The freezing temperatures that have gripped the region could bode well for those hoping Candlewood Lake will be less infested next summer with Eurasian watermilfoil.

For years, FirstLight Power Resources has lowered water levels over the winter in an effort to expose parts of the lake bed to the cold and kill the invasive plant, which has long been a nuisance for swimmers and boaters. The levels were lowered for a second time this winter within the last week.

“Overall, this weather is very encouraging,” said Greg Bugbee, who oversees the Invasive Aquatic Plant Program for the Connecticut Agricultural Experiment Station.

Temperatures below 27 degrees generally are low enough to kill the weed. But temperature isn’t the only factor: The sediment must also be dry and the milfoil exposed to the air.

“Anything still covered by water is not going to be affected,” Bugbee said.

Snow acts as an insulator, Bugbee said. It might be minus 30 degrees outside, but the ground underneath the snow could be much warmer.

“A lot will have to deal with the snow cover,” Bugbee said. “It’s perfect conditions if it’s little or no snow.”

FirstLight varies the amount of water removed from the lake during the winter during a draw-down, from several feet in a shallow draw-down to as many as 10 in a deep one.

FirstLight began drawing down the lake in mid-December and reached the target depth — between five and seven feet lower than normal summer levels —

(Dec. 29), said Len Greene, a FirstLight spokesman. He said he was unsure how long it takes for the sediment to dry. It was lowered by another two feet over the weekend.

The lake will return to the recreational depths by the opening of fishing season in early April.

Draw-down plans are created and approved by the Technical Drawdown Committee, which includes representatives from the Candlewood Lake Authority, U.S. Fish and Wildlife Service and the state Department of Energy and Environmental Protection.

“We do believe that the extreme cold weather will contribute to a successful draw-down and help to mitigate milfoil this summer,” Greene said.; 203-731-3345