Vermont’s Department of Environmental Conservation is seeking help from the U.S. Army Corps of Engineers to improve two Winooski River flood-control dams, after July’s historic flooding pushed the facilities to their limits.
In a Sept. 11 letter, Neil Kamman, then serving as interim commissioner of the Department of Environmental Conservation, asked the federal agency to conduct two feasibility studies “to improve operational flexibility to discharge stored flood waters post-storm.”
Vermont’s historic summer rainfall, Kamman wrote, showed that the Wrightsville Dam and the East Barre Dam were “susceptible to a back-to-back storm event.”
The letter comes after rising water levels during July’s heavy rainfall strained Vermont dams. At the Wrightsville Dam, water levels rose to within a foot of the dam’s spillway, causing fears that water would pour into the already-swollen Winooski River and worsen flooding in the state’s capital.
“As you may recall, the water level came very close to the auxiliary spillway” at Wrightsville, Benjamin Green, a dam safety engineer at the Department of Environmental Conservation’s Dam Safety Program, said in an interview. “And then took a little bit longer time than we would have liked to draw back down to a more reasonable level.”
Effectively, state environmental officials would like to be able to safely let stored water out from behind the dams more quickly, without causing more damage. That would allow them to lower water levels to prevent overflows during storms.
The East Barre Dam, though it did not stoke as much anxiety as Wrightsville, is also vulnerable to repeated storms, Kamman wrote in his letter.
“Also, State Representatives from Barre City have inquired on several occasions if modifications could be made to the dam to further reduce storm outflows, particularly during high intensity, short duration events,” he wrote.
Rep. Peter Anthony, D-Barre City, said in an interview that he was “the culprit.”
Anthony, who was displaced by July’s flooding, said he had inquired about safety improvements to the dam after Tropical Storm Irene in 2011.
“Look, you know, even if you could save Barre one flood,” he recalled telling state officials, “that would be a blessing. And it would be cost-effective.”
The Wrightsville, East Barre and Waterbury dams are all owned by the Department of Environmental Conservation and perform key flood control functions.
The Army Corps of Engineers, however, helped design the structures and provides technical assistance when needed. The Corps is also helping with a years-long improvement project at the Waterbury Dam.
Bryan Purtell, a spokesperson for the U.S. Army Corps of Engineers, confirmed that the agency was in touch with the Vermont Department of Environmental Conservation.
The Army Corps is “currently discussing the technical assistance needs with our state contacts,” Purtell said.
It’s not clear who would pay for the two feasibility studies, if they do take place.
During July’s flooding, of the roughly 400 dams regulated by the Department of Environmental Conservation, four failed and there were “several partial breaches,” Green said.
Roughly 60 dams are believed to have sustained damage from the flooding, and state officials are still conducting inspections of damaged facilities.
“We had a good handful of dams that took a fair amount of damage,” he said. “And I think that overall we were pretty fortunate that it wasn’t worse.”
