The latest flooding in Vermont has added fresh urgency to concerns about the hundreds of dams in the state, a third of which are more than a century old.
The July 10-11 deluge from the remnants of Hurricane Beryl was not as bad for the hundreds of dams across the state as compared to last year's floods, when five failed and nearly 60 overtopped. But the second bad flood in a year raises concerns about the viability of these structures as climate change brings heavier rains and more powerful storms.
"The many thousands of obsolete dams that remain in our rivers do not provide protection from flooding, despite what many may think," Andrew Fisk, the northeast regional director of American Rivers, an environmental advocacy group, said in speaking to the Associated Press (AP).
"Dams not created specifically for flood protection are regularly full and do not provide storage capacity," he added. "And they also frequently direct water outside of the main channel at high velocities, which causes bank erosion and impacts communities."
The challenge facing dams in Vermont is playing out across the country as more of them overtop or fail during heavy rains. The Rapidan Dam, a 1910 hydroelectric dam in Minnesota, was badly damaged in June by the second-worst flood in its history; and in Texas, flooding damaged the Lake Livingston Dam's spillway about 65 mi. northeast of Houston.
There are roughly 90,000 significant dams in this country, according to data from the U.S. Army Corps of Engineers (USACE), of which at least 4,000 are in poor or unsatisfactory condition and could kill people or harm the environment if they failed. To guard against such catastrophes, they need regular inspections, upgrades and even emergency repairs.
Like the rest of New England, Vermont has mostly older, small dams built to power textile mills, store water or supply irrigation to farms. The concern is they have outlived their usefulness and climate change could bring storms they were never built to withstand.
Two Years of Flooding Put Dam Safety in Spotlight
The July 2023 floodwaters in Vermont drew outsized attention to dams mostly due to the failures and near failures, according to AP. In the capital city of Montpelier, for instance, a dam was at risk of sending water over the emergency spillway and through parts of the town.
The National Inventory of Dams, a database regulated by the USACE, lists 372 dams in the state, with 62 rated as high hazard, meaning lives could be lost if the barrier fails. Ten of those were rated in poor condition, which means remedial action is necessary.
State officials told the AP they actually regulate 417 dams and that there are hundreds more too small and of minimal hazard to be regulated.
The flooding rains last summer led to a rapid inspection of all dams in Vermont, with more than $1.5 million spent to stabilize and repair storm damage.
"The team had never been faced with a situation [where] 8 inches of widespread rain [fell] across essentially the entire state of Vermont," explained Neil Kamman, director of the Water Investment Division of the state's Department of Environmental Conservation. "It stressed all of the facilities that the state of Vermont owns and that the dam safety team manages but filled up hundreds of dams, caused the failures that you know about, and created a whole bunch of unknown uncertainties out there on the landscape in terms of downstream risk due to … prospective dams having been destabilized."
In response, the Vermont Legislature approved the hiring of four staffers in the state's dam safety program, bringing the total to nine, and allocated an additional $4 million to a dam safety program, up from $200,000. That money can now be used for emergency risk reduction, restoration or dam removal.
Vermont's Dams Held Up Well During This Year's Floods
Luckily, after the most recent flooding earlier in July, Vermont officials said the damage has been minimal. No dams are believed to have failed and only one — Harvey's Lake Dam in Barnet, which is classified as a low hazard structure — overtopped. But even in that case, there was not likely to be any significant impact to property nor the nearby roadways, the AP learned.
Julie Moore, secretary of the Vermont Agency of Natural Resources, said during a news conference July 12 that inspections found the Winooski River Valley flood control reservoirs "continue to do their job well" and that levels at the Waterbury Reservoir "are stabilizing with plenty of storage remaining."
Those dams, along with the East Barre Dam, are critical to flood control in an area that stretches from Barre to Essex.
Moore also said that officials had completed inspections at "seven particularly at-risk" dams in the northern part of the state and that "no damage was identified."
The floods this year came too soon for the additional money and staffing to have an impact, but Kamman said the experience of responding to 2023's flood helped shape a more robust response from the team this time around.
"The biggest difference between the response this year and last year is the fact that we had the game plan worked out for a widespread event that could stress a large number of facilities all at once," he explained.
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