The Shawsheen River runs gently but steadily through Andover, twisting around rocks. But just downstream there's a lot of action. An excavator on the banks of the river picks up rocks from a pile and drops them in the sediment. The crew here will top the rocks with soil in an effort to restore this riverbank.
Until just a few weeks ago, there was a dam here.
“It was attached to these two buildings here," Bill Bennett, a biologist with the U.S. Fish and Wildlife Service, explains at he points out the old sluiceway once used to lower the water level.
Thousands of aging dams like this one block rivers and streams across Massachusetts. Long past their prime, the dams damage ecosystems and could lead to dangerous flooding if they fail. Now, an effort is underway to remove some of them.
The state got a four and a half million-dollar federal grant to remove the Andover dam, which was built in the 1770s to power a woolen mill, and eight others considered high-risk. Bennett says there are about three thousand dams on Massachusetts rivers that no longer serve any functional purpose.
Click on the dots below to learn about conditions at individual dams in Massachusetts that could pose a risk if they fail.
“And so a lot of these dams were built to kind of harvest the power of our rivers, but then those industries go away," Bennett says. "But the dams are left behind.”
These dams can be a real barrier to fish swimming down river, according to Bennett. Before this dam — and a lot of others — were built on the Shawsheen, the river used to be home to herring, American eel, American shad, and Atlantic salmon. Restoring that lost ecology is one of the key reasons work is underway to remove some of the state’s 3,000 obsolete dams.
Safety is another reason. Tim Purinton is the director of the state’s Division of Ecological Restoration. He remembers 2005, when the wooden top of a dam on the Mill River in Taunton began to buckle. “The worry was it was going to be a catastrophic breach and create an inundation zone, a flooding zone downstream," he says. "Like a wall of water.”
Residents of Taunton were evacuated from the area that would flood if the dam failed. Fortunately, they managed to stop the failure and have since removed the dam.
“It was a wake-up call for Massachusetts, and it really put an emphasis on the need for looking at our infrastructure," Purinton says.
After that, state officials started going around checking the strength of dams and requiring that dangerous ones be fixed or removed.
About 950 dams could pose a risk to people or property downstream if they fail. Of those, 229 got a poor or unsatisfactory rating in their most recent inspection — meaning they’re somehow deficient even under normal conditions.
One of the dams under scrutiny is in the Roberts Meadow Brooke in Northampton.
“We own the dam, and we have a responsibility to meet the requirements that are being imposed upon us by the state," Northampton Mayor David Narkewicz says. "The state is not providing us funding to repair dams. They’re basically telling us that we have to either repair it or remove it. And so we believe that the best course of action is to remove the dam.”
Not everyone in town agrees. "We wanted to see it stay. It’s been there since 1883,” says John Clapp, who has lived in Northampton his whole life. Clapp loves the reservoir the dam created. “You go down, sit there, you can watch all kinds of wildlife — and the ducks and the blue herons, and we’ve seen many otters, many times on the ice feeding on fish. It’s just a beautiful spot.”
For years, Clapp and others in town have been fighting the plan to demolish the dam, worried that it would drain most of that reservoir and potentially contaminate the river with sediment.
It’s not easy to remove a dam. In Northampton and many other towns, it’s meant years of ecological and hydrological studies, heated public hearings, regulatory hurdles, and a significant financial investment.
Tim Purinton of the state Division of Ecological Restoration acknowledged there’s a lot more work still to be done to remove and repair all the dams that need it.
“ We’ll get there," he said. "I mean, it’s going to take a while, but I can say we’re putting a really strong college try towards it.”
In the meantime, they’re going to be watching closely this spring to see what fish make it upstream of where they just removed the dam in Andover, for the first time in nearly 250 years.