SUFFOLK COUNTY – GOLDSMITH INLET -- CAPITAL PROJECT
Introduction
Goldsmith Inlet was once a vibrant and healthy ecosystem supporting a wide range
of wildlife, shellfish, boating, swimming and fishing in a safe and healthy
environment – a recreational gem on the North Fork. Unfortunately its health has
been rapidly declining as pollution levels have increased to dangerous levels.
The Inlet is located at the western end of the globally rare “maritime freshwater
interdunal swale” on the north shore of Long Island in the Town of Southold,
stretching from Goldsmith Inlet to Horton Point on the Eastern end. It is on the
Significant Habitat maps issued by the NY Department of State and its
preservation is included in the Town of Southold Local Waterfront Revitalization
Program (LWRP) – Reach 2. The Inlet is also on the NYSDEC Priority Water
Problem List with a ranking of severe.
Site Description: Goldsmith’s Inlet (inlet) is an approximately 20 acre tidal
impoundment with water flowing into the inlet;
a) through a series of drainage culverts that link the Inlet to a series of nearby
ponds and topographic depressions,
b) as sheet flow from adjacent upland areas, and
c) from Long Island Sound (LIS) through a tidal channel.
Due to the sandy nature of nearby soils, the inlet likely also receives a significant
quantity of groundwater discharge. Water leaves the inlet through the tidal channel
during low tide. In its present configuration, one jetty extends approximately 300
feet into LIS on the west side of the channel outlet.
Historically, two jettys, visible on aerial photographs dated 1957 extended
approximately 100 feet into LIS on either side of the channel. These were
comprised of woody materials and were allowed to deteriorate.
Problem Definition: The ecological health of the inlet has been compromised by
sedimentation related to the present hydraulic configuration of the tidal channel
that links the inlet to LIS. This increased sedimentation is accompanied by reduced
flushing rates (i.e. less turnover or replacement of inlet waters), a condition that
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typically results in decreased water quality and degradation of benthic invertebrate
communities that comprise much of the foundation of the aquatic food chain.
Reduced flushing has been responsible for elevated pathogen concentrations that
have been observed within the inlet reported by the New York State Department of
Environmental Conservation in 2009.
Historical modifications to the tidal channel outlet appear to have significantly
modified beach morphology near the tidal channel leading to the inlet. In the early
1900’s two jetties were extended from either side of the inlet into LIS. Subsequent
to the construction of the 2 jettys, the western jetty was extended to its current
length of approximately 300 feet and reinforced while the eastern jetty was
allowed to degrade. Sand, carried by the east-bound currents in LIS caused beach
accretion to the west of the present jetty. Sand and other sediment suspended in the
west-bound currents is currently funneled into the inlet.
Understanding the Cause: Sediment deposition rates and patterns are intimately
related to flow velocity. Carrying capacity is the technical term used to describe
the amount of sediment that can be carried by water moving at a particular
velocity. At lower velocities, suspended particles begin to drop out and settle.
Artificial structures, such as jetties, alter water velocities (both magnitude and
direction) and thus change depositional patterns. Over time, and without additional
structural changes, sediment zones reach a steady state where particles are
deposited and re-suspended at the same rate.
Limited dredging has been completed in the entrance channel to the inlet from the
LIS (i.e. steady state has not been allowed to occur) and there is a net inflow of
sediment into the inlet from LIS. The remaining jetty at the western side of the
inlet directs incoming tidal waters, and any sediment carried by them into the inlet.
As this flow moves through the narrow portion of the tidal channel, the magnitude
of the velocity is sufficient to carry sediment farther into the inlet. A sandbar has
formed where the channel cross section widens, a condition that reduces the flow
velocity leading to the sediment load carried by it to drop. It is to be determined
whether growth of the sandbar has occurred at a steady rate with each incoming
tide, or if most sandbar growth occurs during “nor’easters” which bring extensive
sand loads into the inlet. Local observations suggest the latter may be the primary
cause.
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Attempts to Remedy: A major dredge of the channel into the Inlet was conducted
in 2003. It was ineffective as all of the dredged sand returned within a few months.
Also, the newly opened channel temporarily allowed large amounts of additional
sand to be deposited further back into the Inlet. The Town of Southold is now
required to conduct annual emergency dredging at the entrance from LIS to
maintain a small amount of tidal flow.
WORK PLAN
A comprehensive analysis of the cause(s) of the significant accretion of sand into
the Inlet, its impact on the reduced rate of tidal flow and the resulting high levels of
pollution is required to determine appropriate long term corrective actions.
The Work Plan will be prepared by combining existing information with new data
to be generated through a series of targeted studies. The end products will provide
the detail scientific, fact based data required to begin implementation of the
recommended Action Plans.
The overall Work Plan for Goldsmith Inlet will consist of 5 main Tasks as follows:
1. Flushing Rate Analysis,
2. Watershed Drainage Analysis and Sediment Loads
3. Coastal Sediment Management
4. Community Input and Education,
5. Recommendations and Action Plans
Task 1. Flushing Rate Analysis. The rate of flushing of the Inlet is an important
factor in the management of Inlet water quality. Sand and silt has settled within the
Inlet decreasing the amount of flushing to Long Island Sound. The accretion of
sand has accelerated since the gradual loss of the eastern jetty, and the rebuilding
of only the Western jetty, at the mouth of the channel. The reduced flushing serves
to decrease the water quality of the Inlet since pollutants resulting from storm
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water runoff, septic systems and wildlife are less effectively diluted and flushed
out. To date the rate of flushing in the southern area of the Inlet is unknown. This
task will determine areas within the Inlet that are subject to restricted tidal flow by
conducting a tidal prism study. Automated water level logging devices
(leveloggers) will be deployed to determine if and where restrictions occur. If the
channel is restricting flow, leveloggers located within the Inlet will demonstrate
decreased tidal amplitude and/or have a different temporal pattern of high levels
(associated with high tides). The leveloggers will also measure additional
parameters such as temperature and salinity. The information will then be used to
help assess flushing issues and examine the impacts of rainfall events on the Inlet.
Salinity data will be used to determine the spatial trend of the invasive species
common reed (phragmite australis). There will be approximately four (4) stations
deployed for several months. All data (water level, temperature, salinity) will be
logged, periodically downloaded and compiled in a report . This will then be input
for recommendations to restore adequate tidal flow/flushing to the Inlet.
Task 2. Watershed Drainage Analysis and Sediment Loads. The recent influx of
sediment in the upper reaches of Goldsmith Inlet be conveyed from the upland by
way of positive drainage systems. The watershed and drainage infrastructure will
be mapped, in addition to land use. This information will be used to formulate
recommendations to drainage facilities to reduce the sediment loads to the inlet.
Task 3. Coastal Sediment Management. The flux of coastal sediments into
Goldsmith Inlet greatly influences water quality, and a plan to properly manage
this sediment loading is desired. Over the past two decades, plans to shorten the
jetty have been accompanied by numerous studies of the resulting impacts. The
Work Plan will review existing data and practices, and also collect additional
bathymetric surveys for use in this effort. It must be acknowledged, that in the case
of tidal inlets, periodic maintenance, on the order of annually or biennially, will
likely be the key to any workable solution. The coastal sediment component of the
Work Plan will include a review of existing information and analysis of newly
collected data
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Task 4. Community Input and Education. This Task will gather data
(historical data, photographs, prior reports/analysis, etc.) from long-time local
residents and Southold Town representatives. Education will also be provided to
help assure that local citizens and government departments implement eco-healthy
processes and procedures to assure the future long term health and safety of the
Inlet.
Task 5. Recommendations and Action Plans. The data collected from the Tasks
above will be analyzed and recommendations for the steps necessary to reverse the
serious environmental degradation of the Inlet will be provided. These
recommended Action Plans will define the specific action steps, timeframes, costs
and benefits for the design and construction of a long term solution to restore the
health and safety of Goldsmith Inlet.
Lead Agency – The Suffolk County Department of Public Works will be the lead
agency.
Project Manager – To Be Determined. (The Group For The East End (GFEE) is
available to provide overall coordination and project management, as previously
defined in the original ¼% Grant request).
Sole Source Provider Recommendation – The Cornell Cooperative Extension
Service and eDesignDynamics, Inc. are recommended as sole source providers for
this project, based on their specific work experience on prior water flow and water
quality projects at Goldsmith Inlet.
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COMMUNITY SUPPORT
The Town of Southold - recognizing the serious degradation and rising pollution
levels in Goldsmith Inlet, and desiring a long term solution to the increasing
amounts of sand that are infilling the Inlet, developed the Goldsmith Inlet
Management Plan encompassing all aspects of restoring the Inlet. The
Management Plan, approved by the Town Board in 2009, was developed in close
coordination with local citizen groups.
The Group To Save Goldsmith Inlet (GSGI) - is a citizen based organization
committed to restoring the health and safety of Goldsmith Inlet. GSGI volunteers
will actively participate and support the Work Plan defined above to help assure its
success.
Since its inception in 1998 the GSGI has developed a broad base of support with
other environmental organizations including The Group For The East End, The
Peconic Land Trust, the North Fork Environmental Council, and the North Fork
Audubon Society.
The GSGI conducts numerous volunteer activities addressing the health and safety
of the Goldsmith Inlet watershed (the Inlet, Autumn Pond, County Park, Town
Beach and surrounding geographic area). These include providing environmental
tips for the health of the Inlet to more than 2000 homeowners, initiating a
Watershed Watch to ensure environmentally sound activities in the area (supported
by the local and DEC police), and Clean-Up projects that have removed more than
80 tons of debris from the ecosystem.
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COST ESTIMATE
Task 1 - Flushing Rate Analysis
$15,000.00
Task 2 - Watershed Drainage Analysis
$5,000.00
Task 3 - Coastal Sediment Management
$28,000.00
Task 4 – Community Input and Education
$4,000.00
Task 5 – Recommendations and Action Plans
$20,000.00
Contingency
$5,000.00
Project Management
$8,688.00
TOTAL:
2/11/2011
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$85,668.00