Posted on November 3, 2021
WESTERLY — A dredge project at Winnapaug Pond might wind up removing less sediment than originally expected.
Interim Town Manager Shawn Lacey, during a Town Council meeting on Monday, said he recently learned that the project, which started with the set-up of equipment last month, might result in the removal of just 54,000 cubic yards of sediment rather than the 70,800 cubic yards announced by town officials in December.
The reason for the difference? Changes in sediment levels caused by the natural force of the tide.
“I didn’t realize but the depths of the pond and the sediment changes with every single tide. You can check a specific area of the pond and check again 30 days later and find a 10,000-yard difference,” Lacey said.
The primary goal of the project is eel grass restoration. The lead agency coordinating the project is the U.S. Army Corps of Engineers. The federal government has allotted $2.4 million in federal funds for the project and the town has agreed to pay $300,000 as a non-federal match.
If the 70,800-cubic-yard figure is not reached, Lacey said, the town will qualify for a rebate, but he noted the largest cost drivers of the project are associated with setting up and breaking down equipment, costs that he said remain stable regardless of how much sediment is removed.
The revised sediment removal estimates were based on surveys conducted by the U.S. Army Corps of Engineers just prior to the actual dredging starting late last week. Prior work on the project involved setting up 10,000 feet of pipes that were delivered on dozens of tractor-trailers that were driven across the country from Wisconsin, the home state of the contractor performing the dredge.
After discussions with the state Coastal Resources Management Council, a state partnering agency on the project, officials agreed to attempt a deeper dredge at one of the three areas in the pond that have been selected for the project. By going deeper, the project might end up hitting the original 70,800-cubic-yard goal, Lacey said.
Areas of the pond to be dredged have to be closely surveyed to avoid damaging shellfish and other habitats, Lacey said.
Dredged sand is currently being pumped on to Misquamicut State Beach. Depending on the volume of sand that is ultimately removed, some sand might be pumped to the Town Beach and some onto Wuskeneau Beach, Lacey said.
The sand pumped from the bottom of the pond is initially dark in color because the pond serves as a filter. After about 30 days on the beach, Lacey said, the sand is expected to transform into a more common sand-like color.
A maintenance plan associated with the project should keep the project areas free from excessive sediment in the future, Lacey said.
Residents and others who use the pond have complained for years, saying sediment was building up on the bottom of the pond, making some areas impassable for boats.
