Two dredges are now running 24 hours a day, six days a week on Quonochontaug Pond, suctioning material from the breachway and depositing it on the adjacent salt marsh as part of the Rhode Island Coastal Resources Management Council (CRMC) salt marsh restoration and elevation enhancement project.
Contractor J.F. Brennan, which also worked on a very similar project in Ninigret Pond in 2017, arrived on-site during the first week of December, using an oversized crane to assemble pipe sections and the dredge barges.
With the oversight of the CRMC, dredging has begun on a section to the west of the state boat ramp at the end of West Beach Road. That material is being spread on a 10-acre section of marsh on the west side of the breachway.
The second phase of the project will include dredging a channel north from the breachway into the pond, with that material to be spread over a 20-acre area of the marsh on the eastern side, some of which is now open water.
The majority of funding for the $2 million project comes from a coastal resilience grant from the National Oceanic and Atmospheric Administration. The Town of Charlestown has contributed $450,000 to the effort, and the CRMC-administered R.I. Coastal and Estuarine Habitat Restoration Program and Trust Fund also dedicated $90,000 of funding from FY 2018.
Local nonprofit groups The Shelter Harbor Conservation Society and the Salt Ponds Coalition have raised a significant amount of funding for the project from their membership, and the US Fish & Wildlife Service’s Coastal Program will be providing additional support.
The project at Quonnie will mirror the one completed at Ninigret in its scope and size: approximately 30 acres of heavily degraded salt marsh will be restored and elevated through sediment placement and native marsh grasses will be planted in the spring to help nature along in revegetating the restored areas. The placed material will increase the elevation of the degraded marsh so that it can better withstand increased flooding from storm events and sea level rise.
“The primary goal of salt marsh enhancement projects is to help our coastal marshes be more resilient to increased flooding and sea level rise,” said Caitlin Chaffee, policy analyst and project manager for the CRMC. “Rhode Island’s salt marshes have been declining in condition in recent years, and like the Ninigret project, we hope this restoration effort will buy the marsh at Quonnie more time.”
The area north of the Quonochontaug Breachway will be dredged for the first time since the breachway’s construction, creating an eight-foot-deep channel, and the other area to be dredged, an east-west channel, will be dredged to a depth of approximately four feet, optimal for eelgrass growth. A small barrier spit at the end of the parking area will also be restored with dredged material and plantings, to create a small beach for recreational purposes.
After the project’s completion at the end of January 2019, partner Save The Bay will come in to oversee the planting of native grasses, as well as the creation of more natural, meandering drainage channels, to mimic the natural hydrology of the salt marsh.