Removing old dams in Mass. even more urgent with stress of climate change

PLYMOUTH, Mass. — More than 3,000 dams -- many of them hundreds of years old -- are still in existence all over Massachusetts.

They're often outdated and unsafe, and the state is in the process of removing many of them. Climate change is making the need to get rid of them more urgent.

One of the largest projects right now is the removal of the Holmes Dam and Newfield Street Bridge in Plymouth.

"It’s one of the of the biggest projects that our division has ever assisted on," said Nick Wildman, a restoration specialist with the state’s

. "It's about a $6.7 million implementation to remove what was a high hazard dam." %

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This multi-year project, which should be completed by this summer, will allow Town Brook to flow freely back into the Atlantic Ocean.

"Most of the dams in Massachusetts date back either to the Colonial times or the Industrial Revolution when they were initially built to provide energy to grist mills,” explained Wildman.

Many of the dams around the state are obsolete and haven’t been maintained properly. That can create a real threat, like when the Whittenton Pond Dam in Taunton came close to failing in 2005 and forced wide-scale evacuations.

David Gould, the environmental officer for the town of Plymouth, is happy to see the Holmes Dam come down.

“When people think of dams, there is a potential damage with the water being released," he said. "A lot of those older dams also have a tremendous amount of sediment behind which would be released downstream which would smother habitat.” %

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It’s not just the fears of rushing waters and mudslides that motivated the Baker Administration. There is also concern about how climate change is impacting these dams.

>> Hundreds of Mass. towns need a plan for climate change, Baker says

"As we have seen larger storm events from climate change, this aging infrastructure is really under threat for failure and other maintenance problems," Wildman added.

Allowing rivers to run free can also provide another type of protection against rising oceans.

"They also move a lot of sand and sediment," said Wildman, “and over time, as that moves out to the ocean, it builds up our marshes and barrier islands which are under threat from the changing conditions of the sea.” %

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Other species can reap benefits when old dams are removed. Herring is able to spawn farther upstream and then return to the ocean in greater numbers. The result: more food for sea bass, tuna and cod. This is one of the reasons the Elm Street Dam in Kingston is now in line for removal.

Some dams near the coast can make flooding worse during storms. As tidal waters rush in, they can't go upstream when they hit the dam, threatening homes and property in the area.

“Dam removal is an integral part of climate change resiliency,” said Wildman. About 40 dams have been taken down over the past dozen or so years.

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Cox Media Group