HomeMy WebLinkAbout20230523 NOI_Part 2_Locus_Narrative
NOTICE OF INTENT – MAY, 2023 Foth
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
EXHIBIT A
Locus
EXHIBIT A - LOCUS
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
COTUIT, MA
NOTICE OF INTENT – MAY, 2023 Foth
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
EXHIBIT B
Project Narrative
NOTICE OF INTENT – MAY 2023 Foth · 1
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
EXHIBIT B
PROJECT NARRATIVE
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
COTUIT, MA
1. General Overview
The Town of Barnstable (Town), acting through it’s Department of Public Works, is submitting a
Notice of Intent (NOI) and supplemental documentation to conduct a maintenance dredging
project in Cotuit Bay (see Locus Map, Exhibit A and Figure 1 below). The proposed project consists
of dredging the existing 8 foot deep Cotuit Bay Entrance and 10 foot deep Cotuit Bay Embayment
Channels to restore safe navigation to the active waterfront area that supports recreational and
commercial boating needs. Vessel access and navigational safety are currently compromised due
to shoaling presently observed within the Cotuit Bay Entrance and Embayment Channels.
Figure 1: Site Locus
The Entrance and Embayment Channel limits and depths proposed for this project are consistent
with those previously authorized in 1998/2001 and 2009 (see Section 3, Dredge Site History).
The dredging authorized in 1998/2001 was for a total of ±225,000 cubic yards (CY), and also
included the dredging of the Cotuit Inner Embayment Channel, West Bay Entrance Channel, and
Seapuit River Channel. In 2009, maintenance dredging was once again authorized for the removal
of a total of ±15,850 CY from the Cotuit Bay Entrance and Embayment Channels and with the
beneficial reuse of sediments at Dead Neck Beach as nourishment. The proposed maintenance
project will consist of dredging a total combined area of ±210,550 square feet (SF) (±4.83 Ac) and
an estimated ±18,649 CY of sediment, including 3H:1V sideslopes and a 1-foot allowable
overdredge. The Cotuit Bay Entrance Channel will be restored to its’ previously authorized
footprint to -8.0 feet Mean Lower Low Water (MLLW) with a one (1) foot allowable overdredge to -
9.0 feet MLLW and approximate 3H:1V sideslopes. The Cotuit Bay Embayment Channel will also
be restored to its’ previously authorized footprint to -10.0 feet MLLW with one (1) foot allowable
overdredge to -11.0 feet MLLW and 3H:1V sideslopes.
Dredging will be performed via hydraulic methods using the Barnstable County Dredge Program’s
cutter suction dredge Sandshifter, an Ellicott “850 Bay Dragon” style dredge. The dredge will
pump a continuous “slurry” consisting of sandy sediment and seawater through approximately
DEAD NECK BEACH
NOURISHMENT AREA
10’ EMBAYMENT
CHANNEL
8’ ENTRANCE
CHANNEL
NANTUCKET SOUND
COTUIT
BAY
WEST
BAY
NOTICE OF INTENT – MAY 2023 Foth · 2
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
±11,000 linear feet (LF) of HDPE pipe to the eastern most end of Dead Neck for beneficial reuse
as nourishment along the barrier beach and to restore the breach that occurred in late December
2022 between the West Bay jetty. A booster station will be used in-line with the pipeline as
needed to achieve the full pumping distance. A temporary containment area will be constructed
above Mean High Water (MHW) using existing beach sand. The containment area will consist of
an excavated trench approximately 450 foot long by 60-foot wide with a low grade perimeter
berm that will extend along the foreshore and return landward to tie into the backland dune.
Slurry will be discharged from dredge pipeline into the containment area to allow for suspended
sediments to settle out and seawater to percolate/return back into the beach/Nantucket Sound.
Dewatered sediments will be moved from the temporary containment area using a front-end
loader with rubber tires and then placed/spread along the eastern-most 800 linear feet (LF) of
Dead Neck to the West Bay jetty. The beneficial reuse of dredge sediments will restore the
breach between the West Bay jetty and re-nourish eroded dune and forebeach areas along
Nantucket Sound. Sediments will be placed along Dead Neck to within previously authorized
elevations and slopes, with the crest of the berm tying into existing dune elevations. All slopes
along the foreshore beach will be graded to 10H:1V to accommodate shorebird nesting habitat
with the toe ending at Mean Low Water (MLW).
Construction is anticipated to start in mid to late October of 2023 and be completed prior to
January 15, 2024.
1.1 Site Description
Cotuit Bay is located on the south side of Cape Cod, MA and connects to Nantucket Sound by an
existing tidal inlet, composed of the Cotuit Bay Entrance and Embayment Channel. From offshore,
the Entrance Channel approaches Cotuit Bay on the west side of Sampson’s Island, before
transitioning into the Embayment Channel, which wraps around Sampson’s Island and continues
into the Cotuit Inner Embayment Channel (not proposed as part of this project) that leads into
Cotuit Bay. Cotuit Bay is a part of the Three Bays region of Osterville, MA, which also includes
North Bay and West Bay. Navigational concerns of shoaling in the channel and poor navigability
at low to mid-tide were identified by the local Harbormaster. A combined hydrographic and
topographic survey was conducted on March 18, 2022 to assess existing depths within the
existing Cotuit Bay navigation channels which confirmed the need for maintenance dredging.
The Cotuit Bay Entrance Channel is a 100-foot wide by 3,150 foot long approach channel that
was most recently authorized in 2009 to a depth of -8 feet MLLW (see Section 3, Dredge Site
History for complete list of authorizations). The shoaling in this channel is presented in Exhibit E,
Permit Plans. A TIN-TIN volume computation between the March 18, 2022 survey and the 8 foot
Entrance Channel prism shows ±14,863 CY of material available, including overdredge and 3H:1V
side slopes.
The Cotuit Bay Embayment Channel is a 100-wide by 1,624 foot long channel that curls around
the western tip of Sampson’s Island, where dynamic littoral processes are known to occur. The
embayment channel was most recently authorized in 2009 to a depth of -10 feet MLLW (see
Section 3, Dredge Site History for complete list of authorizations). The proposed shoals to be
dredged are shown in Exhibit E, Permit Plans. A TIN-TIN volume computation between the March
18, 2022 survey and the 10 foot Embayment Channel prism shows ±3,786 CY of material
available, including overdredge and 3H:1V side slopes.
Dead Neck is a barrier beach that separates the Seapuit River from Nantucket Sound and
provides storm damage protection and flood control for the river and adjoining upland areas.
Dead Neck also supports wildlife habitat for migratory bird species and other organisms native to
barrier beaches and coastal dunes. The island remains undeveloped, and is referred to as
“Protected Open Space” in the Town of Barnstable’s Local Comprehensive Plan, dated 2010.
NOTICE OF INTENT – MAY 2023 Foth · 3
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
Dead Neck (Parcel ID: 050002) and has been owned since 2004 by the Three Bays Preservation,
Inc. (TBPI), which was formed in 1996. Dead Neck was formerly attached to the mainland of Cape
Cod at the eastern end. In 1901, a channel was dug (West Bay Entrance Channel) to provide
access for boats into West Bay. The channel is bounded by two stone jetties, which were installed
by the state on state property. These jetties and other structures to the east create barriers that
inhibit the westward littoral drift of sand to Dead Neck. With the littoral sand source cut off by the
jetties, Dead Neck suffers excessive erosion unless it receives periodic nourishment. A study
conducted in 2013 showed that the jetties result in an annual loss of approximately 12,000 CY per
year and a corresponding accumulation of material in the Cotuit Bay Entrance Channel at the
west end of Sampson’s Island due to the predominant east-to-west sediment transport along the
shoreline.
The Project Site is located within the following FEMA Flood Zones: Cotuit Bay Entrance and
Embayment Channels fall within Zone VE El. 16 (18.15 feet MLLW), Zone VE El. 14 (16.15 feet
MLLW), and Open Water Zone as presented in Map 25001C0756J (Effective date 7/16/2014);
Dead Neck Nourishment Area falls within Zone VE El. 16 (18.15 feet MLLW) and Zone VE El. 15
(17.15 feet MLLW). The entire project site, including the channels and Dead Neck lie within
Coastal Barrier Resources System (CBRS) Areas established 10/1/1983 and 11/16/1990. FEMA
Flood Insurance Rate Maps for the project can be found in Exhibit D.
The tidal datum for this project has been established using NOAA’s VDatum Online, Version 4.5.1,
as follows: Mean Lower Low Water (MLLW) = 0.0 feet; Mean Low Water (MLW) = +0.25 feet;
Mean High Water (MHW) = +3.35 feet; and Annual High Tide Line (AHTL) = +4.60 feet. The
conversion between the North American Vertical Datum of 1988 (NAVD88) to MLLW is +2.15
feet.
1.2 Project Need & Purpose
Periodic maintenance dredging is required to restore safe navigation and access to/from Cotuit
Bay and Nantucket Sound. The channels are used year round by commercial and recreational
boaters and provide access for marinas, boat yards, charter boats, fishing boats, and pleasure
craft. Many businesses within the Three Bays Region depend on safe and navigable waters, thus
the shoaling that has occurred may have economic impacts to the surrounding areas. If dredging
is not performed, the channels will continue to accrete sediments and will pose an even greater
threat of vessel groundings with the channels potentially becoming unusable even during the
higher tide cycles.
Additionally, beach nourishment is periodically required on Dead Neck to restore the barrier beach
and dune system to its most effective and natural elevations and slopes. In December 2022, a
significant storm event washed out the area directly adjacent to the west of the West Bay jetty on
the island, leaving a breach within barrier beach system. This breach, if not renourished, has the
potential to rapidly increase the rate of erosion of the barrier island, as water and waves can
easily overtop the beach/dune during higher tide cycles and storm surge events. As stated above,
the breach area historically experiences excessive erosion unless it receives nourishment.
Mitigation of the erosion along Dead Neck has been necessary and on-going since approximately
1934. Dead Neck provides important habitat for migratory birds and other organisms, so erosion
reduces the ability of the eastern portion of the island to maintain habitat for animal nesting and
foraging, as well as provide storm damage prevention for inland areas.
1.3 Scope of Work
All dredging activities to be performed will consist of maintenance within previously
authorized/dredged limits and depths. No improvement dredging is being proposed as part of
this project.
NOTICE OF INTENT – MAY 2023 Foth · 4
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
The Cotuit Bay Entrance Channel will be dredged to -8 feet MLLW with a one (1) foot allowable
overdredge to -9 feet MLLW. The Cotuit Embayment Channel will be dredged to -10 feet MLLW
with a one (1) foot allowable overdredge to -11 feet MLLW. All dredging will include 3H:1V
sideslopes.
Including the overdredge and sideslopes, the Cotuit Bay Entrance and Embayment Channels
require the removal of ±14,863 CY and ±3,786 CY of sediments, respectively, to restore navigation
to authorized depths, for a total of ±18,649 CY. A full breakdown of dredge volumes and areas
based upon the survey conducted on 3/18/2022 is presented below in Table 1.
Table 1: Proposed Dredge Area & Volume Computations
Location
Dredge Depth
(Feet below
MLLW)
Dredge
Area
(SF)
Dredge Volume
to Design
Depth
(CY)
1’ Allowable
Overdredge
Volume
(CY)
Total
Dredge
Volume
(CY)
Cotuit Bay
Entrance
Channel
8.0
167,895
7,976
6,887
14,863
Cotuit Bay
Embayment
Channel
10.0
42,655
1,964
1,822
3,786
Total
210,550
9,940
8,709
18,649
Dredge areas and volumes include 3H:1V sideslopes as shown on Permit Plans; SF = square feet; CY = cubic yards
The proposed nourishment at Dead Neck will be performed within previously
authorized/nourished limits, slopes, and elevations. Dredge sediments from the Cotuit Bay
Entrance and Embayment Channels will be delivered to the eastern end of Dead Neck via a
temporary slurry pipeline. Once the slurry has reached the nourishment site, it will be dewatered
in a temporary settling/dewatering containment area. The proposed dewatering methodolgy has
been an effective method used at this site and was most recently utilized for the Cotuit Cut-Dead
Neck Sampson Island (DNSI) project which was performed in three phases from 2019 to 2021
under USACE Permit #NAE-2013-02073, MADEP Ch 91 Permit #14437, MADEP 401 WQC
#X264968, Wetlands File #SE-003-5053, and MESA Conservation Permit #017-295.DFW. An
approximate 450-foot long by 60-foot wide temporary dewatering area will be constructed
immediately west of the proposed nourishment area. The containment area will be bound by the
existing dune and a temporary man-made sand containment berm to be constructed above MHW
using existing beach sediments. The sediment slurry delivered through the pipeline will be
allowed to naturally settle and dewater, and dried sands will be placed in the nourishment area by
front-end loader or similar earth moving equipment. Following the completion of work, the
temporary containment area will be restored to preconstruction conditions.
The proposed nourishment template will be located on the Nantucket Sound side of Dead Neck
and commence at approximately MLW (+0.25 feet MLLW) and then extending landward at a
10H:1V slope until it reaches the proposed berm crest elevation of +12 feet MLLW. The berm
crest will vary in width consist of a level bench that extends landward to match the grades of the
existing dune. The proposed nourishment template will extend from the West Bay jetty at the east
end of Dead Neck and continue west for a total distance of ±800 LF. The proposed nourishment
template has been designed to be within elevations and slopes previously authorized in 2001 and
to support nesting bird habitat. The total proposed Dead Neck Beach Nourishment template has
an approximately ±128,132 SF footprint.
NOTICE OF INTENT – MAY 2023 Foth · 5
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
All work proposed for the project will be conducted during the time of yeat when biological
activity is least active and within the Time Of Year (TOY) restrictions established by local, state
and federal regulatory agencies. Species of concern are anticipated to include, but may not be
limited to, Winter flounder, Horseshoe crabs, Quahogs, Piping Plover and Least Tern. It is
anticipated that work will mid to late October 2023 and will be completed prior to January 14,
2024.
2. Site Usage and History
Cotuit Bay, and the Three Bays Region, has historically provided and continues to be a gateway
for both recreational and commercial vessels to/from Nantucket Sound. The proposed areas of
dredging being pursued by the Town are shown in the Permit Plans provided in Exhibit E.
Maintenance dredging is required on a periodic basis to restore/provide safe access within and
use of navigable waters that benefit the general public.
Dead Neck is an essential element to the southern shoreline of Cape Cod. It was once attached to
the mainland but is now a barrier beach island and provides ample protection of wildlife habitat
and nesting habitat for waterbirds of high conservation priority. The entirety of the island is
classified as priority habitat for rare and endangered species by the Massachusetts Natural
Heritage and Endangered Species Program (NHESP). Dead Neck has historically been home to
populations of Piping Plovers and supports a diverse array of nesting waterbird species. Dead
Neck also serves as a pre-migration fall staging area for Common Terns and Roseate Terms, as
well as many shorebird species. Dead Neck provides flood control and storm damage protection
for the bays and estuaries to the north. Beach nourishment is beneficial to the Dead Neck system
by restoring lost dune and beach areas that provide ample habitat for bird nesting and foraging
habitat, as well as protect lands and waterbodies to the north from coastal threats.
2.1 Due Diligence Assessment
A due diligence assessment was conducted and completed as part of the Town’s 10-year
Comprehensive Dredge Permit (CDP) which is currently pending the initiation of the regulatory
review process. The CDP, once issued, will provide a 10-year authorization for Town-wide
maintenance dredging of navigational waterways and the beneficial reuse of sediments as
nourishment along various shoreline areas. Maintenance dredging of the Cotuit Entrance and
Embayment Channels and beneficial reuse of sediments as nourishment along Dead Neck are
included in the 10-Year CDP scope. However, due to the lengthy permitting timeline associated
with obtaining all required local, state and federal authorizations for a 10-year approval, the Town
is seeking separate regulatory approvals for the subject project so that maintenance dredging
and nourishment activities can be performed during the upcoming Fall 2023-Winter 2024.
As part of the pre-permitting efforts performed to date by the Town for the 10-year CDP,
sampling and analyses has been performed on representative sediment samples collected from
the Cotuit Bay Entrance and Embayment Channels and along Dead Neck. A final Suitability
Determination was issued by the USACE under NAE -2015-01632 on August 1, 2022 (See Exhibit
G, Table 1) which authorizes the beneficial reuse of sediments dredged from the Cotuit Entrance
and Embayment Channels along Dead Neck.
3. Dredge and Nourishment Site History
Table 2 below presents a historical summary of past dredging and nourishment activities that
have been authorized/conducted within the Cotuit Bay 8-foot Entrance and 10-foot Embayment
Channels and along Dead Neck based upon review of record plan and permit information found
to be available through requests made to the MA Department of Conservation & Recreation Office
of Waterways, MA Department of Environmental Protection (MA DEP) Chapter 91 Waterways and
NOTICE OF INTENT – MAY 2023 Foth · 6
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
401 Water Quality Certification Programs, and the US Army Corps of Engineers (USACE). Copies
of record documents obtained are provided in Exhibit F.
Review of record documents demonstrate that the Cotuit Bay Entrance and Embayment
Channels, along with other waterway areas including West Bay, North Bay and Seapuit River, have
been historically dredged to support and maintain safe navigation within the Three Bays
waterway system. Dredging of the existing Cotuit Bay Entrance and Embayment Channels were
most recently authorized in 1998/2001 and 2009. As a secondary benefit, sediments dredged
from these channels and others located throughout Three Bays have provided a suitable material
source for nourishing the barrier beach Dead Neck. Nourishing Dead Neck has been an on-going
process since the early 1980s, with a total of three major nourishment projects being authorized
in 1981, 1998/2001, 2009, and 2017. The aforementioned efforts consisted of placement of
±120,000 CY, ±250,000 CY, ±15,850, and ±160,000 CY, respectively, along Dead Neck starting at
the inlet/West Bay jetty and extending west up to a distance of 2,400 LF along the barrier beach.
These nourishment efforts have proven to be instrumental in stabilizing the barrier beach and
preventing breaching as well as enhancing beach and dune habitat for endangered shore bird
species that rely on Dead Neck.
Table 2: Prior Regulatory Authorizations Issued for Cotuit Bay Dredging & Nourishment at Dead Neck
YEAR PRIOR
AUTHORIZATION
NUMBER
AUTHORIZED
ENTITY
PRIOR
AUTHORIZED
DREDGE
EVENT
PRIOR
AUTHORIZED
DREDGE
SEDIMENT
REUSE/DISPOSAL
ESTIMATED
VOLUME
PURPOSE OF
DREDGE
SEDIMENT
REUSE
1934 DPW Contract
#397
Department of
Public Works -
Division of
Waterways
Upper Portion
of Embayment
Channel to
-6' MLW*
No Disposal Site
Identified
Info Not
Avail.
Info Not
Avail.
1954 DPW Contract
#1377
Department of
Public Works -
Division of
Waterways
Outer Portion
of Entrance
Channel*
to -8' MLW
No Disposal Site
Identified
Info Not
Avail.
Info Not
Avail.
1975** DPW Contract
#2799
Department of
Public Works -
Division of
Waterways
Cotuit Bay
Entrance
Channel*
No Disposal Site
Identified
Info Not
Avail.
Info Not
Avail.
1981 DPW Contract
#2974
Department of
Public Works -
Division of
Waterways
Cotuit Bay,
West Bay,
North Bay &
Seapuit River
Dead Neck
1,500 LF from
West Bay
Jetty/West *
±120,000
CY
To prevent
breaching
btw. West
Bay Jetty &
Dead Neck*
1998/
2001
CENAE-CO-R-
199701302;
MADEP Chapter
91 Permit #363;
MADEP Chapter
91 Permit #9123
Three Bays
Preservation, Inc.
Cotuit Bay 8'
Entrance
Channel & 10'
Embayment
Channel* (Note:
Cotuit Inner
Embayment,
West Bay &
Seapuit River
Channels also
included)
Dead Neck
2,400 LF from
West Bay
Jetty/West*
±225,000
CY
To prevent
breaching
btw. West
Bay Jetty &
Dead Neck;
Enhance
Dune/
Beach Areas*
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COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
2009 † NAE-2009-670
OOC Extension for
Wetlands File
#SE3-3743
Three Bays
Preservation, Inc.
Cotuit Bay 8'
Entrance
Channel, 10'
Embayment
Channel*, & 11'
Inner
Embayment
Channel
Dead Neck
500 LF from West
Bay Jetty/West*
±15,850
CY
To prevent
breaching
btw. West
Bay Jetty &
Dead Neck*
2017 NAE-2013-02073
MA DEP Chapter
91 Permit #14437
MA DEP 401 WQC
#X264968
Wetlands File
#SE-003-5053
Three Bays
Preservation, Inc.
and MA Audubon
Society
Cotuit Bay Cut
(3 Phases
conducted
2019 thru
2021)
Dead Neck
2,400 LF from
West Bay
Jetty/West*
±160,000
CY
To prevent
breaching
btw. West
Bay Jetty &
Dead Neck;
Enhance
Dune/
Beach Areas*
*PRIOR EVENTS SPECIFICALLY RELATED TO PROPOSED PROJECT
**DREDGE EVENT LISTED ON MA DCR OFFICE OF WATERWAYS RECORD INVENTORY. COPY OF CONTRACT PLAN NOT FOUND TO
BE AVAILABLE
† STATE AUTHORIZATION THROUGH MADEP CH91 WATERWAYS DREDGE PERMIT #9123 ISSUED 10/31/2001 & VALID THROUGH
10/31/2011
3.1 Alternatives Analysis
3.1.1 Dredging Alternatives
“No Dredge Alternative”
Under the “No Dredge” alternative, no dredging would occur within the Cotuit Bay Entrance and
Embayment Channels, thus promoting the continued deterioration of public access and safe
navigation within the waterway. Shoaling would continue to increase the potential for vessel
groundings, spills and/or release(s) of other hazardous materials into the Bay. The bottom
sediment would continue to be disrupted by vessels transiting over shoaled areas resulting in
resuspension of sediment to the water column. Accordingly, the “No Dredge” alternative is not
considered a viable option for the Town.
Maintenance Dredging
The preferred dredging alternative will restore navigation and public access to/from Cotuit Bay
and Nantucket Sound by maintaining the previously authorized depths and limits of the existing
Cotuit Bay Entrance and Embayment Channels. The current navigational depths and limits of
these channels adequately support vessel sizes and drafts, and therefore, the Town is not
seeking to widen or deep these channels.
3.1.2 Sediment Disposal Alternatives Analysis
Beach and Dune Nourishment
The USACE issued a Suitability Determination on August 1, 2022 under NAE-2015-01632 (see
Exhibit G), which authorized the placement of sediments dredged from the Cotuit Bay Entrance
and Embayment Channels onto Dead Neck Beach as nourishment. In accordance with MA DEP
Chapter 91 Waterways Regulations 310 CMR 9.40 (4)(a) clean dredged material shall be disposed
of in a manner that serves the purpose of beach nourishment. Utilizing dredged sediments for
nourishment is the preferred disposal alternative due to its’ cost effectiveness and inherent
environmental benefits, including but not limited to, restoration/enhancement of existing beach
and dune systems to provide habitat and protect surrounding areas from storm damage and
flooding. Additional economy will be recognized by the Town since the proposed project can be
performed by the Barnstable County Dredge Program which results in significant cost savings
over private contracting options. For the aforementioned reasons, no other disposal option is
being considered for the proposed project.
NOTICE OF INTENT – MAY 2023 Foth · 8
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
Dead Neck Beach is the preferred nourishment location as it is in immediate need of sediments
to address the recent breach that occurred in December 2022 and to restore/prevent further
erosion and impacts from loss of beach and dune resource areas. Below are several of the
factors which have contributed to the selection of Dead Neck as the preferred nourishment site:
· Sediments will be placed at a downdrift location of the dredge site and kept within the overall
littoral system;
· With respect to nesting habitat and protection, Dead Neck receives less human use than the
other sites considered; and
· Dead Neck Beach has been previously permitted/utilized for re-use of dredge sediment from
the Cotuit Bay Entrance and Embayment Channels.
3.2 Avalible Bathymetric and Topographic Information
Foth Infrastructure and Environment, LLC. (Foth) performed a hydrographic and topographic
survey within the Cotuit Bay Entrance and Embayment Channel and the westernmost tip of DNSI
– also known as Cotuit Cut – on March 18, 2022. A topographic survey was conducted by the
Town of Barnstable along the eastern end of Dead Neck, where the breach has occurred, on
March 23, 2023. This survey information has been utilized to establish existing bathymetric and
topographic conditions within Cotuit Bay and Dead Neck, identify wetland resource areas,
determine dredge quantities, and create a beach nourishment template for the proposed project.
The existing conditions are presented in the Permit Plans found in Exhibit E.
4. Suitability Determination (SD)
As part of the pre-permitting efforts performed to date by the Town for the 10-year CDP,
sampling and analyses has been performed on representative sediment samples collected from
the Cotuit Bay Entrance and Embayment Channels and along Dead Neck. Sediment sampling and
analyses associated were performed in two Phases; Phase 1 evaluated dredge sediments for
grain size distribution only and Phase 2 provided additional grain size and bulk chemical analyses
as deemed required by the USACE for determining suitability of sediment for reuse as
nourishment. A Phase 1 Suitability Determination (SD) was issued by the USACE under NAE -
2015-01632 on September 14, 2020. This SD was then amended for Phase 2 evaluations on
August 1, 2022. Both SDs are provided in Exhibit G and confirm that dredge sediments from the
Cotuit Entrance and Embayment Channel are suitable for beneficial reuse along Dead Neck..
5. Dredging & Disposal Operation
The Town’s objective for the proposed project is to secure all regulatory approvals required for
the dredging, dewatering and beneficial reuse of Cotuit Bay Entrance and Embayment Channel
sediments so that construction can occur during the upcoming Fall 2023-Winter 2024 dredge
season. Dredging will be performed using hydraulic methods for both the Entrance and
Embayment Channels. The hydraulic dredging option will consist of a suction-cutterhead that will
loosen the bottom sediments and entrain them as a sediment-water mix (e.g. “slurry”) so that
they can be pumped directly to a designated dewatering area at Dead Neck Beach and then
spread to the grades and slopes of the proposed nourishment template.
Dredging will be performed by the Barnstable County Dredge Program using the hydraulic cutter
suction dredge Sandshifter, a pushboat, and one or two support skiffs. A temporary pipeline will
be installed using HDPE flexible plastic pipe that extends from the dredge area at Cotuit Bay,
around the north side of DNSI and within the Seapuit River, to the nourishment site at Dead Neck
for a total length of approximately ±11,000 LF. A booster pump station will be required and placed
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in line with the dredge and slurry pipeline to ensure that sediments can be adequately pumped
the full distance to the nourishment site at the eastern-most end of Dead Neck.
Land based operations will be required for constructing a temporary dewatering containment
area where the dredge slurry (sediment plus seawater) will initially be received. Sediments will
naturally settle out of suspension via gravity and seawater (i.e. effluent) will percolate/return back
into the beach/Nantucket Sound thereby allowing for the placement and final grading of
dewatered sediments within the proposed nourishment template. The contractor will utilize an
excavator to trench an approximately 450-foot long by 60-foot wide dewatering area which will be
bound by the existing dune on the north side and a temporary low grade perimeter berm above
the MHW line to the south. The proposed dewatering operation is illustrated on the Permit Plans
provided in Exhibit E). As material is dried of excess water, a front end loader with rubber tires will
move sediment from the dewatering area to the nourishment area and spread to the grades and
slopes of the proposed nourishment template. Following the completion of nourishment
activities, all beach areas temporarily disturbed for sediment dewatering and equipment
use/access will be restored to preconstruction conditions.
6. Regulatory Approvals
6.1 General Overview
Based upon review of the collective site history and previously authorized work presented in
Table 2 (See Section 3, Dredge and Nourishment History), the activities to be authorized for the
proposed project are considered to be maintenance since all dredging and nourishment will be
performed within the previously established/authorized vertical and horizontal limits. A pre-
application meeting was held on April 14, 2023 to present and discuss the proposed project in
advance of commencing the regulatory agency review process. The meeting was organized by
the MA Office of Coastal Zone Management (MA CZM) and attended by representatives from the
Town, Foth, MA DEP, MA CZM, NHESP, MA Division of Marine Fisheries (MA DMF), National
Oceanic and Atmospheric Administration (NOAA) and U.S. Army Corps of Engineers (USACE). As
a result of pre-application discussions, an Environmental Notification Form (ENF) was submitted
to the MEPA Office in May 2023 to confirm that the proposed work is Routine Maintenance in
accordance 301 CMR 11.02. and as defined as follows:
Any maintenance work or activity carried out on a regular or periodic basis in a manner
that has no potential for Damage to the Environment or for which performance
standards have been developed that avoid, minimize or mitigate potential
environmental impacts to the maximum extent practicable.
The Secretary of Energy & Environmental Affairs (EEA) Certificate on the ENF is pending issuance
on June 9, 2023. In addition to the NOI being submitted herein, the following permits/approvals
are anticipated to be required for the proposed Cotuit Bay Entrance and Embayment Channel
Maintenance Dredging Project:
· NHESP MESA Determination (through Notice of Intent review process)
· MA DEP 401 Water Quality Certification
· MA DEP Chapter 91 Waterways Permit
· U.S. Army Corps of Engineers (USACE) Permit
· MA CZM Federal Consistency (through USACE review)
6.2 Additional Regulatory Requirements & Coordination
6.2.1 MA Chapter 91 Waterways
The proposed project will include the beneficial reuse of publicly dredge sediments on privately
owned lands at Dead Neck. In accordance with 310 CMR 9.40(4), a public access easement
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must be granted to the Town below MHW. The owner of Dead Neck, Three Bays Preservation,
Inc. (TBPI), is in full support of the proposed project and is working with the Town to develop the
public access agreement. Additionally, TBPI has provided a letter of support for the project, found
in Exhibit C. It is understood that fully executed agreement will be required to be in place for MA
DEP to issue the Chapter 91 Dredge Permit.
6.3 Post-Construction Monitoring Dead Neck-Sampson Island (DNSI)
As previously discussed in this narrative, nourishment activities were recently authorized and
completed along Dead Neck and Sampson Island as part of the Cotuit Cut–DNSI project. This
work was authorized by local, state and federal permits that were issued to TBPI. Approvals
issued require post-construction monitoring of nourishment and habitat restoration areas
associated with that project. All post-construction monitoring obligations will remain in full effect
for the durations specified by permits issued to TBPI. These obligations will be upheld by TBPI
and formalized in an agreement that will be executed with the Town as part of this project.
7. Performance Standards to Avoid, Minimize and Mitigation Impacts to Coastal
Resource Areas & Habitat
The proposed project is a water-dependent project that has been designed, and will be performed,
using the best available measures to minimize adverse impacts to coastal resource areas. The
following coastal wetland resource areas have been identified within the vicinity of the project
area as defined under the Massachusetts Wetland Protection Act (MA WPA) and per M.G.L. c.
131 sec 40 and Regulations 310 CMR 10.00: Land Under the Ocean (LUO), Land Containing
Shellfish (LCS), Coastal Beach, Barrier Beach, Coastal Dune, and Land Subject to Coastal Storm
Flowage (LSCSF). Coastal resources areas are delineated on the Permit Plans provided in Exhibit
E. It is noted that the project site is located entirely in Estimated Habitats of Rare Wildlife/Priority
Habitats of Rare Species as most recently mapped by the MA NHESP on August 1, 2021 (see
Exhibit H).
Pursuant to 310 CMR 10.00, the above listed coastal resource areas are to be regulated in order
to contribute to the following public interests:
· Flood control;
· Storm damage prevention; and/or
· Protection of marine fisheries and wildlife habitat.
The proposed project will restore and enhance safe public use and navigable access within the
Cotuit Bay/Nantucket Sound interface as required to continue to support commercial and
recreational uses. As a secondary benefit, dredge sediments will be beneficially reused along
Dead Neck thus restoring the barrier beach for sediment loss due to storm events and the natural
littoral drift of this system. Dead Neck provides important habitat for migratory birds and other
organisms, so erosion reduces the ability of the eastern portion of the island to maintain habitat
for animal nesting and foraging, as well as provide storm damage prevention for inland areas.
All work will be performed when marine activity is least active, within the established TOY
restrictions for all species of concern and conditions identified by permit authorizations issued
for the project . The paragraphs presented below provide the following information:
· Identification and definition of each coastal wetland resource areas to be
permanently or temporarily impacted by proposed activities;
· An assessment of the magnitude of anticipated impacts from proposed activities on
each coastal wetland resource area; and
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· Discussion on how proposed activities meets the performance standards for each
coastal wetland resource area impacted.
LAND UNDER THE OCEAN (310 CMR 10.25)
Land Under the Ocean (LUO) is defined as “land extending from the mean low water line seaward to
the boundary of the municipality’s jurisdiction and includes land under estuaries”. LUO, particularly
the nearshore area, is presumed significant to the protection of marine fisheries, protection of wildlife
habitat, storm damage prevention and flood control (310 CMR 10.25). Table 3 below presents a
summary of volumes removed and areas impacted from dredging within LUO. The limits of LUO
located within the project site are shown on the Permit Plans provided in Exhibit E.
Table 3: Summary of Impacts to Land Under Ocean (LUO) from Proposed Dredging of Cotuit Bay
Entrance and Embayment Channel and Nourishment Along Dead Neck
LOCATION
PROPOSED
WORK
PROP. DREDGE
DEPTH
(FT MLLW)
TOTAL VOLUME
REMOVED
FROM LUO (CY)
TOTAL LUO AREA
IMPACTED
(SF)
Cotuit Bay
Entrance
Channel
Maintenance
Dredging -8.0’ w/ 1’ O.D. 14,642 166,324
Cotuit Bay
Embayment
Channel
Maintenance
Dredging -10’ w/ 1’ O.D. 3,786 42,655
Total Dredge 18,428 208,979
Dead Neck
Beach Nourishment 0 0
*Dredge Area includes 3H:1V sideslopes
O.D. = Allowable Overdredge
Maintenance Dredging 10.25 (4): Maintenance dredging will be conducted to restore the navigable
conditions within the authorized limits of the Cotuit Bay Entrance and Embayment Channel.
According to 310 CMR 10.25 (4), “maintenance dredging for navigational purposes affecting land
under the ocean shall be designed and carried out using the best available measures so as to
minimize adverse effects on such interests caused by changes in productivity which will result from
the suspension or transport of pollutants, increase in turbidity, the smothering of bottom organisms,
the accumulation of pollutants by organisms, or the destruction of marine fisheries habitat or wildlife
habitat”. Marine productivity will not be adversely impacted by the proposed maintenance dredging
since operations will be conducted during the time of year when biological activity is least active and
in accordance with the TOY restrictions established by MA DMF. Short-term/minimal increases in
turbidity and suspended solids are expected to occur during the time of active dredging due to the
physical make up of sediments which is anticipated to consist of well-graded sand with gravel and
less than 5% fine content (see Exhibit G, Table 8 TBR-CB-1 and CB-2, Suitability Determination issued
September 14, 2020. Given the limited duration that it will take for the dredging to be completed, it is
expected that any increase in turbidity and suspended solids will be short in duration and temporary.
Accordingly, turbidity levels/impacts are expected to be limited and minimal. Dredging will also help
reduce turbidity over the long-term by minimizing the potential for vessel groundings and propeller
wash (or scouring).
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In accordance with 310 CMR 10.25 (6), the proposed project has been designed and will be constructed
using the best available measures so as to minimize adverse effects on marine fisheries habitat or
wildlife habitat as follows:
· Water Circulation: Water circulation is created by the tidal exchange and currents that exist within
Cotuit Bay and Nantucket Sound. Dredging is expected to improve the overall water circulation
through the increased tidal exchange that will occur through the removal of the shoals. The
proposed project is not expected to have any long-term negative effects on water circulation or
the overall hydrological or littoral processes.
· Destruction of Eelgrass or Widgeon Grass Beds: Based upon review of available MA GIS
information, eelgrass (Zostera marina) has been mapped by MA DEP in the vicinity of the Cotuit
Bay Entrance in 2001, 2010-13 and 2015-17. No dredging is proposed to occur within previously
mapped areas. Eelgrass was last mapped by MA DEP in 1995 offshore of the West Bay jetty and
inlet and approximately 330 feet (minimum) from the proposed nourishment area. Since 1995,
no other subsequent mapping of eelgrass has been identified; therefore, the proposed beneficial
reuse of dredge sediment for nourishment is not expected to result in impacts to eelgrass.
· Distribution of Sediment Grain Size: Dredging will not alter the sediment quality in the project
area. The sediments that will be removed by the proposed dredging have accumulated over time
from the dynamic natural littoral process and currents that exist within the harbor and Cape Cod
Bay.
· Water Quality: Short term increases in turbidity and suspended solids are expected to occur
during the time of active dredging. However, given the nature of the material anticipated to be
dredged from the navigation channel (i.e. sand and silty sand) and the limited duration of the
project, it is expected that the increases in turbidity and suspended solids will be short-term and
temporary. The daily tidal exchange will naturally help maintain water quality throughout
construction. Water quality is anticipated to improve following the completion of dredging since
there will be a reduction in potential for turbidity resulting from vessel/float groundings and
vessel propeller wash (or scouring).
· Shallow submerged lands with high densities of polychaetes, mollusks or macrophytic algae: The
project site is not known to support high densities of polychaetes, mollusks or macrophytic algae.
COASTAL BEACH (310 CMR 10.27)
Coastal Beach is unconsolidated sediment subject to wave, tidal and coastal storm action that forms
the gently sloping shore of a body of salt water and includes tidal flats (310 CMR 10.27). Coastal
Beaches extend from the MLW line landward to the dune line, coastal bank line or the seaward edge
of existing man-made structures, when these structures replace one of the above lines, whichever is
closest to the ocean. Coastal Beaches may play an important role in storm damage prevention, flood
control and the protection of marine fisheries similar to LUO. They may also be significant to the
protection of Land Containing Shellfish when shellfish are present. Coastal Beaches may reduce
wave energy, and natural beaches provide sediment to LUO, which serves as a buffer to storm waves.
Table 4 below presents a summary of volumes removed and areas impacted from dredging within
Coastal Beach. The limits of Coastal Beach located within the project site are shown on the Permit
Plans provided in Exhibit E.
MAINTENANCE DREDGING
All anticipated impacts resulting within Coastal Beach are anticipated to occur within the intertidal
zone (between MLW and MHW). Intertidal dredging is only proposed within the Entrance Channel
sideslope and is a result of in-filling that has occurred in the vicinity of the ever dynamic Cotuit Cut
area. To properly maintain the full limits of the authorized Cotuit Bay Entrance channel intertidal
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dredging is considered to be a necessary component associated with the periodic maintenance
required to sustain safe navigation and public use/access of the waterway.
BEACH NOURISHMENT
Dredge sediments removed from the Entrance and Embayment Channels will be utilized to restore the
existing, eroded and breached conditions along Coastal Beach areas at the eastern end of Dead
Neck. Dredge sediments have been found to be suitable for beneficial reuse as nourishment (see
Exhibit G, Suitability Determination)
Table 4: Summary of Impacts to Coastal Beach from Proposed Dredging of Cotuit Bay Entrance and
Embayment Channel and Nourishment Along Dead Neck
LOCATION
PROPOSED
WORK
PROP. DREDGE
DEPTH
(FT MLLW)
TOTAL VOLUME
COASTAL BEACH (CY)
TOTAL COASTAL
BEACH AREA
IMPACTED (SF)
Cotuit Bay
Entrance
Channel
Maintenance
Dredging -8.0’ w/ 1’ O.D. 221 1,571
Cotuit Bay
Embayment
Channel
Maintenance
Dredging -10’ w/ 1’ O.D. 0 0
Total Dredge 221 1,571
Dead Neck
Beach Nourishment 15,523 96,435
*Dredge Area includes 3H:1V sideslopes
O.D. = Allowable Overdredge
Temporary impacts to Coastal Beach will occur within the intertidal zone (between MLW and MHW)
where the hydraulic sediment slurry pipeline is proposed to come ashore at Dead Neck. Additionally,
land-based equipment required for placement and management of the pipeline will occur within
Coastal Beach. All temporary construction features and construction access will be returned to pre-
construction conditions when nourishment activities are completed. The temporary impact area
within the Coastal Beach is quantified as ±581 SF.
As described below, the Coastal Beach areas affected by the proposed maintenance dredging and
nourishment will not significantly alter the resource area’s ability to provide storm damage
prevention/protection, flood control or to protect marine fisheries or wildlife habitat:
Storm Damage/Flood Control
· Volume (Quantity of Sediments) and Form: The proposed dredging will increase flood storage
capacity. Re-use of dredge sediments for nourishment will provide storm damage/flood
protection along the existing coastal beach.
· Ability to Respond to Wave Action: Dredging will not result in a change in wave heights/velocities
impacting the shoreline or compromise the ability of the resource area to respond to wave action.
Nourishment will enhance the barrier beach’s ability to respond to wave action.
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Protection of Marine Fisheries or Wildlife Habitat
· Distribution of Grain Size: Dredging will not significantly alter the sediment quality within the
Cotuit Bay area. Sediments removed from the Entrance and Embayment Channels consist of
clean sand that will be placed along Dead Neck Beach as nourishment. Dredge sediments have
been determined to be compatible to existing beach sediments, thereby resulting in a stable
nourishment effort that will not alter the natural composition of the barrier beach system.
· Water Circulation: The proposed dredging will not impact water circulation, resulting in an
adverse change in flushing rate, temperature, or turbidity levels. The water circulation within the
project area is primarily a result of tidal flushing. The proposed dredging will not affect flushing
rates or temperature. Nourishment activities will not impact water circulation.
· Water Quality: Turbidity and the re-suspension of solids are anticipated to be minimal and
temporary due to the sediments consisting primarily of a well-graded sand with some gravel.
Hydraulic dredge methods will also help minimize the occurrence of turbidity, and water quality is
anticipated to improve following the completion of work since the potential for turbidity resulting
from vessel groundings and propeller wash (or scouring) will be reduced. Nourishment activities
may result in temporary/short-term turbidity during construction.
· Relief and Elevation: The proposed dredging will result in a minor modification along the
shoreline; however, it will also result in the significant reduction in the potential for vessel
groundings and propeller wash (or scouring). Nourishment will restore/enhance Coastal Beach
areas that have eroded and breached. Sediments will be placed along Dead Neck Beach at a
10H:1V slope, which will provide favorable conditions to support existing shorebird habitat as per
MA NHESP recommendations.
Storm Damage Prevention, Flood Control or Protection of Wildlife Habitat
· Increasing Erosion: Dredging will not result in a change in wave heights/velocities, and as such, it
will not increase erosion. Nourishment will restore the severely eroded area along Dead Neck
Beach and provide protection against storm damage and flooding. Sediments will be placed
along Long Beach at a 10H:1V slope, which will provide favorable conditions to support existing
shorebird habitat as per MA NHESP recommendations.
· Decreasing Volume: Dredging will not result in a significant volume loss within Coastal Beach.
Accordingly, the ability for Coastal Beach to provide storm damage, flood control or protection to
wildlife will virtually remain unaffected. Nourishment will result in an increase in volume to the
existing barrier beach and overall littoral system of Nantucket Sound/Cotuit Bay.
· Changing Form of Any Coastal Beach or an Adjacent or Downdrift Beach: Re-use of dredge
sediments for nourishment will immediately restore coastal beach areas and provide a sediment
source to downdrift beach areas over time.
COASTAL DUNE (310 CMR 10.28)
A Coastal Dune is defined under the MA Wetlands Protection Act as “any natural hill, mound or ridge
of sediment landward of a coastal beach deposited by wind action or storm overwash. Coastal Dune
also means sediment deposited by artificial means and serving the purpose of storm damage
prevention or flood control”. Table 5 below presents a summary of volumes removed and areas
impacted from dredging within Coastal Dune. The limits of Coastal Dune located within the project
site are shown on the Permit Plans provided in Exhibit E.
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Table 5: Summary of Impacts to Coastal Dune from Proposed Dredging of Cotuit Bay Entrance and
Embayment Channel and Nourishment at Dead Neck
LOCATION
PROPOSED
WORK
PROP. DREDGE
DEPTH
(FT MLLW)
TOTAL VOLUME
COASTAL DUNE (CY)
TOTAL COASTAL
DUNE AREA
IMPACTED (SF)
Cotuit Bay
Entrance
Channel
Maintenance
Dredging -8.0’ w/ 1’ O.D. 0 0
Cotuit Bay
Embayment
Channel
Maintenance
Dredging -10’ w/ 1’ O.D. 0 0
Total Dredge 0 0
Dead Neck
Beach Nourishment 3,126 31,697
*Dredge Area includes 3H:1V sideslopes
O.D. = Allowable Overdredge
Temporary impacts to Coastal Dune may occur where the hydraulic sediment slurry pipeline is
proposed to come ashore at Dead Neck, and where the proposed dewatering containment area will
be constructed. Earth moving equipment will be present in the Coastal Dune resource to place and
maintain the pipeline and construct/manage the temporary dewatering containment area. All
temporary construction features and construction access will be returned to pre-construction
conditions when nourishment activities are completed. The temporary impact area within the Coastal
Dune is quantified as ±74,531 SF.
The proposed nourishment will enhance the ability of the dune to erode in response to coastal
conditions. The dune volume will be restored/enhanced and the placement of dredge sediment for
nourishment will not restrict the ability of the dune form to move landward or laterally by wind and/or
natural water flow. The proposed nourishment template has been designed taking into consideration
recommendations provided by MA NHESP so that existing shorebird habitat is preserved.
BARRIER BEACH (310 CMR 10.29)
Barrier Beach means a narrow low-lying strip of land generally consisting of coastal beaches and
coastal dunes extending roughly parallel to the trend of the coast. It is separated from the mainland
by a narrow body of fresh, brackish or saline water or a marsh system. A barrier beach may be joined
to the mainland at one or both ends. 310 CMR 10.27(3) through (6) (coastal beaches) and 10.28(3)
through (5) (coastal dunes) shall apply to the coastal beaches and to all coastal dunes which make
up a barrier beach. Table 6 below presents a summary of volumes removed and areas impacted from
dredging within barrier beach. The limits of barrier beach located within the project site are shown on
the Permit Plans provided in Exhibit E.
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Table 6: Summary of Impacts to Barrier Beach from Proposed Dredging of Cotuit Bay Entrance and
Embayment Channel and Nourishment at Dead Neck
LOCATION
PROPOSED
WORK
PROP. DREDGE
DEPTH
(FT MLLW)
TOTAL VOLUME
BARRIER BEACH (CY)
TOTAL BARRIER
BEACH AREA
IMPACTED (SF)
Cotuit Bay
Entrance
Channel
Maintenance
Dredging -8.0’ w/ 1’ O.D. 221 1,571
Cotuit Bay
Embayment
Channel
Maintenance
Dredging -10’ w/ 1’ O.D. 0 0
Total Dredge 221 1,571
Dead Neck
Beach Nourishment 18,649 128,132
*Dredge Area includes 3H:1V sideslopes
O.D. = Allowable Overdredge
Temporary impacts to Barrier Beach may occur where the hydraulic sediment slurry pipeline is
proposed to come ashore onto Dead Neck, and where the proposed dewatering containment area be
constructed. Earth moving equipment will be present in the Barrier Beach resource area to place and
maintain the pipeline and dewatering area. All temporary construction features and construction
access will be returned to pre-construction conditions when nourishment activities are completed.
The temporary impact area within the Barrier Beach is quantified as ±75,112 SF.
LAND CONTAINING SHELLFISH (310 CMR 10.34)
Land Containing Shellfish (LCS) is defined as “land under the ocean…when any such land contains
shellfish”. Land Containing Shellfish shall be found significant when it has been identified and
mapped as follows: by the Conservation Commission or the Department in consultation with DMF
and based upon maps and designations of DMF; or by the Conservation Commission or the
Department based on maps and written documentation of the shellfish constable or the Department.
In making such identification and maps, the following factors shall be taken into account and
documented: the density of shellfish, the size of the area and the historical and current importance of
the area to recreational or commercial shellfishing.
According to the most current available MA GIS data pertaining to MA DMF mapped suitable shellfish
habitat, the proposed dredging within the Cotuit Bay Entrance and Embayment Channels and
nourishment activities at Dead Neck may be located within LCS. It is noted that areas mapped by MA
DMF include sites where shellfish have historically been sighted, but may not currently support any
shellfish. The shellfish suitability areas were not verified in the field and the boundaries were not
surveyed. Accordingly, this information should be used only as a guide to the approximate locations
of potential habitats. Areas of mapped LCS are currently designated as approved for shellfish
harvesting areas according to available data from MA GIS. Impacted areas of mapped LCS include
areas that have been previously authorized/dredged and nourished are considered to be Routine
Maintenance which occur periodically. Dredging within LCS is necessary to remove sediments that
have migrated into the established navigation areas primarily from sediment transport caused by
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storm events and currents in Cotuit Bay and Nantucket Sound. Accordingly, it is reasonable to
assume that LCS areas impacted by dredging will readily self-recolonize over time.
Details pertaining to the quantity and assessment of potential LCS impacts resulting from dredging
and nourishment activities are presented in Table 7 below. The limits of LCS located within the
project site are shown on the Permit Plans provided in Exhibit E.
Table 7: Summary of Impacts to Land Containing Shellfish (LCS) from Proposed Dredging of Cotuit
Bay Entrance and Embayment Channel and Nourishment at Dead Neck
LOCATION
PROPOSED
WORK
PROP. DREDGE
DEPTH
(FT MLLW)
TOTAL VOLUME
LCS (CY)
TOTAL LCS AREA
IMPACTED (SF)
Cotuit Bay
Entrance
Channel
Maintenance
Dredging -8.0’ w/ 1’ O.D. 0 0
Cotuit Bay
Embayment
Channel
Maintenance
Dredging -10’ w/ 1’ O.D. 311 4,379
Total Dredge 311 4,379
Dead Neck
Beach Nourishment 235 4,136
*Dredge Area includes 3H:1V sideslopes
O.D. = Allowable Overdredge
PRIORITY/ESTIMATED HABITAT
The proposed dredge and nourishment areas are entirely located within Estimated Habitat of
Rare Wildlife and Priority Habitat for Rare Species, as designated by the latest map revisions
issued by the Massachusetts Natural Heritage and Endangered Species Program (NHESP) in
August 2015. Habitat maps are provided in Exhibit H. Piping Plover and Least Tern have been
identified by MA NHESP as protected bird species known to nest along Dead Neck Beach. The
proposed project is not anticipated to impact plover or tern habitat as the proposed
dredging/nourishment activities will occur outside of the breeding season which typically occurs
between April 1st – August 31st. The nourishment template has been designed to incorporate
recommendations as provided by MA NHESP such that existing nesting, feeding or chick-rearing
habitat is not adversely impacted by the placement of dredge material along Long Beach,
including maintaining no steeper than a 10H:1V slope.
Temporary impacts to NHESP may occur where the hydraulic sediment slurry pipeline is
proposed to land at Dead Neck, and where the proposed dewatering area will be located . Earth
moving equipment will be present in the NHESP resource area to place and maintain the pipeline
and dewatering area. All temporary construction features and construction access will be
returned to pre-construction conditions when nourishment activities are completed. The
temporary impact area within the NHESP mapped area is quantified as ±75,112 SF.
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Table 8: Summary of Impacts to NHESP Priority/Estimated Habitat from Proposed Dredging of
Cotuit Bay Entrance and Embayment Channel and Nourishment at Dead Neck
LOCATION
PROPOSED
WORK
PROP. DREDGE
DEPTH
(FT MLLW)
TOTAL VOLUME
NHESP (CY)
TOTAL NHESP AREA
IMPACTED (SF)
Cotuit Bay
Entrance
Channel
Maintenance
Dredging -8.0’ w/ 1’ O.D. 14,863 167,895
Cotuit Bay
Embayment
Channel
Maintenance
Dredging -10’ w/ 1’ O.D. 3,786 42,655
Total Dredge 18,649 210,550
Dead Neck
Beach Nourishment 18,649 128,132
*Dredge Area includes 3H:1V sideslopes
O.D. = Allowable Overdredge
LAND SUBJECT TO COASTAL STORM FLOWAGE (310 CMR 10.57)
Subject to Coastal Storm Flowage (LSCSF) means land subject to any inundation caused by coastal
storms up to and including that caused by the 100-year storm, surge of record or storm of record,
whichever is greater (310 CMR 10.57). The areas mapped by the Federal Emergency Management
Agency (FEMA) on community Flood Insurance Rate Maps (FIRM) as the 100-year flood plain within
the coastal zone are included within LSCSF. Land Subject to Coastal Storm Flowage may be
significant to the interests of storm damage prevention, flood control, pollution prevention and
wildlife habitat.
Of the proposed nourishment at Dead Neck, 41,353 SF is located within LSCSF. LSCSF in this
area contains other jurisdictional resource areas, including Barrier Beach, Coastal Dune, and
Coastal Beach, which are important for storm damage prevention and flood control. There are
currently no performance standards for work in LSCSF. The proposed nourishment will greatly
benefit LSCSF by enhancing the ability of the barrier beach to prevent/minimize storm and flood
damage.
Temporary impacts to LSCSF within the temporary construction and dewatering amount to
75,112 SF. All proposed temporary work will be above the MHW line. All temporary construction
features and construction access will be returned to pre-construction conditions when
nourishment activities are completed.
7.1 Minimization of Impacts
The proposed project has been designed to minimize the impacts to the existing coastal resource
areas and habitats to the greatest extent possible. All dredging and nourishment activities will be
performed during the TOY established by permits. Although a “No Dredge” alternative would result
in no environmental impacts, there is a potential for environmental impacts resulting from vessel
ground-outs along the shoaled in areas present Cotuit Bay Entrance and Embayment Channels.
Not only do vessel ground-outs present the potential for oil spills or release of other hazardous
materials into the harbor, they result in an increase of turbidity within the water column from the
resuspension of sediments. Furthermore, a “No Dredge” alternative presents a public safety
NOTICE OF INTENT – MAY 2023 Foth · 19
COTUIT BAY ENTRANCE AND EMBAYMENT CHANNEL MAINTENANCE DREDGING PROJECT
TOWN OF BARNSTABLE DEPARTMENT OF PUBLIC WORKS
concern and diminishes public access to the waterfront. Nourishment performed within coastal
resource areas/habitats will restore and enhance the Dead Neck barrier beach system. Dead Neck
provides important habitat for migratory birds and other organisms and provide storm damage
protection for inland areas.
8. Summary
The Town of Barnstable is proposing to perform maintenance dredging within the existing Cotuit
Bay Entrance and Embayment Channels. Dredging is required to address shoaling, restore
navigation and safe public access and use of the waterway. The proposed maintenance project
will consist of dredging a total combined area of ±210,550 square feet (SF) (±4.83 Ac) and an
estimated ±18,649 CY of sediment, including 3H:1V sideslopes and a 1-foot allowable
overdredge. The Cotuit Bay Entrance Channel will be restored to its’ previously authorized
footprint to -8.0 feet Mean Lower Low Water (MLLW) with a one (1) foot allowable overdredge to
-9.0 feet MLLW and approximate 3H:1V sideslopes. The Cotuit Bay Embayment Channel will also
be restored to its’ previously authorized footprint to -10.0 feet MLLW with one (1) foot allowable
overdredge to -11.0 feet MLLW and 3H:1V sideslopes.
As a secondary benefit to this project, dredge sediments will be beneficially reused along the
eastern-most end of Dead Neck to address a recent breach at the West Bay jetty and shoreline
erosion along approximately ±800 LF of barrier beach. Sediments will be placed along Dead
Neck to within previously authorized elevations and slopes, with the crest of the berm tying into
existing dune elevations. All slopes along the foreshore beach will be graded to 10H:1V to
accommodate shorebird nesting habitat with the toe ending at Mean Low Water (MLW).
The Town is seeking to obtain all regulatory approvals in time for dredging to be performed
during the Fall 2023-Winter 2024 season. The proposed project has been designed so that all
impacts have been minimized to the greatest extend feasible.