Harbor - Little
Mussachuck - Sachuest
Sachuest Salt Marsh Restoration,
History | Planning
| Construction | Monitoring
| Lessons Learned
Site Description and
The Sachuest Salt Marsh is located within the Sachuest National
Wildlife Refuge in Middletown, Rhode Island. The marsh is now
about 45 acres in extent, although it was originally part of a
much larger salt marsh complex in the southeastern part of Aquidneck
|View of creek in Sachuest marsh
Courtesy: National Marine Fisheries Service
Beginning in the late 19th century and continuing
through the mid-20th century, the area was subject to a number
of significant alterations that destroyed most of the marsh complex
and led to the severe degradation of the wetlands that remained.
A large reservoir, Gardiner Pond, was built on the marshes, probably
in the early 1900s. During the World War II era and later, Sachuest
Point was used as a military installation. A municipal dump was
operated on the Point, using the surface of the marsh itself as
a dumping area, and later closed. Parking lots were developed
for two municipal beaches adjacent to the marsh, Second and Third
Beach. In the late 20th century, Sachuest Point, including the
salt marsh, was designated a National Wildlife Refuge. Like all
such refuges, the area is now managed by the U.S. Fish and Wildlife
Salt marshes require frequent tidal flushing in
order to maintain their unique biological characteristics. The
Sachuest Salt Marsh is connected to the Sakonnet River, the eastern
arm of Narragansett Bay, by way of tidal creek that crosses Third
Beach. About 50 years ago, a road was built through the marsh,
perpendicular to the tidal creek. A concrete pipe beneath the
road was intended to allow the tide to continue to enter the marsh;
but the pipe was badly undersized, and the tide was unable to
flood the western half of the marsh. Salinity was reduced and,
over a period of years, the invasive reed Phragmites
came to dominate the restricted part of the marsh.
In 1989, the oil tanker World
Prodigy ran aground on Brenton Reef, off Newport, Rhode Island
- not far from the Sachuest Salt Marsh. The ship spilled nearly
300,000 gallons of home heating oil, killing fish, lobsters and
shellfish in Narragansett Bay and Rhode Island Sound. Under federal
law, the state and federal governments have the right to sue shipowners
and other parties responsible for oil spills, and to use the proceeds
to restore natural resources. With funding from the World Prodigy
settlement, the National Oceanic and Atmospheric Administration
(NOAA) identified the Sachuest Salt Marsh as a restoration opportunity,
and funded planning and construction of the project. A number
of partner organizations provided essential support and expertise
to make the project a reality, including the Town of Middletown,
the R.I. Department of Environmental Management, U.S. Fish and
Wildlife Service, U.S. Geological Survey (USGS), University of
Rhode Island (URI), and U.S. Army Corps of Engineers.
Planning for the project consisted of three major
- A site investigation by the Corps and others that produced
a technical report which recommended an approach to restoration
of the site (Corps undated).
- An environmental assessment (NOAA 1996), required of federal
projects, that evaluated the project overall to establish that
it would be practicable and beneficial, and to serve as the basis
for environmental permitting.
- A baseline ecological study by USGS and URI, which surveyed
existing conditions in both restricted and unrestricted areas
of the marsh, recording the flora and fauna present (Roman et
al. 1997) and serving as the basis for subsequent monitoring efforts.
|Replacing culverts beneath the road through
After all the planning work that went into the Sachuest
Salt Marsh restoration, construction was almost anticlimactic.
Over the course of just a few days in March, 1998, a construction
crew from the Middletown Department of Public Works replaced the
concrete pipe beneath the road with a set of larger culverts to
allow the tide to flood the marsh again. Special wide-tread excavators,
designed to work on wetlands, were used to re-open channels that
had filled with silt and Phragmites. The Rhode Island
Mosquito Abatement Coordination Program designed and constructed
an "open marsh water management" project which reduced
breeding opportunities for mosquitos by increasing tidal flushing
of depressions on the marsh surface and improving habitat for
fish that prey on mosquito larvae, like mummichogs
The USGS and URI group that undertook the baseline ecological
study of the marsh was also responsible for monitoring the restoration.
In 1998 and 1999, the group again sampled plants, fish, and shellfish
in the part of the marsh that had been tidally restricted as well
as the unimpacted area, using a variety of statistical methods
to compare the plant and animal communities in both parts of the
marsh. The design of the monitoring effort, comparing the restricted
and unrestricted areas of the marsh before and after the restoration,
provided the opportunity for rigorous scientific assessment of
the success of the project.
Researches from URI found that the western side
of the marsh had responded well to restoration. Phragmites
and cattail, another brackish-water plant, decreased significantly
following the restoration, while typical salt marsh species such
hay grass (Spartina patens) and smooth
cordgrass (Spartina alterniflora) increased. After
two years, the vegetation in the formerly restricted area was
still quite different from that in the unimpacted area, but seemed
to be on a trajectory toward a typical salt marsh plant community.
As would be expected, fauna were found to respond
more quickly to the restoration. Just one year after the restoration,
fish and crustaceans were as abundant and diverse in the formerly
restricted part of the marsh as in the unimpacted area. The most
common species was the mummichog,
but nearly twenty species were observed, including several other
species of marsh minnows, blue
crab, black sea bass, American
eel, and two species of shrimp (Roman et al. in press).
|New culverts allowing tidal flow into the
restored section of marsh
The experience of the Sachuest Salt Marsh restoration
was consistent with results from similar projects throughout the
coastal United States, adding to a growing body of data about
tidal marsh response to restoration. Marsh flora and fauna both
responded strongly to the restoration by becoming more like the
biological communities present in unimpacted marshes. Fish and
crustaceans responded quickly to the restoration, as their mobility
allows them to take immediate advantage of newly created habitats.
Plants responded more slowly, but seem to be moving toward the
type of vegetative community that would be present in an unrestricted
marsh. Several recent studies of restored New England marshes
have shown that it may take several decades for salt marsh vegetation
to become fully established in the formerly restricted part of
the Sachuest Salt Marsh.
NOAA, 1996. Final M/V World Prodigy Oil Spill Restoration
Plan and Environmental Assessment Narragansett Bay, Rhode Island.
Roman, C.T., K.B. Raposa, S.C. Adamowicz, M.J. James-Pirri,
and J.G. Catena. In press. Quantifying vegetation and nekton response
to tidal restoration of a New England salt marsh. Restoration
Roman, C.T., C.L. LaBash, K. Raposa and G. MacPhee.
1997. Restoration of the Sachuest Salt Marsh (Middletown, R.I.):
Pre-Restoration Ecological Baseline Information. Unpublished Report.
National Marine Fisheries Service, Gloucester, Massachusetts.
U.S. Army Corps of Engineers. Undated. Biological
and hydrological evaluation of the Sachuest Point Salt Marsh,
Middletown, R.I. Unpublished report. U.S. Army Corps of Engineers,
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