The U.S. Fish and Wildlife Service and The Nature Conservancy are working to restore and strengthen salt marsh habitat at Sachuest Point National Wildlife Refuge to better withstand impacts of sea-level rise and coastal storm surge.
The project focuses on the Maidford River marshlands, adjacent to Third Beach.
The work is part of a $1.98 million cooperative agreement between The Nature Conservancy and the U.S. Fish and Wildlife Service, supported by federal funding for Hurricane Sandy recovery.
It is also part of a larger $4.1 million Sandy-funded effort to restore coastal areas from Rhode Island to Southern Maine.
Jennifer White, Service wildlife biologist and coordinator for the restoration project, said that the Service and TNC will begin work next year to address similar marsh restoration issues involving the Narrow River at the John H. Chafee National Wildlife Refuge in Narragansett.
White said storm surge and wave erosion, combined with the lack of replenishment from estuaries whose rivers have been dammed or choked off by centuries of development, have left once-hardy tidal marsh ecosystems at a point where saltmarsh elevations cannot keep up with sea-level rise.
Sachuest Point, the section of the marsh behind Third Beach, is too low to drain properly at low tide, leaving it particularly vulnerable to heavy flooding during storm surges. These prolonged periods of inundation impede the growth of high-marsh vegetation and impact healthy fish and wildlife habitats.
Healthy saltmarsh is sometimes able to retreat slowly over time, colonizing adjacent areas as sea level rises. At Sachuest Point, however, the marsh is constrained by Third Beach to the north and upland areas to the east and south.
With little opportunity for migration, the best solution to protect Sachuest Point wetlands is to raise the elevation of the marsh itself.
To do that, the Service and the Conservancy are applying a technique called “thin-layer deposition” (TLD), where sand is strategically spread onto areas of the marsh that are too low.
This technique, combined with high-pressure spray dredging, has been successfully used in coastal areas in Delaware, Maryland and New York to restore marshes adversely affected by accelerated sea-level rise.