A channel at the Thompson Lake dam in Oxford carries water into the Little Androcoggin River. A gate on the dam will be replaced this month, necessitating drawing down water in the lake. Submitted photo

OXFORD — Officials will begin drawing down the water level of Thompson Lake on Tuesday to prepare for repairing the dam at the outlet into Little Androscoggin River this month.

The 8-mile-long lake extends from Oxford south through Otisfield, Poland and Casco. About 40% of the shoreland is in Oxford.

Oxford Town Manager Butch Asselin suggested that starting Tuesday, watercraft owners start monitoring water levels daily and make arrangements to get their boats out earlier than usual.

“Water levels will decrease to 33 inches below the dam benchmark line, which is what it is typically seen during the winter months,” he said. It is about 20 inches below the benchmark line now.

The winter drawdown is usually done around Columbus Day in October.

“In order to take advantage of warmer temperatures within a short construction window, we decided to start the project in September,” Asselin said in a statement. “The drawdown is necessary for cofferdam placement and to put the town in compliance with the Natural Resources Protection Act permit.”

A cofferdam is a watertight enclosure pumped dry to permit construction work below the waterline.

Bancroft Contracting of South Paris will start cofferdam installation Sept. 14 and replace the dam’s nonfunctioning east gate and do other maintenance. The project, estimated to cost about $500,000, is expected to be completed before the end of the year.

Asselin said further information on the dam project and water levels is available by contacting municipal officials in the four towns.

According to the Thompson Lake Environmental Association website, the dam was built in 1863 by Joseph Robinson, owner of Robinson woolen mill that operated at the site. The dam remained in the Robinson family for almost 150 years until the town took ownership and management of it in 2010.

The dam, after years of neglect, will require multiple, scheduled repairs and maintenance work.

It also has been the target of criminal mischief recently. Earlier this year, vandals unsuccessfully tried to remove stop logs of the east gate. Two weeks ago, vandals pulled up stop logs on the west gate, which caused the water level to drop 3 inches below normal. A nearby building was also painted with graffiti.

“If the east gate logs had been removed, it could have begun an unstoppable drain of the lake,” Asselin said. “We’ve added flood lights and security cameras. Bancroft is aware of the incidents and the Oxford Police Department will increase patrol of the mill going forward.”


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