Marsh restoration project launches
The town’s iconic salt marsh – better known as Great Creek – is bounded by North Road on the west, Conanicut Island Sanctuary and the Jamestown Golf Course to the south, Windmist Farm to the north, and Route 138 to the east.
The scenic marsh is a popular spot for shellfishing, and a favorite subject for Jamestown’s painters and photographers. A diverse mix of native and migrating birds depend on the marsh for food and habitat. It also serves as a nursery to a vast array of aquatic creatures that form the base of our local food web.
In fact, tidal marshes like Round Marsh are among the most productive ecosystems on Earth, equaled only by tropical rainforests.
Unfortunately, invasive plant species, and the restricted flow of saltwater, have compromised the health of the marsh, and the important habitat it provides. Like many marshes statewide, sections of Round Marsh are sinking, slowly decaying and being overrun by tall marsh reed called phragmites australis. Sea-level rise also contributes to these trends.
Now, after years of planning, the Jamestown Conservation Commission is launching a restoration and adaptation project designed to increase the flow of saltwater and eradicate the invasive vegetation. The end result: restored plant and wildlife habitat, and increased resilience of the marsh.
The invasive plant phragmites has been expanding in recent years at the far eastern section of Round Marsh. Additionally, trapped standing water on the upper marsh areas in the northeastern, eastern and southeastern sections of Round Marsh has resulted in bare areas with no vegetation, degraded peat conditions, and increased mosquito breeding.
Without salt marsh plants to trap sediment and build organic material from the marsh grass itself, the elevation has not kept up with higher sea levels in recent years.
Key restoration work will include excavating the creeks to restore saltwater flow, and cutting and mulching the invasive phragmites. Excavation and cutting work will begin as soon as this week, weather permitting, and is expected to take less than two weeks.
Excavation will make use of specialized construction equipment, including an odd-looking machine called a marsh walker. The low ground-pressure vehicle, which looks like a traditional Bobcat with extra wide tracks to disperse its weight, is designed for use in sensitive areas where traditional equipment would damage vegetation.
Several collaborators with marsh restoration expertise will support the town to meet the project goals. Project partners include the state’s Coastal Resource Management Council, the Rhode Island Department of Environmental Management, the U.S. Natural Resources Conservation Service, the Audubon Society of Rhode Island, and Save The Bay.
Jamestown public works staff will operate the equipment under the direction of Town Engineer Michael Gray and Alan Gettman, DEM’s mosquito abatement coordinator. In areas not suitable for the low-pressure equipment, the Conservation Commission and Save The Bay will coordinate volunteer “dig days.” Participants will excavate the creeks with shovels. All of the excavated material from the various channels and ditches will be transferred to low areas on the marsh surfaces that are either not vegetated or have standing water.
The Neale family of Windmist Farm is also supporting the effort, providing construction and equipment access to the marsh from their upland fields that border the marsh to the north.
The Round Marsh restoration project is designed to reduce the amount of trapped water on the marsh surface, which will allow native salt marsh grasses to recolonize. Work will also condense the habitat for mosquito breeding, and at the same time, reduce the amount of phragmites australis that has crowded out native plants and minimized habitat for native species.
Adaptive management measures are designed to restore tidal exchange and to promote drainage of impounded water areas. Adaptation activities at Round Marsh will allow re-establishment of salt marsh vegetation. Additionally, freshwater trapped on the marsh surface will be able to drain and prevent the continued expansion of phragmites australis. This will strengthen the marsh’s natural coastal protection function during extreme weather, and will increase its resilience to sea-level rise.
The project has been years in the making, dating back to 2007 when the Conservation Commission initiated project planning, spearheaded by former Chairwoman Carol Lynn Trocki.
In the summers of 2012 and 2013, Save The Bay’s restoration coordinator, Wenley Ferguson, and her staff performed detailed assessments of Round Marsh and documented the conversion of marsh to barren, ponded water areas that are becoming common to salt marshes across Rhode Island. Upper marsh areas are converting to bare areas with shallow, ponded water, compromising the health of the marsh.
To fund the Round Marsh adaptation and restoration project, the Jamestown Conservation Commission secured competitive grants from the Natural Resources Conservation Service, as well as the CRMC’s trust fund for coastal and estuary habitat restoration.
The CRMC, Army Corp of Engineers and Department of Environmental Management recently approved the restoration plans and granted permits, allowing the project to move forward.
Project work will be visible from North Road at Great Creek, as well as from the viewing platforms at the Conanicut Island Sanctuary. A detailed description of the project plan, and a map of the restoration activities, are available on the town’s website.
Editor’s note: The author is a member of the Jamestown Conservation Commission.