Restoring and enhancing

The above map shows restoration and enhancement areas for dredging in Narrow River.

NARRAGANSETT - In late October, The U.S. Fish and Wildlife Service and The Nature Conservancy announced a project with the Coastal Resources Management Council that will restore and strengthen the saltmarsh habitat at the John H. Chafee National Wildlife Refuge.

The initiative focuses on the 30 acres of marsh on the eastern shore of the Narrow River estuary and aims to enhance wildlife habitat while combatting the looming threat of sea level rise. The project will dredge the floor of the river, then place the dredged material on the surface of the marsh, so as to elevate the land and allow plants to thrive.

According to a press release issued by the Coastal Resources Management Council last week, Narrow River is currently experiencing problems related to an abundance of surface water in the marsh, thought to be due to sea level rise. The issue arises when plant life and other habitats are suppressed due to the constant presence of surface water.

“There are currently many areas of the marsh where ponded water stays on the surface, even at low tide, drowning vegetation and providing areas for mosquitos to breed,” the release reads. “This is thought to be the result of sea level rise, which is happening at an increasingly faster rate due to climate change.”

According to the Rhode Island Sea Grant, sea level in Rhode Island is projected to increase by 3 to 5 feet above 1990 levels by 2100, and a potential for a one-foot rise by 2050. The effects of such a phenomenon could be extensive if preventative measures are not taken.

“Marshes with healthy vegetation are better able to accumulate sediments and build elevation to keep up with rising sea levels,” the release continues. “However, recent evidence suggests that most of the marshes in Rhode Island are not keeping pace with sea level rise and drowning. If the marsh disappears, the important ‘ecological services’ it provides will be lost. Among many other functions, marshes are important habitat for fish and wildlife.”

The project on Narrow River is being funded by a $1.4 million cooperative agreement between The Nature Conservancy and the U.S. Fish and Wildlife Service, using monies allocated for relief in the wake of Superstorm Sandy. In early November, dredging crews started mobilizing at the Chafee Refuge and began dredging in designated areas from Middlebridge to Sedge Island.

“The dredged material will be placed on the existing salt marsh and then spread across the target areas, adding up to six inches of elevation to the marsh,” the release reads. “The work, known as thin-layer deposition, is expected to be completed by the end of December.”

This same technique was used in Middletown last year, where 11 acres of saltmarsh were raised at Sachuest Point Refuge. U.S. Fish and Wildlife Service Refuge Manager Charlie Vandemoer said that a large section of the Chafee Refuge may appear unrecognizable after the dredging process.

“For kayakers and other visitors to the refuge, the area south of Middlebridge may look more like a mudflat than a salt marsh once the construction work is finished,” he said. “But if we do nothing, we risk losing the whole marsh. The saltmarsh just can’t keep up with rising seas. Raising the elevation is our only shot at saving it for the long-term.”

According to tests carried out by the Coastal Resources Management Council, salt marsh vegetation will grow back after dredging at the higher elevation. Further, the Service and The Nature Conservancy will work with partners and volunteers next spring to begin replanting sections of the restoration area, and full vegetation of the marsh is expected back in 2018.

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