As central Maine’s summer remains drier than usual, lake management crews have limited flow through the Cobbosseecontee Lake Dam, leading water levels to drop downstream.

One resident who lives along the banks of Cobbosseecontee Stream — which flows from the lake through Litchfield and West Gardiner and into the Kennebec River in Gardiner — reported this weekend that water levels were so low that they were impacting aquatic life in the stream. Others have taken to social media to document low water levels.

Cobbossee Watershed District Limnologist Wendy Dennis said residents need not be concerned. The lone resident report about impact on fish has not been confirmed by the district, and water flow through the dam is above the state’s minimum limit, she said.

WHY ARE THE WATER LEVELS SO LOW?

Dennis said the water levels of every lake in the watershed, including Cobbosseecontee Lake, are low and still dropping. That’s not abnormal, she said.

“In a summer of average precipitation, you would just have gradual, minor declines in lake levels because you’re always going to lose water in the summer through evaporation — always,” Dennis said. “Evaporation takes inches of water off the lake, but you refill with precipitation. Even in an average-rainfall summer, there’s going to be lowering of lake levels.”

But the National Weather Service has recorded unseasonably little rainfall in central Maine this month, and high temperatures have regularly reached into the 90s — causing Cobbosseecontee Lake to be near its lowest level in the past couple summers.

So, Dennis said, beginning about a week ago, operators gradually slowed outflow from the dam, which is located on the eastern side of the lake near the intersection of Collins Road and Pond Road in Manchester. Dennis said dam operators have checked on the outflow at least twice per day since.

Now, water allowed through the dam has reached what Dennis said was “extremely low” outflow. Beyond the dam, water levels in Cobbosseecontee Stream have visibly dropped.

ARE THE LEVELS RELATED TO DAM REPAIRS?

No, Dennis said. Levels in Cobbosseecontee Stream are entirely unrelated to ongoing repairs at the Cobboseecontee Lake Dam; they’re only related to levels in the lake.

Dennis said the dam has two mechanisms to allow water through: boards and gates. As the gates were being repaired earlier this month, boards were lifted to allow water through. The same applies for the boards that Dennis said were being repaired this week.

WHAT ABOUT THE FISH?

Dennis said biologists in the Department of Inland Fisheries and Wildlife have set a minimum outflow of 21 cubic feet per second — the water equivalent of about 100 toilet flushes rushing over a particular point in one second — through the dam to ensure aquatic life downstream is unharmed.

The watershed district did receive one report from a nearby resident of “dying fish” in the low water levels, Dennis said, but that report has yet to be confirmed. She said the district welcomes reports of adverse impacts on aquatic life and takes them very seriously, but that there has been no evidence so far of fish in distress.

“If we get a verification from Inland Fisheries and Wildlife that there is a problem with fish, and if there’s something that they want done to rectify it, then we need to hear that from them, and we’re open to that,” Dennis said. “But right now, we are monitoring the situation closely, and we’re within where we think we should be.”

And even as levels in Cobboseecontee Lake continue to drop, she said water flow through the dam will continue to be well above that threshold.

“We won’t be going down to zero flow because of some lower water level in Cobbossee Lake,” Dennis said. “That won’t be happening.”

WHEN WAS THE LAST TIME THIS HAPPENED?

Dennis said the dam reducing outflow to this level is a relatively regular occurrence.

The dam last reached this low level of outflow for a couple weeks in June 2022, she said. Before then, it was June 2021, much of the summer in 2020, August 2019 and the late summer of 2018.

HOW LONG WILL THE REDUCED FLOW LAST?

At least until Cobbosseecontee Lake and the upstream lakes get substantial rainfall. The lake level must return to near normal before the stream can, Dennis said.