get their
input and questions about this proposed project so that we can address them before the
proposal is formally submitted to the required permitting agencies.
During this discussion period, while SBPF engages in informal talks before presenting
this project formally, SBPF will invite public questions and feedback. SBPF will also confer
with those who were active in the talks about the previous erosion management efforts, and
with other concerned citizens. Because we have incorporated concerns that people expressed
with our previous proposal, we are hopeful that our current plan will meet with approval from
some of our former opponents.
Next steps: The approval process
An extensive public review and permitting process will ensure that this proposed
project will be fully compliant with applicable regulations and performance standards, and
will make certain there are no adverse environmental impacts from the proposed project.
Timeframe
SBPF expects the outreach and permitting-approval process to require six to nine
months, including the following steps:
• Continue to conduct broad consultation on Nantucket and reach out to state and
federal agencies about the project design, which will likely occur over two to four
months.
• SBPF has submitted a warrant article to be considered at Annual Town Meeting in
April, authorizing the Board of Selectmen to grant permission to install the pilot
project on the town-owned beach. Assuming that the warrant article passes and that
permission is granted, SBPF will file a Notice of Intent (NOI) with the Nantucket
Conservation Commission and the Massachusetts DEP, and the formal approval
process will begin. SBPF anticipates several hearings over at least two months to
discuss the project and to respond to the commission, its staff and to public questions
and comments.
• Finally, we will apply for a U.S. Army Corps of Engineers permit and the associated
Coastal Zone Management Federal Consistency Certification.
For more detailed information or to comment on this proposal, please call Jenny Garneau at
508-325-0048. We welcome your inquiries.
DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT
Rev. through 12/20/2010 5
Anchored mattress & gabion system
DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT
Rev. through 12/20/2010 6
Marine mattress system installed on Hinckley Lane, Nantucket
Project Area
Figure 1USGS Locus
Siasconset Coastal Bank Stabilization and Beach Preservation Project Nantucket, Massachusetts
G:\Projects\Lighthouse\NOI\usgs.mxd
Basemap: 1972 USGS Quadrangle, MassGIS °0 1,000 2,000
Feet
1:24,000
1 inch = 2,000 feet
Bax
t
er
Rd60
70
80
75
60
4030
50
20
10
5
10
5
80
25
25
25
25
#85 (49-35) -- Lugosch
#63 (49-22) -- Singer
#99 (48-18) -- Furrow
#87 (49-8) -- Furrow
#97 (48-19) -- McQuade
#59 (49-20) -- Paine
#83 (49-34) -- Toucett
#73 (49-27) -- Hendrickson
#81 (49-33) -- Cohan
#79 (49-32) -- Weymar
#67 (49-24) -- Hearst
#77 (49-31) -- Posner
#55 (49-18) -- Hostetter
#93 (48-21) -- Freeman
#69 (49-25) -- Cowperthwaite
#75 (49-30) -- Osborn
#91 (48-22) -- Korengold
#65 (49-23) -- Tuttle
#71 (49-26.1) -- Merson
#61 (49-21) -- Vaughter/Gammon
5
10
30
15
60
20
20
20
30
80
50
40
70
40
75
50
20
80
40
50
15
75
40
70
3040
70
50
70
80
60
60 50
Figure 3Aerial Locus
Siasconset Coastal Bank Stabilization and Beach Preservation Project Nantucket, Massachusetts
G:\Projects\Lighthouse\NOI\aerial.mxd
LEGEND
Vertical Datum: North American Vertical Datum of 1988 (NAVD 88)Basemap: August 13, 2010 Orthophotography, Col-East, Inc.
Scale 1:2,1601 inch = 180 feet °0 90 18045Feet
Proposed Public Access (2010 Annual Town Meeting, Article 74)
5-foot Elevation Contour (feet above mean low water)
Initial Phase Participant
Private Parcel Boundary
Sconset Foot-path (Public Easement)
PROJECT BACKGROUND
A portion of the coastal bank in Siasconset, commonly
referred to as “Sconset", on the southeast coast of
Nantucket Island has experienced continued erosion which
has caused numerous homes and public infrastructure on
Baxter Road to be threatened as the setback from the top
of the coastal bank has continued to diminish. The
Siasconset Beach Preservation Fund (SBPF) has
investigated design alternatives for a coastal bank
stabilization project that would provide an
environmentally sensitive means to prevent storm damage
to these homes and public infrastructure due to continued
unabated coastal bank erosion while preserving the
coastal beach.
The Project area is an approximately one‐half‐mile long
section of coastal bank in Sconset from the vicinity of 55
Baxter Road to the vicinity of 99 Baxter Road, where the
Applicant is proposing to construct and maintain a coastal
stabilization system comprised of marine mattresses and
gabion baskets with a sand and vegetation cover (“Sconset
Project”).. The Project will preserve the coastal beach by
annually renourishing the sand coverage over the
stabilization system, thus maintaining a volume of sand
available to the beach and coastal system that will be
comparable to the volume that would otherwise be
available from the eroding bank absent the Project.
Although the approximate northern and southern
boundaries of the Project area are well‐defined, the
precise number of homeowners who will participate in the
Project is uncertain at this time; although there may be
fewer initial participants at the start of the Project, the
Proponent expects that up to 20 homeowners will likely
join the effort once success is demonstrated.
The coastal stabilization system was chosen as a result of
an Alternatives Analysis study performed by Ocean and
Coastal Consultants, Inc. (OCC) which determined that this
Project is the best option at this location for bank
stabilization while preserving the beach. This system will
run parallel to the shoreline. The design will also
incorporate gabion basket return walls at either end of
each continuous section of the system to protect the
exposed coastal bank in these areas from flanking erosion.
In addition to the beach compatible sand that will be
placed over the top of the system, the final design element
will consist of vegetating the upper bank slope to aid in
slope stabilization.
There are a number of comparable documented projects
including the following five which compare most closely
with the Sconset Project:
(1) Cape May, NJ Shoreline Protection Revetment;
(2) Nameloc Heights Gabions, Plymouth, MA;
(3) Hinckley Lane Bank Stabilization, Nantucket, MA;
(4) Seaview Avenue Bank Stabilization, Oak Bluffs, MA;
(5) Logan Airport Runway End Improvements, Boston, MA;
and
(6) Victor Larco Herrera Seawall Repairs, Trujillo, Peru.
COMPARABLE PROJECT OVERVIEWS
PROJECT NAME: SHORELINE PROTECTION REVETMENT
LOCATION: CAPE MAY STATE PARK, NJ
CONSTRUCTED: PHASE 1: 1996 / PHASE 2: 1997
Cape May Point is located on the mouth of the Delaware
Bay on the Atlantic Ocean. The objective of this project
was to provide dune protection in order to prevent the
loss of a number of commercial and residential buildings
as well as a road and other infrastructure that would have
resulted from continued significant erosion caused by both
coastal and ship generated wave action.
Phase 1 of the project was completed in 1996 and involved
the installation of several hundred feet of marine
mattresses, with the lower portion of the mattresses
extending down into the intertidal zone. For this phase, a
row of armor stones was placed seaward of the mattress
for added stability. In 1997 Phase 2 of the project was
completed. This phase extended the original project
approximately another 1000 feet along the adjacent
shoreline. Since some shifting and movement of the
mattresses had been observed at the Phase 1 site, the
Phase 2 design was modified to incorporate a crushed
concrete and core stone bedding layer in order to
minimize movement. In 2004, a beach nourishment
project completed by the US Army Corps buried the entire
mattress revetment.
In total, the marine mattress revetment was exposed for
eight (8) years before being covered by the beach
nourishment project. During the 1998 season, two
significant coastal storms impacted the project area. A
northeaster with wind gusts up to 60 mph on January 28
that year caused tidal flooding and beach erosion, which
exposed the mattresses, but neither they nor the dune
was negatively impacted by the approximate 4 foot storm
surge above the normal high tide.
A second northeaster storm on February 4 brought wind
gusts up to 73 mph, and caused extensive beach erosion
along the New Jersey shore with heavy rain and several
dune breaches. The highest tide was recorded at 9.5 feet
above MLW, the second highest on record for the beach
area. Again, the marine mattresses at Cape May were
exposed, but neither they nor the dunes were negatively
impacted by coastal erosion from the storm.
Cape May project site after completed construction but
prior to the beach nourishment project in 2004. (Photo
from Jeffery Gilbert, Philadelphia District, USACE CHETN
III‐72).
Current condition of Cape May project site, showing 2004
beach nourishment covering the marine mattresses
(Sept. 2010).
The project was noted to perform well and to stabilize the
dune as intended. Since the beach nourishment operation,
periodic sand fill is provided on an as‐needed basis to
maintain the beach. Since 2004, the mattresses have
remained covered, even during Tropical Storm Ernesto in
2006, which produced 80 mph winds and an all‐time high
wave height of 22.3 feet recorded by the Delaware Bay
Buoy.
Prior to the addition of beach nourishment to the project
area in 2004, the Cape May Project had a number of
similarities to the proposed Sconset Project including:
total project length, wave intensity, sacrificial sand
placement on top of the mattress system, and vegetation
planted on the bank for aiding stability.
The key differences between the Sconset proposal and the
Cape May project are that the Cape May installation
served to protect a dune, whereas the Sconset project is to
protect a much taller coastal bank. In addition, the
Sconset installation will use gabion baskets for toe
protection of the mattresses, in lieu of the large armor
stones used for Cape May. Furthermore, the Sconset
project will not include any beach nourishment; the only
sand fill proposed is a sacrificial berm to cover the
mattress installation and approximate the natural erosion
of the coastal bank.
PROJECT NAME: NAMELOC HEIGHTS GABIONS
LOCATION: PLYMOUTH, MA
CONSTRUCTED: 1991‐2007
The Nameloc Heights Project site is located on the east
facing coast of Cape Cod Bay along Nameloc Road in
Plymouth, MA. Four (4) homeowners have installed
gabion basket systems to stabilize the toe of the coastal
bank and prevent significant future erosion. Each
installation is approximately 100 feet long. The four
segments were constructed at various times during the
last 20 years. Additionally, each individual installation
borders adjacent properties which, to date, remain
unprotected.
Because these installations were not done simultaneously,
the projects exhibit some variation between each other. A
similar situation is initially expected to occur on the
Sconset project, since it is likely that not all residents will
participate. The southernmost gabion installation at
Nameloc Heights (Gabion #1), was completed in 2005 and
consists of PVC‐coated wire baskets and includes return
walls as part of the original installation. The slope above is
Current condition of Gabion #1 baskets installed 2005
(Oct. 2010).
well vegetated and the system is still performing well.
The Gabion #2 installation, completed after 2008, consists
of galvanized gabion baskets. This system also
incorporated return walls at the terminations and
additionally also includes sacrificial sand placed on top of
the structure. The upper slope contains some sparse
vegetation.
Current condition of Gabion #2 baskets installed 2008
(Oct. 2010)
The Gabion #3 installation, completed prior to 1991,
consists of PVC coated wire gabion baskets. The most
seaward row of baskets has been damaged due to storm
impacts and the onset of corrosion to the more vulnerable
wire gabion baskets. The slope above is very heavily
vegetated with mature plantings.
Current condition of Gabion #3 baskets installed pre‐1991
(October 2010).
The Gabion #4 installation was constructed in 2007 and
2008 and consists of galvanized wire gabion baskets. The
return structures are minimal and as a result heavy
flanking and erosion at the construction limits has
occurred.
Current condition of Gabion #4 baskets installed in 2007.
Note flanking and bank erosion at insufficient return
walls.
The main point of interest when comparing the Nameloc
Heights Project to the Sconset Project is observing the
impacts of constructing a discontinuous system. A similar
situation is expected to occur on the Sconset Project since
it is likely that not all residents will participate in the initial
phases of construction. Overall the gabion systems
constructed for the Nameloc Heights Project have
performed well. Unlike the proposed Sconset project,
however, the Nameloc gabion projects have not
performed any periodic sand nourishment. As a result,
some of the older installations presently display signs of
erosion flanking around the ends of the structure. These
are limited to those that do not include return walls or
those where the returns walls constructed are either
minimal or are inadequate to provide the necessary
protection. This case highlights the importance of
installing adequate return walls at construction
terminations as has been incorporated into the proposed
Sconset Project.
PROJECT NAME: HINCKLEY LANE BANK STABILIZATION
LOCATION: NANTUCKET, MA
CONSTRUCTED: 2005
The residential property at 28 Hinckley Lane is located
along the northwestern shoreline of Nantucket, MA. The
coastal bank was experiencing significant coastal erosion
which threatened the integrity of the existing dwelling. To
prevent erosion of the coastal bank from wave action, a
shoreline protection system was installed consisting of a
row of buried marine mattresses placed along the toe of
the coastal bank, with a single row of buried gabions as a
foundation for the toe of the structure. Sand cover that
was planted with native vegetation was constructed over
the marine mattresses and gabions to preserve the natural
look of the property. The sand cover, subject to erosion
from storm waves, provides a sacrificial sediment source
to nourish the beach. Additional erosion, which could
undermine the toe of the bank causing a slope failure of
the upper bank, is prevented by the installed marine
mattresses.
The sacrificial sand cover is reconstructed annually in the
spring to maintain the system and re‐cover any mattresses
exposed from winter storms. To date this installation,
completed in 2005, has been tested by several coastal
storms and thus far has performed as expected without
any major damage to the underlying gabions or
mattresses.
Hinckley Lane Project during construction (Nov. 2005)
The main similarity between the Hinckley Lane Project and
the proposed Sconset Project is the use of marine
mattresses on the lower face at the bank as the primary
stabilization element, coupled with the use of gabion
baskets to prevent the marine mattresses from slumping.
Additionally, the added elements of periodic nourishment
of the sand berm and a vegetated slope also parallel the
proposed project. Differences between the two projects
include a much shorter project length and lack of returns.
Hinckley Lane Project site after annual re‐nourishment
(April 2010).
PROJECT NAME: SEAVIEW AVENUE BANK STABILIZATION
LOCATION: SEAVIEW AVE., OAK BLUFFS, MA
CONSTRUCTED: 2008
This project is a stabilization project protecting the coastal
bank along Seaview Avenue in Oak Bluffs, MA. The
project consisted of a combination of marine mattresses,
gabion baskets and sand fill. Marine mattresses were
placed flat against the base of the embankment and were
then tied down to the soil below with helical anchors. A
single row of gabions was set on top of the lower end of
the mattresses to provide stability at the toe of the
embankment. Sand fill material was then placed over all
of the installed elements and coastal vegetation was then
planted to aid stabilization. The total length of the project
was approximately 180 feet. To date the project has
performed well.
The Seaview Avenue Project design elements and
methodology are similar to Sconset in that both projects
incorporate marine mattress for slope protection along
with gabion baskets for added stability at the toe of the
slope. Additionally, both projects utilize sand cover and
coastal vegetation to provide further stability of the slope.
The main difference is that the project length for Seaview
is much shorter and also return walls have not been
utilized.
Seaview Avenue Project during construction (April
2008).
Seaview Avenue Project site after of completed
construction (May 2008).
PROJECT NAME: LOGAN AIRPORT RUNWAY END
IMPROVEMENTS
LOCATION: BOSTON, MA
CONSTRUCTED: early 1990’s
This project involved placement of marine mattresses at
the end of Logan Airport runways that abut the waters of
Boston Harbor. The mattresses were placed in a
revetment type application at the ends of Runways 22L
and 27 to yield a more gradual slope between the runway
end and the water, in response to guidelines from the FAA.
The mattresses were placed at an elevation where they
would serve to dissipate the force of wave run‐up during a
storm surge.
Mattresses were provided in lengths ranging from 15 feet
to 30 feet. The typical height of the mattresses was ten
inches. The size of the stone fill raged from 1.5 to 3.5
inches. Lengths of installation were a few hundred feet.
The Deputy Director of Environmental Planning and
Permitting at Massport indicated that the marine
mattresses have performed very well over their nearly 20‐
year history. Recently, they identified one steeper area
where a little maintenance is needed to repair some of the
ties. Such maintenance is expected; the Sconset project
includes annual inspection of the system and periodic
repairs, as necessary. Massport is in the process of
undertaking another installation at one of the other
runway ends, using more of a gabion (rectangular design)
than the earlier marine mattresses.
The project is similar to the proposed Sconset project in
that it includes marine mattresses in the coastal
environment as the primary stabilization element.
Differences between the two projects include that no
gabions were utilized in the Logan airport project, a much
shallower slope exists at Logan airport, and the lengths of
installation were much shorter.
PROJECT NAME: VICTOR LARCO HERRERA SEAWALL
REPAIRS
LOCATION: TRUJILLO, PERU
CONSTRUCTED: 2008
Marine mattresses and gabions were installed for the
Victor Larco Herrera project located in the province of
Trujillo, Peru. The project consisted of repair and
protection of a failing, crumbling seawall. The seawall
structure was failing as a result of scour at the toe and the
use of unreinforced construction.
Marine mattresses were installed along several sections of
the seawall, and provided a lower cost alternative to
reconstructing the stone and masonry seawall in‐kind.
Toward the southern end of the project site the existing
seawall had already failed completely. In that area, marine
mattresses were placed on grade and gabion baskets were
used to provide both a stable foundation and scour
protection.
In general the project has performed well. One small
segment of the gabion system had minor damage due to
large stones impacting the gabion surface during a storm
event. The damaged sections of the marine mattresses
were relatively small in comparison to the size of the
overall project, and were easily repaired. The project has
been a success and demonstrates that this type of design
can withstand heavy wave activity.
There are two major differences between the Victor Larco
Herrera Project and the proposed Sconset Project. The
first is that the Victor Larco Herrera project did not
incorporate coverage by sacrificial sand as part of the
project scope. As a result, the elements constructed are
more exposed to coastal effects. Secondly, the geogrid
used for construction of the gabions was a weaker biaxial
(BX) grid, whereas the geogrid to be utilized for the
proposed Sconset installation will be of a much higher
tensile strength uniaxial (UX) grid. The main similarity
between the two projects is the level of wave activity that
each site is exposed to. Both are coastal applications and
both are subjected to potentially very high energy wave
action, particularly during coastal storm events.
Gabion baskets and marine mattresses were used to
replace a deteriorated seawall in Victor Larco Herrera,
Peru. Marine mattresses at the base of the seawall were
buried by natural processes.
Victor Larco Herrera Project, showing gabion basket
installation.
Victor Larco Herrera Project, showing damage to gabion
baskets from coastal storm events.
SUMMARY OF BANK STABILIZATION PROJECTS PROJECT NAME PROJECT LOCATION PROJECT OWNER PROJECT LENGTH INSTALLATION DATE DESIGN COMPONENTS SACRIFICIAL SAND VEGETATIVE SLOPE FREQUENCY OF SAND SUPPLEMENT Cape May Shoreline Protection Revetment Cape May State Park, NJ New Jersey Department of Transportation (NJDOT) Phase 1: 850 feet Phase 2: 980 feet Total: 1830 feet Phase 1: 1996Phase 2: 1997 Beach Nourishment: 2004 Marine Mattresses and Toe Armor Stones Y (Post 2004) Y (Post 2004) As Required Nameloc Heights Gabions Nameloc Road Plymouth, MA Residential (4 Owners Participated from 1991 through2008) 400 feet Gabions #1: 2005 Gabion #2: 2008 Gabion #3: 1991 Gabion #4: 2005‐ 2007 Gabion #1: PVC‐coated wire baskets Gabion #2: Galvanized wire baskets Gabion #3: PVC‐coated wire baskets Gabion #4:Galvanized Wire baskets Gabion#1:Y Gabion#2: Y Gabion#3: Y Gabion#4: Y Gabion#1: Y Gabion#2: Y Gabion#3: Y Gabion#4: Y Sacrificial sand placed one time only (at time of system installation) Hinckley Lane Bank Stabilization 28 Hinckley Lane Nantucket, MA R. Patton 80 feet 2005 Marine Mattresses Y Y Yearly Seaview Avenue Bank Stabilization Seaview Avenue Oak Bluffs, MA Town of Oak Bluffs 180 feet 2008 Marine Mattresses andGabion Toe Protection Y Y Not Known Victor Larco Herrera Seawall Repairs Victor Larco Herrera Trujillo, Peru District of Victor Larco Herrera Unknown 2010 Gabion Baskets and Marine Mattresses installed at grade N (only coverage by natural processes) N N/A Siasconset Coastal Bank Stabilization & Beach Preservation Project Baxter Road, Nantucket MA Siasconset Beach Preservation Fund, Inc. 2500 feet Permitting Phase Marine Mattresses and Gabion Toe Protection Y Y Annually, As Required
February 2011
Siasconset Beach Preservation Fund
18 Sasapana Road
Nantucket MA 02554
Nantucket Community Leader
1234 Main Street
Nantucket MA 02554
Dear Fellow Nantucketer,
Thank you for taking time recently to talk with those of us involved with Siasconset
Beach Preservation Fund. As we search for ways to save our Nantucket homes from being
further endangered or destroyed by erosion, we highly value your input and advice on our
continuing efforts.
We’ve listened closely to what you’ve told us. After meeting the past few months with
over 50 island leaders, we wanted to share some of the feedback we’ve received so far about our
new project idea, as well as on our past efforts.
As you now know, our newest proposal is small in scale and involves “baskets” of large
stones anchored into the bluff then covered with natural beach sand. The sand is expected to
wash away at the same rate that the beach and bluff are currently eroding. Because new sand will
be supplied annually, neighboring beaches will receive the same amount of sand as they
currently do in the natural process of sand moving along the beach.
In fact, the system we are proposing is already being tried on Nantucket and in other
ocean front communities, with notable success. In essence, the new plan is a more robust version
of the large sand envelope system being used successfully within the project area over the past
three years by six property owners.
In our new proposal, we’ve taken special care to avoid any threats to fishing and sporting
activities dependent on our marine environment. We want to be sure that any erosion
management efforts be done in ways that cause no harm to the environment. This system is
designed for minimal impact and could be easily removed. Individual homeowners along with
SBPF will bear all the financial risks and will guarantee maintenance or removal of the
individual installations.
Others on Nantucket might also benefit from our efforts. Erosion is an increasing
concern in many locations around the island. This project could be instructive for other local
homeowners, businesses and Town of Nantucket infrastructure, as one safe and sensitive way to
address what we all know is a continuing environmental problem. All of us on Nantucket would
be better off for it helping to keep the Island as we know and love it.
We’ll continue talking to you, and we hope you’ll keep your mind open as we continue
our efforts. Attached is a summary of what we’ve learned from our various meetings, lessons
that we are trying to incorporate into our current proposal and future dialogue. This will guide us
as we continue, prior to formally introducing the plan at some point in the future. We thought
you would be interested. Meanwhile, feel free to contact any of us with your further thoughts and
concerns.
Sincerely,
Caroline Ellis (carolinequaise@gmail.com) Bob Felch (RDFELCH@aol.com)
Josh Posner (joshposner@comcast.net) Kermit Roosevelt (kroosevelt@verizon.net)
Beth Singer (bethsinger@aol.com) Helmut Weymar (helmut@weymars.com)
Siasconset Beach Preservation Fund
Community Feedback 2010-2011
Here are the notable comments, questions and concerns that we’ve
heard from those with whom we’ve spoken about the design of our newly
proposed project. We’ve made a special effort to listen to the strongest, most
skeptical critics. Rather than dwell on the past, this document is an effort to
focus on the future as the best way to respond pragmatically to past criticisms.
We highlight below the ways in which the new project responds to the
comments that we’ve heard.
Size and impact of the project
• Although some recognize that we’ve had modest success with the
current permitted temporary terraces, parts of our earlier dewatering
system created unsightly and sometimes dangerous debris, and we took
too long to remove it.
The baskets and gabions in this new system should stay firmly
anchored in place. No fabric that might tear and wash out to sea is used
in this system. Nothing in this project requires sand from neighboring
beaches or sand dredged from the ocean. Both the anchor rocks and
sand are brought to the site, preferably from Nantucket quarries, or from
compatible off-island sources.
Our current temporary jute terraces are well anchored to the bluff,
and since that system design was changed, those have not washed
away in over two years and have not had a negative impact on
neighboring properties. We had a serious problem with our previous
design, with small bags and 4” x 4” braces that washed away in a major
storm. We understand that those unfortunate circumstances have done
more to harm our reputation than anything else we have tried over the
past 18 years. (As those who have investigated it agree, the sand bags
washing up and harming our island in recent months do not come for the
‘Sconset temporary terraces.)
• Our last proposal disregarded potential impacts on sport fishing and
recreation.
This system should have no effect on fishing. Nothing will be installed
that might float into waterways where boats travel. Nothing requires
Siasconset Beach 2
access via the water. No excess sand will cover cobble-bottom habitat.
Unlike our previous beach nourishment proposal, this project will have
much less overall impact on the environment. (We intend to have a
sample gabion and mattress on island for inspection sometime soon.)
By revegetating the installations with natural planting and
replacing sand when needed, the beach will appear mostly natural,
causing no impediment to hikers, bathers and other recreational users
who might visit the beach. The beach area should remain mostly intact.
In fact, except at a few of the northern most homes on Baxter Road, the
look of the bluff might improve to look more like the historic, fully-
vegetated bank—especially when compared to the current denuded,
exposed bank with visible sewer pipes from a bygone time.
Questionable benefits and costs
• Nantucket residents understand our desire to save our homes, but some
think that SBPF exaggerates the potential damage that continuing
erosion might cause to public ways and structures, including Sankaty
Light, the village of ‘Sconset, the Bluff Walk and the Baxter Road
thoroughfare.
We know that some of you feel strongly that natural forces should
be respected and accepted. On the other hand, who among us would not
try to save our mid-island home from a hurricane or a flood? We’re up
against similar destructive natural occurrences in ‘Sconset, although in
our case these forces are almost unrelenting rather than periodic.
Historic photos show how much of the shoreline has already been
lost in the area. Eventually, perhaps within our lifetime or that of our
children, much more of the area will be washed away including access to
the lighthouse and Baxter Road itself.
With the expected participation of three homeowners, the
northern-most section of the bluff walk would be protected by the pilot
project. Without protection, the erosion that has recently begun at the toe
of the bluff in this area would likely result in closing another section of the
bluff walk within a year or two.
We don’t believe that an irreconcilable conflict exists between
respecting Mother Nature and taking reasonable steps to protect our
homes from erosion. As with most things in life, it is a question of striking
the right balance. We think most Nantucketers would agree with this
balanced approach.
Other parts of our island face similar erosion threats, and we think
this project could be instructive in those circumstances. We will
encourage scientists and researchers to evaluate the effectiveness of
our efforts and will explore finding an academic partner to maximize what
Siasconset Beach 3
can be learned. We will make our engineering plans and decisions
completely transparent and will seek alternate engineering evaluations,
including those suggested by others.
We support island-wide erosion efforts, not just in ‘Sconset. We
think this project might help point the way to a beach erosion control
method that’s both effective and has negligible impact on the
environment compared to recent failed efforts.
• Many of you are concerned about potential costs to the public.
Nothing in this proposal should cost the Town of Nantucket
anything beyond the usual administrative planning and oversight that’s
required for similar projects.
Our homeowners will bear the entire costs of our planning and
installation. An escrow fund will be set up to ensure complete removal of
any elements of the project if that’s deemed necessary.
Every year the assessed values for homes on upper Baxter Road
go down and the abatements go up. We estimate that the impact of
erosion has cost the Town over $500,000 in property taxes over the last
10 years, taxes that have been shifted onto the rest of the island’s
taxpayers. This cost is increasing every year as more Baxter Road
properties lose value.
How others see us
• Some of you thought it was confrontational, secretive and divisive to file
a warrant article seeking repeal of the moratorium now in place.
SBPF filed the citizen warrant article because we thought that
work on the Coastal Management Plan (CMP) was no longer moving
forward. We were informed that principals of the CMP had been
formulated and, indeed, the plan was completed. Since filing our article,
we have been told that the Town wishes to do more work on the CMP.
Of course, we want to make progress in efforts to save our homes,
and we filed the article out of that concern. We’re now working
cooperatively with the Town Administration on the development and
adoption of a CMP.
• After problems with our earlier effort, some of you have a very negative
view of SBPF and its members. Some thought we were insensitive to
public concerns and were “arrogant” in our approach.
Siasconset Beach 4
We regret, as much as anyone else, the ill will and rancor that
arose during our beach nourishment proposal. No one benefited from
that. Although we don’t unreasonably expect to win over everyone to
supporting our efforts, we are especially disappointed that some on
either “side” thought of this as an adversarial, “we-versus-them” situation.
We acknowledge that we were a major contributor to this scenario, but
we trust that we can move forward in a more constructive mode.
We consider ourselves to be neighbors, friends and part of our
entire island community. We are avid and steady supporters of what
makes Nantucket so special. Our homeowners serve on Nantucket’s not-
for-profit boards. We contribute to important Island organizations like
Nantucket Cottage Hospital, Nantucket Boys & Girls Club, Friends of
Nantucket Public Schools, Nantucket Historical Association and many
others.
Our Nantucket homes mean more to us than just the real estate
involved. They’re part of Nantucket’s historic assets and community
fabric. As have many Nantucket families, most of ours have spent many
years—several generations in some cases—enjoying Nantucket during
the summer and all year round. Although we hope to continue trying to
save our homes, we want to be sure to do it in ways that most
Nantucketers can support.
What’s ahead?
Besides the time that we’ve spent with each of you, we’re already
working with the Town Administration and the Nantucket Planning and
Economic Development Commission for guidance. If a comprehensive Coastal
Management Plan is the best way forward for the entire island, then we’re
happy to work on that effort, although we understandably consider that time is
of the essence.
We’ll also continue to work diligently explaining to the public what we’d
like to do, with our commitment to making the best effort at being transparent.
We’ll make available to the public any of our charts, graphs, engineering plans
and samples of the material that we propose to use. We’ll sit down and talk
through all of the options available and how we might work with any of
Nantucket’s oversight groups.
In sum, we want to work cooperatively with others on our island in a way
that will help us save our homes while causing no harm and, ideally, being
helpful to preserving Nantucket as we all know and love it.
Caroline Ellis (carolinequaise@gmail.com) Bob Felch (RDFELCH@aol.com)
Josh Posner (joshposner@comcast.net) Kermit Roosevelt (kroosevelt@verizon.net)
Beth Singer (bethsinger@aol.com) Helmut Weymar (helmut@weymars.com)
ARTICLE 33
(Appropriation: Sewer Capital Debt Repayment)
To see if the town will vote to appropriate a sum of money from the tax levy or
other general revenues of the town to pay to the Sewer Enterprise Fund to cover the
complete debt service payments applicable to loans from the State Revolving Fund for
the construction of the Surfside and Siasconset Wastewater Treatment facilities, and
further to see if the town will vote to meet this appropriation by raising and appropriating
or transferring from available funds such sum of money, subject however, to a favorable
vote of the town for a debt exclusion ballot question to exempt this amount from the limits
upon taxes pursuant to Proposition 2 1/2 so-called (G. L. Ch. 59, s. 21C(k)), or take any
other action related thereto.
(Timothy M. Soverino, et al)
ARTICLE 45
(Appropriation: Construction of Wind Turbine(s) on Landfill Site)
To see if the Town will vote to raise and appropriate, transfer from available funds
or borrow pursuant to any applicable statute a sum of money to be expended by the
Town Manager with the approval of the Board of Selectmen, for professional services in
connection with the design, permitting, construction, engineering, construction
supervision and other related professional services for the construction of up to three (3)
wind turbines on the following Town property:
Map Lot Number Street
39 14 188 Madaket Road
58 1 Massasoit Bridge Road
58 38 Madaket Road
Or to take any other action related thereto.
(Board of Selectmen)
ARTICLE 113
(Real Estate Conveyance: Industrial Land)
To see if the Town will vote to authorize the Board of Selectmen to sell, convey or
otherwise dispose of the fee or lesser interests in all or any portion of Lots F, G, I and N
as shown on a plan entitled “Subdivision Plan of Land” dated May 10, 2010 on file at the
Nantucket Registry of Deeds at Plan No. 2010-62, subject to Chapter 30B of the
Massachusetts General Laws and a finding by the Board of Selectmen that such sale,
conveyance or release furthers community planning and environmental protection goals.
All as shown on a map entitled “2011 Annual Town Meeting Warrant Article 113” dated
January 2011 and filed herewith at the Office of the Town Clerk.
Or to take any other action related thereto.
(Board of Selectmen)