Posted on June 19, 2017
By Kaila Braley, Marshfield
After the emergency dredging at Green Harbor wrapped up this year, Marshfield town officials began looking at ways to repurpose material dredged up in the future.
Due to a misalignment of the jetties coming into Green Harbor, sediment builds up much quicker than it should, making the channel boaters use to get in and out of the harbor narrower and more shallow, Harbormaster Mike DiMeo said. The U.S. Army Corps of Engineers dredges the area nearly every year, and dumps the sediment offshore. But that may change if the town is able to secure a grant to reuse the material.
The Marshfield Planning Board has applied for a $36,000 coastal resiliency grant – which would include a $12,000 contribution from the town – to fund a study that would identify ways the materials could be used to the town’s benefit.
The town match would come from the beach revolving account, Town Administrator Rocco Longo said.
According to Town Planner Greg Guimond, one of the scientists from Woods Hold Group, which is working with Marshfield to improve the FEMA maps, saw the material being dumped offshore and suggested its use to nourish town beaches.
Guimond said the material could be used to build up the sand and dunes near the Duxbury town line, at the intersection of Bay Ave. and Bay Street, an area that hasn’t seen beach nourishment since the 1980s. He said it would likely take some time before all of the permits and funds are in place to do the work.
“Right now, when it’s high tide, the water comes up to the seawalls,” Guimond said. “In a storm event, this would protect the houses more.”
Guimond said the Army Corps would still drop the material where they’re placing it now, because the dredging vessels can only spend a limited time in each harbor. But the idea is the town would then bring in a barge to pump the material out to the beaches.
While most harbors require dredging every 10 to 15 years, Green Harbor really needs it annually, DiMeo said. With no dredging done last year, he said access to the harbor entrance was far worse this year. Where it should be about 100 feet wide, the channel was only about 25 to 30 feet wide before the emergency dredging, said DiMeo.
The dredge material could be used as beach nourishment, could bolster seawalls, or it could be stored and sold to other towns that need material for beach nourishment, DiMeo said.
Selectmen Chairman Michael Bradley estimated the material that was dredged this year was worth $550,000.
“Let’s not put this off,” Bradley said. “Let’s make sure we put this in place.”
If the town gets the grant, the project would include assessing the existing conditions, including tides, dredging history and sediment characteristics. The study would then evaluate the economic feasibility, possible locations for the sediment to be placed, nourishment design and stakeholder coordination.
Guimond estimated the town would learn by the fall if it will receive the grant.
Source: Marshfield
