Dam Safety

Amid ‘extreme’ rainfall, FirstLight says Connecticut dam is not in danger

Stevenson Dam is structurally secure and is operating as it was designed to and is not in danger of failing, FirstLight said.
Amid ‘extreme’ rainfall, FirstLight says Connecticut dam is not in danger
(By Rootology - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4474725)

Amidst “extreme” rainfall in western Connecticut and associated flooding in the Lower Housatonic River area, FirstLight said Stevenson Dam is structurally secure and is operating as it was designed to and is not in danger of failing.

Heavy rainfall often brings high water levels and heightened river flows on the Housatonic River, causing flooding in low-lying areas, particularly in Lower Housatonic communities. Stevenson Dam is not a flood control facility, meaning what flows down the river must be passed through the dam at the same rate, FirstLight said.

The 28.9 MW Stevenson Dam Hydroelectric Plant began construction in 1917 and was completed in 1919. A fourth turbine was added to the powerhouse in 1936. Stevenson Dam also creates Lake Zoar, one of Connecticut’s largest lakes.

During high-flow events, FirstLight operates its Housatonic River hydroelectric facilities under protocols approved by the U.S. Army Corps of Engineers, per its Federal Energy Regulatory Commission (FERC) license. Within the constraints of its licenses, FirstLight works to accommodate high flows and communicates with relevant agencies, local officials and lake authorities to ensure awareness of river conditions, it said.

FirstLight said it takes several steps to prepare for and manage high-flow events, beginning with the constant monitoring of United States Geological Survey (USGS) gauges and communication with the National Weather Service River Forecast Center, allowing it to anticipate, plan and prepare for the river conditions.

FirstLight also launched a flood notification system for communities downstream of Stevenson Dam, which issues emergency notifications when flows exceed a certain threshold and flooding is possible.