In December, about 2 million gallons of water from the Beaver River rushed through Richmond.
A small, dilapidated dam, likely built 150 to 200 years ago, had been quietly holding back the water, says Tim Mooney, marketing and communications manager for The Nature Conservancy of Rhode Island.
That is until a rainstorm at the end of one of Rhode Island’s rainiest years on record washed away the dam that had been inhabited by beavers.
The repercussions of the failure were relatively minimal, limited to some road flooding and a broken utility pole. But as Rhode Island continues to see increasing rainfall, it’s likely more of the state’s 670 dams will falter.
“If we continue to break rainfall records, it wouldn’t be surprising if some of these small dams start to let go,” Mooney said.
For some smaller dams, this isn’t necessarily bad news.
Removing the dams can be good for brook trout and other organisms because they can move more freely in the river and the water flow reduces the water temperature, Mooney says. Brook trout are cold-water animals and dams create shallow ponds that heat up easily in the summer – essentially creating a bathtub in the middle of the river – and harm the fish habitat.
Now that the dam is gone, Mooney says, The Nature Conservancy plans to monitor the water temperature and track what happens to help make a case for removing other small dams.
There are hundreds of other small dams like the one on Beaver River that the Nature Conservancy is looking to remove to help the ecology of rivers and reduce flood risk, Mooney says.
But dam removal is very expensive – costing anywhere between hundreds of thousands of dollars to millions – and Mooney says getting the money, machinery and permits proved too difficult in the case of the Beaver River dam.
“In the end, nature took care of it for us and we’re certainly not going to replace it,” Mooney said.
But while that dam failure proved beneficial, failures elsewhere could be catastrophic.
Out of the state’s 670 dams, 95 are classified as “high hazard,” meaning their failure would “result in probable loss of human life,” according to the R.I. Department of Environmental Management’s 2023 Dam Safety Report. Another 81 were deemed “significant hazard,” where a failure would cause “major economic loss, disruption of lifeline facilities, or impact other concerns detrimental to the public’s health, safety or welfare.”
Amanda Cantrell, DEM chief of staff, says the classification of “high hazard” is not related to the condition of the dam. But because they pose the most risk, DEM focuses its attention on making sure these dams are in safe condition.
However, DEM is concerned that a higher frequency and more intense storms will cause more high- and significant-hazard dams to fail, especially those that aren’t meant to pass the amount of water from the storms, Cantrell says.
The report shows DEM faces several challenges in addressing dam safety, including low funding, staffing shortages and unclear ownership of dams.
Cities and towns have also fallen behind on creating necessary emergency action plans in case of the failure of high-risk dams. Since 2008, when the plans were first required, only 77 of the 176 high- and significant-hazard dams have approved plans. DEM has issued letters and conducted workshops to help with the process plans to begin issuing violations against municipalities that do not have plans in place this year, according to the safety report.
In Westerly, groups have been working for years to remove the Potter Hill Dam along the portion of the Pawcatuck River that forms the border between Westerly and Hopkinton.
The dam was first constructed in the late 1700s and rebuilt in the early 1900s to power a now-abandoned mill on the Westerly side of the river.
While DEM has classified the dam as low hazard, Mooney says Westerly town officials were concerned it was going to fail and approached the Nature Conservancy for help years ago.
Several other groups such as the U.S. Fish & Wildlife Service, the Wood-Pawcatuck Watershed Association and National Oceanic and Atmospheric Administration have also teamed up to remove the dam.
If the dam, which is holding back around 6 miles of the river, were to fail, James Turek, a restoration ecologist with NOAA, estimates it could cause several millions of dollars in damage to surrounding towns. Removing the Potter Hill Dam would also have benefits to the fish and wildlife while reducing flood risks and improving public access to the Pawcatuck River.
Hopkinton and Westerly residents have rallied against the project, raising concerns about downstream flooding, wells drying up, and reduced property values and riverfront views. Turek says property values could actually increase because of lower flood risks and the aesthetics of the river will likely be similar if the dam is removed.
In January 2022, the Westerly Town Council voted to essentially kill the dam removal project. Then a year later, a new council reintroduced the idea and voted that a full dam removal is its top preference among several options that were introduced. Two other alternatives were chosen for further study and engineers must study the possibility of all three options.
