EAST BRIDGEWATER — The Carver Cotton Gin Mill Dam was once an economic engine in this town south of Boston, harnessing the power of the Satucket River to run a major factory.
Today the 19th-century dam stands in disrepair, a shabby remnant of a bygone era. The onetime factory, windows knocked out and vines climbing its brick walls, has also seen better days.
After years of neglect, the dam has been slated for destruction, part of a statewide push to restore rivers to their natural state.
“When you remove the dam, you regain what you lost,” said Beth Lambert, aquatic habitat restoration program manager at the state’s Division of Ecological Restoration, which announced details of the demolition project last week.
There are some 3,000 dams in Massachusetts, a vestige of its milltown past. But just 10 percent serve an active purpose, either for energy or flood control, and many are structurally unsound. Over the past decade, state agencies joined by environmental groups have stepped up efforts to remove the outdated structures, allowing 100 miles of rivers to run free.
Removing the East Bridgewater dam, which now blocks a substantial population of river herring from traveling upstream, would open up several hundred acres of spawning habitat.
“It’s really holding back fish,” said Alison Bowden, freshwater program director for The Nature Conservancy, a leading environmental group that is working with the state to remove dams. “It needs to go.”
First built in 1815, the dam ranks among the worst 10 percent in impeding migratory fish, Bowden said. Each spring, alewife arrive at the base of the dam in hope of traveling upstream, but are blocked.
The privately owned dam was declared unsafe more than a decade ago. The owner, who had not made the necessary repairs, had asked for help in removing the dam, Bowden said, and town officials signaled their support for the project, which will be funded by the state, environmental groups, and the federal government.
“The town would be very happy to see this go forward,” said John Haines, the town’s public works director. “It would be a really significant project.”
The Brockton Enterprise reported plans to remove the dam on Wednesday.
The project will probably cost several hundred thousand dollars, officials said, and will take several years of planning. While the pace is slow, the benefits of removing dams are often significant.
The project will give fish such as alewife, American shad, white perch, and brook trout free passage to the river’s source, Robbins Pond. A fully recovered alewife population would approach 200,000 adults a year, one of the largest in the state.
Since 2004, Massachusetts has removed 28 dams, and numerous similar projects are in the works. Last week, the state announced plans to remove dams in Bellingham, Chilmark, Northampton, Revere, and West Boylston.
The Carver Cotton Gin company acquired the East Bridgewater property in 1842 and operated there until the early 1990s. It has since been home to various commercial uses, according to a project proposal from Kennebec Reborn, a Maine conservation group.
The existing dam was built in the early 20th century. In 2001, state inspectors found that the dam was in danger of failure and ordered the owner to open the flow gates to regulate water levels.