The state wants to maintain the Waterbury Reservoir at year-round summertime water levels, a decision it says will enhance water quality, wildlife habitat and recreation.
The Department of Environmental Conservation issued a draft water quality certification for Green Mountain Power’s hydroelectric plant at the Waterbury Dam on Thursday, a decision that aims to keep the Waterbury Reservoir’s water level more stable.
Under current practice, the reservoir is drained each winter to between 540 and 560 feet above sea level, and then slowly filled through the spring to reach its summertime average of 589 feet, according to the draft decision.
The winter drawdown is used to mitigate floods in the spring and maintain the generation capacity of Green Mountain Power’s 5.5-megawatt hydroelectric plant at the dam. But winter drawdowns can cause erosion, and result in increased water turbidity that disturbs fish, wildlife and aquatic plants, according to the proposed decision.
Green Mountain Power will be required to operate the dam in a run-of-the-river mode. The utility supports the department’s decision to maintain summertime water levels year round, according to company spokeswoman Dorothy Schnure.
The 2,130-foot-long, 187-foot-high dam was first used for flood control when it was built in the 1930s. In the 1950s, Green Mountain Power began operating a hydroelectric facility at the site. The utility now needs a new license from the Federal Energy Regulatory Commission.
The Waterbury Center State Park and the Little River State Park are located near the Waterbury Reservoir. Together the parks receive nearly 50,000 visitors annually who come to fish, boat, swim, hike and camp, according to the draft certification. The reservoir and its banks supports wildlife, including moose, white-tailed deer, red fox, otters and beavers, as well as many fish and other aquatic biota, according to the draft ruling.
Department of Environmental Conservation Commissioner David Mears said the proposed decision aims to balance protecting natural resources, recreational uses and flood control.
“It’s a real treasure in terms of a natural resource,” he said. “It’s been a challenging process to sort out how to balance all those decisions.”
The upgrades to the dam include replacing the existing 24-inch bypass pipe’s valve with one that can adjust flows, installing a more efficient turbine and repairing the gates, which control the flow of water through the dam.
Mears said the repairs should be completed by 2020. He estimates the repairs will cost approximately $40 to $50 million, of which the state would have to pay about $15 million.
He said the state will work with the U.S. Army Corps of Engineers to ensure the new water levels are safe.
