OXFORD — The Board of Selectmen agreed Thursday night to host a joint public hearing with the Thompson Lake Environmental Association on the need to lower the level of Thompson Lake each October to prevent spring flooding.

The Dam Advisory Committee, which includes members from Casco, Oxford, Poland and Otisfield, recommended a public hearing on the matter during its Tuesday meeting.

Scott Bernardy, environmental chairman for the TLEA, spoke at both meetings on the need to prevent flooding, which erodes phosphate-rich soil into the lake and fuels the growth of water-clouding algae.

The dam at the former Robinson woolen mill is used to keep the water level in an optimal range called the cobble zone, which is mostly made up of stone and where erosion is minimal.

A steering committee analyzed 20 years of recorded water levels between 1966 and 1986 and determined the average winter water level to be 37 inches below the top of the dam.

In recent years, the level has been much higher, resulting in spring flooding and erosion. The TLEA recommends a water level of 32 inches below the top of the dam, which would be set in October after most lake activity is done.

The meeting will also discuss dam upkeep and Bernardy’s recommendation of shortening spillway planks on the dam by two inches, so that rain storms don’t raise the lake level above 14 inches from the top of the dam.

Town Manager Michael Chammings warned that the water level can be a contentious topic for people living on Thompson Lake. He said that during droughts, he gets calls from angry property owners about the water being too low. Chammings suggested a public hearing to explain the problem and said residents may have some good ideas on dam maintenance.

The TLEA will be contacting people living along the edge of the lake. A date hasn’t been set for the public hearing, but Chammings suggested the Thursday before Labor Day. The dam committee will set the meeting date at its Aug. 14 meeting.

treaves@sunjournal.com

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