As the climate changes, obsolete dams put Mass. at risk for flooding similar to Vermont

With flooding in Western Massachusetts, Vermont and New York following recent torrential downpours, experts say thousands of obsolete and often crumbling dams across Massachusetts puts the state at increased risk. That risk only grows, they say, as climate change makes severe storms more common.

“A lot of these dams are really old,” said Cathy Bozek of the U.S. Fish and Wildlife Service. “A lot of them were built to power old mills [and] factories, and they’re not being used anymore. They’re obsolete dams, and many of these dams are not being maintained. They are in unsafe condition and are subject to failing during heavy storms.”

Of the roughly 3,000 dams in Massachusetts, about 1,300 are large enough to be listed in the National Inventory of Dams kept by the U.S. Army Corps of Engineers. Of those, 328 are ranked as having “high hazard potential.”

“Which means that loss of life and significant damage to homes, buildings, infrastructure is likely if the dam fails,” Bozek said. "An additional 643 are 'significant hazard' rated. And that means that there may not be loss of life, but it can cause significant economic loss, environmental damage and disruption of lifeline facilities."

In Vermont’s capital, Montpelier, officials said early Tuesday morning that the nearby high-hazard Wrightsville Dam was close to capacity. Overflowing had “never happened since the dam was built so there is no precedent for potential damage,” City Manager William Fraser warned. The water level ultimately subsided, but the city was still left with extensive destruction: many businesses and Montpelier’s City Hall are closed while they recover, and one man died.

In Massachusetts, Bozek recalled the near-failure of the Whittington Dam in Taunton in 2005 during a strong storm. Thousands of people were told to evacuate the city’s downtown, which sits about a half-mile downstream from the dam.

"They had to declare a state of emergency," Bozek said. "That one ended up having emergency repairs and they were able to save the dam and there was no loss of life. But it was a huge risk, and Massachusetts certainly is in danger of seeing significant flooding and infrastructure damage from dam failures in the future."

Standing by the Watertown Dam in Watertown on Wednesday, Robert Kearns of the Charles River Watershed Association pointed to rushing water and recalled a spring Nor’easter in 2010 that brought days of rain to the area.

“Back in the 2010 storm, the water on the opposite side of the river came over the earthen embankment and really went over and around the dam,” he said. “A lot of these structures are just either totally left forgotten or are really not designed for the strongest storms, the more increased rainfall that we're seeing here in the Northeast with climate change.”

The Watertown Dam is owned by the Massachusetts Department of Conservation and Recreation, Kearns said, and the Charles River Watershed Association is pushing for the department to remove it.

“We’re really hoping that they'll make the right decision,” he said.

Craig LeMoult GBH News

DCR did not make anyone available for an interview, but a spokesperson sent a statement regarding the recent storm.

“Dams overflow for a number of reasons, including weather conditions and a blockage of water flow. However, a dam overflow is not the same as a dam failure,” the spokesperson said in the written statement. “So far, there have not been any dam failures or emergency conditions reported to the Office of Dam Safety following the recent weather conditions. We will continue to monitor dams across the state and will respond to any reports of emergencies or failures.”

Several dam removals are underway in Massachusetts, including a current project at the High Street Dam in Bridgewater, Bozek said. One barrier to removal — the high cost associated with carefully taking down a dam — eased after billions of dollars were made available under the 2021 federal infrastructure bill.

“Through the bipartisan infrastructure bill and other funding opportunities, we’re bringing a lot of support for these projects, and we’re able to move a lot of them forward,” Bozek said. “And so, we’re seeing great progress in working with the dam owners, working with communities and really bringing a lot of these projects into implementation.”

In the case of a dam overflowing or failing in Massachusetts, Kearns said there's not enough publicly available information about what the likely impact would be.

“Here in Massachusetts, there's not a database online where the public and first responders can go and look at if a dam were to fail ... where would that water go?” Kearns said. “That information is in the emergency action plan that some first responders have, but it's not as publicly available as in other states like California, where ... you can look up every dam that's a significant or high hazard dam and see, if that were to fail, where that water would go.”

FEMA’s flood maps for the commonwealth are also outdated, he said.

“A lot of the areas that have flooded in Vermont are not in the FEMA flood zones,” Kearns said. “So, FEMA flood zones are based on past data ... past floods. But we’re seeing floods today that we haven't seen in the past.”

Some cities, like Boston, have updated flood maps that project into a future impacted by climate change.

“But really, the state really needs to do this across the whole commonwealth because people are going to be vulnerable,” Kearns said.

Making that kind of information more widely available, piece by piece, is one of the ways the Charles River Watershed Association is trying to address the problem.

They worked with 20 cities and towns along the Charles River to create a simulation of flooding along the Charles, using climate projections for 2030 and 2070.

“With our regional outlook, we’re better able to understand inland flooding impacts and determine the most effective solutions,” said the Rev. Vernon K. Walker, program director of Climate CREW (Communities Responding to Extreme Weather), which is helping CRWA with community engagement on the project.

Using those projections, the project is helping those municipalities make changes now to prevent flooding in the future.

“We’re looking at building green storm water infrastructure,” Walker said. “We’re looking at reducing impervious cover. We’re looking at land conservation and increasing the tree canopy. And all these are potential opportunities for flood water storage.”

And for when those floods eventually do hit, Climate CREW is prepared to give community members “to-go” emergency bags with items like flashlights, can openers and waterproof matches.

Correction: This story was updated to clarify the roles of the Charles River Watershed Association and Climate CREW in the flooding simulation project and outreach.