The Crescent Lake dam is currently open about halfway in order to bring water levels in Lake Wentworth and Crescent Lake down about six to eight inches. The town is going to treat Back Bay with a chemical to kill the existing milfoil. Lowering the lake will provide a buffer against any sudden jump in lake levels that might be caused by weather in the second week of September. Too much water flowing into Back Bay could cause the milfoil treatment to be ineffective.
During the treatment period, which is expected to run from about September 8 or 9 to 15, the Crescent Lake dam will be completely closed in order to prevent currents from the Smith River from washing away the treatment chemicals. In past years, water coming into Back Bay from the Smith River has diminished the effectiveness of milfoil treatments. If another rain event like the recent one were to occur with the lake at “full” level, the amount of water going over the dam and entering Back Bay could cause the treatment to largely fail.
Questions about dam management can be addressed to Shaun Berry of Holden Shore.