Dredging News Online US: CRMC celebrates Ninigret Pond salt marsh restoration project

Environmental Issues // December 6, 2016
The Rhode Island Coastal Resources Management Council (CRMC) recently celebrated the impending start of work on the Ninigret Pond Salt Marsh Restoration and Enhancement project in Charlestown with project partners and town officials at a ceremony at the breachway.

“We’re all in this together, and thank goodness, because this is critical. We know that the sea levels are rising, all across the world, but in Rhode Island, it has a huge impact on us,” said Senator Jack Reed, (D-RI). “It has an impact on our way of life, our economy, on maintaining our homes. We have to take positive action, and this is positive action.”

Reed was chair of the US Senate Appropriations Subcommittee on the Interior, Environment, and Related Agencies at the time the funding was awarded for the project, and was instrumental in securing the funds for Rhode Island.

Starting the first week of December, crews will be dredging within the Charlestown Breachway, and will then reuse that material on the adjacent Ninigret salt marsh to increase its elevation to make it more resilient to the impacts of climate change and sea level rise. The goals of the project are to preserve the functions of the existing salt marsh making it more resilient to future sea level rise, to slow the entry of sediment into the pond and to improve navigation by creating a deeper breachway channel.

Senator Sheldon Whitehouse, (D-RI), said the project was a great one, bringing together many state and local partners, as well as non-governmental agencies to protect one of the state’s many beautiful natural resources.

“What a gem we live in – look at this,” he said, gesturing to the marsh behind him. “But it’s also got a little hint of a warning in it. What we’re seeing now is sea level rise accelerating…and now the pace of sea level rise has gone ahead of the ability of our marshes to keep up naturally, so now we have to do it ourselves. And it’s great work, but we should take away from this a warning that the basic operating systems of our environment are starting to go haywire, and we have a short window of opportunity to try to resolve that.”

The CRMC has contracted with JF Brennan Company Inc., an environmental services and marine construction firm that specializes in waterway remediation and habitat restoration to dredge two sedimentation basins within the breachway channel.

Most of the material that is dredged will be discharged from pipes onto the marsh to the west of the channel. The discharged material will then be spread and graded to elevations that are appropriate for salt marsh plants. Some of the material dredged from the basins will be discharged along the shore, in the intertidal area to the east of the breachway. This will help to re-nourish the beach along the shoreline.

Congressman James Langevin lauded his fellow legislators for their continued steadfast work in Washington, as well as the CRMC and project partners for their hard work on the project. “This really is an excellent example of what a successful partnership is, when the federal, state and local governments work to preserve our natural resources,” he said. “You are having an impact for generations to come. I know that we cannot fight Mother Nature, but hopefully we can work with her to mitigate the effects of sea level rise and super storms. We can’t let up on the effort, and we’ll have to get smarter and more resilient.”

“Sea levels in Rhode Island have been rising at an increasing rate, particularly over the last 30 years. Observations in many of Rhode Island’s salt marshes – including the marshes in Ninigret Pond – confirm what our models are telling us: that salt marshes are beginning to drown in place, converting to mud flats or open water.

“Salt marshes perform many important functions, including acting as a natural buffer to storms and providing protection for communities along our shorelines. Within the Charlestown breachway in Ninigret Pond, sand has been accumulating as it is swept in by shoreline currents. As it enters the pond it covers eelgrass beds—an important habitat—and makes navigation difficult for the many boaters who enjoy the pond.”

“We know that in Rhode Island, our marshes are under considerable stress from accelerated sea level rise, so the goal is to enhance the marsh and improve its resilience to sea level rise,” said Caitlin Chaffee, CRMC coastal policy analyst. “We hope this project will serve as a win, win, win – one, to restore the important ecological habitats we have here. The second win is protecting our coastal communities – by restoring these habitats, we can really improve the resilience of this coastal barrier system, thereby protecting our coastal communities. The third win is the other community benefits this project represents – the dredging will improve navigation for people who recreate on the pond…and those [sedimentation] basins will trap sediment that would otherwise smother those eelgrass beds.”

The JF Brennan crew is currently mobilizing the dredges, barge, and other equipment near the RIDEM state boat ramp and campground to the east of the breachway. Boat ramp access will be temporarily blocked while a crane is used to move equipment into the channel. Visitors should use caution and heed signage to avoid the active construction areas and equipment. Dredging was scheduled to begin on 5 December. Once equipment is deployed, access to the boat ramp will remain open. Boaters should use caution when navigating the breachway channel while the dredging machinery is in operation.

Dredging will occur six days a week, 24 hours per day until the project is complete. Dredging is anticipated to be completed by the end of January. Work on the salt marsh will begin shortly after dredging begins, and will continue through January. The salt marsh work will be done using a lightweight, amphibious excavator, and is anticipated to be completed no later than mid-April. Planting of the marsh will occur in the mid to late spring. Ecological monitoring of the site is ongoing and will continue after the project is completed.

Immediately after the dredged material is spread and graded, the marsh will look much like a mud flat—a bare area of exposed sediment. Over time, salt marsh grasses will begin to recolonize the covered areas.

Save The Bay will be working with CRMC to plant a portion of the restored area to ‘jump start’ the natural recolonization process. Many of the plants to be planted will come from seeds collected here in Rhode Island with the help of the New England Wildflower Society. Over the next few years, it is anticipated that healthy salt marsh grasses will again cover the restored marsh. The breachway channel will be deepened significantly to create basins where sediment can accumulate over time.