Pioneer species of salt marsh plants are beginning to return to the Duck Harbor basin in Wellfleet.
The growth of glasswort and salt marsh spike grass follows the clearing of 80 acres of dead trees and other upland vegetation as part of the restoration of the Herring River.
It’s a microcosm of what will happen in the future, all along the river, when salt water tides are allowed to return to the artificially drained marsh, said Geoffrey Sanders, chief of natural resource management and science at the Cape Cod National Seashore.
“It's kind of exciting,” he said. “Three or four months ago, you stood in Duck Harbor and .. you looked out and you saw kind of a barren landscape of chipped wood. Now you look out there and you see a lot of green, and all that green that's coming back is all salt marsh species.”
The National Seashore and the town of Wellfleet are leading the Herring River restoration project with help from numerous partner agencies and organizations. The project is the largest-ever estuary restoration in Massachusetts.
This summer, they’re working with a consultant to study how best to raise the elevation of the former marsh in Duck Harbor, and how high it should be. When the salt marsh dried out, the sediment shrank, sinking down below sea level by up to three feet in some places. Those areas will be too low to support salt marsh vegetation once the tides return.
The project planners hope to move sediment once used to make artificial berms along the Herring River and place it on the low marsh to raise the elevation.
The project’s biggest step will come in 2025, when a new bridge under construction at Chequessett Neck will allow more tidal flow. Additional infrastructure changes, including the raising of roads to higher elevation and installation of larger culverts, will increase water flow and make the Herring River area more resistant to sea level rise.
Project coordinator Carole Ridley said another benefit of the restoration will be the return of more than 200 acres of harvestable shellfish habitat. And salt marshes absorb more carbon than they release, so they have a climate change benefit as well, she said.
Tides on the Herring River have been restricted by human intervention for more than a century. Over time, the plants and animals that live there have changed, making it more of a freshwater environment.
