Three major hydroelectric dams on the Connecticut River between Vermont and New Hampshire could soon see a change in how water flows through them for the first time in more than four decades.
Great River Hydro, a subsidiary of Hydro-Quebec, owns the Wilder, Bellows Falls and Vernon dams, and has agreed to operate them as “run-of-river” facilities — where just as much water comes into the dam as flows out.
Environmental groups negotiated with Great River Hydro to secure this change, and the dam operator says it views the shift in operations as a positive one.
“This is a great and wonderful change, and we're in support of it,” said Kathy Urffer, with the Connecticut River Conservancy.
Right now, the dams are operated as “daily peaking facilities,” which pool water above them and release it when demand for power is high — usually once in the morning and once in the evening.
These sorts of facilities are very good at supplying on-demand, low-carbon power to the electric grid, and are widely viewed as critical backstops for keeping the lights on across New England.
But they are also notorious for creating erosion, altering river ecosystems and impacting water quality.
The changes are part of Great River Hydro’s bid to relicense the dams — which creates a once-in-a-generation opportunity for the public to weigh in on how they operate.
Multiple stakeholders including environmental groups and the state of Vermont have a say in the process, but the final conditions will be decided by the Federal Energy Regulatory Commission, or FERC.

Great River Hydro says the shift in water flow won’t have a major impact on the electric grid or on regional electricity prices. And the company will retain the ability to pool water above the dams for a set number of hours each month.
“We estimate there will be a small loss in revenue for us in operating this way, but … operating this way is really the right way to go,” said Jennifer Griffin, director of FERC license compliance for the company. It’s unlikely they would be granted a permit without making such a change, Griffin added. “It’s the way it seems like hydro is heading and it’s more beneficial to habitat.”
Environmental groups like the Connecticut River Conservancy are pushing for other changes, too. They would like state and federal regulators to require more environmental review before the plan is enacted and more robust plans for expanding recreational access to the river. They also want upgrades to the dams’ fish ladders, particularly after independent scientists discovered evidence of federally endangered shortnose sturgeon below the Bellows Falls dam last year.
Ted Castros-Santos is a researcher who studies fish passage for the U.S. Geological Survey, a federal agency. He says sturgeon struggle to navigate fish ladders like the ones in place at the three Vermont dams, but a fish lift could yield better results.
“Once they're in, you can have 100% or very close to 100% successful passage,” Castros-Santos said.
Fish presumed to be shortnose sturgeon were spotted below Bellows Falls dam. (Micah Keiffer / Courtesy)
Great River Hydro has committed to upgrading its fish ladders over the next 16 years to better accommodate migrating American eel, shad and lamprey, but environmental groups say that timeline is too long and the company should make specific accommodations for sturgeon.
The relicensing process has also raised concerns from farmers along the Connecticut River, many of whom say they’ve lost valuable fertile land to erosion caused by the dams.
And while the draft plan would require Great River Hydro to study erosion impacts after the new license is issued, farmers say regulators aren’t doing enough to protect their operations.
“Erosion is probably the biggest problem for us,” said Mike Snow, a farmer in Post Mills who leads the Connecticut River Watershed Farmers Alliance. “What happens if there is more erosion? ... Do we compensate landowners? There’s no conversation about that and we think there should be.”
Griffin said the company believes its new operating plan will reduce erosion, and that a separate analysis isn’t necessary.
The deadline for public comment on the federal draft Environmental Impact Statement, where federal regulators outline what sort of monitoring and review will be required for all three dams to be relicensed, is August 28.