June 15,2010 - Maine dam removal: Lower Montsweag Brook Dam

Two Maine dam removal projects recently won funding from nonprofit conservation organization American Rivers and the U.S. Commerce Department’s National Oceanic and Atmospheric Administration Restoration Program. The Maine Council of the Atlantic Salmon Federation won $65,000 to remove the West Winterport Dam on Marsh Stream, a Penobscot River tributary, in Winterport and Frankfort, which will open up 4.5 miles of the stream and restore 20 miles of river habitat.

The other grant was $100,000 to the Chewonki Foundation for the removal of the Lower Montsweag Brook Dam near Wiscasset and Woolwich. This removal will reopen three miles of fish passage and restore the 20 acres of riverine habitat currently flooded by the dam.

Lower Montsweag Brook Dam (map) was constructed by Maine Yankee Atomic Power Company in 1968. The purpose of the 30' tall dam was to impound a backup supply of emergency water for Maine Yankee's nuclear power plant operations.

Chewonki acquired the dam as part of the 2008 Natural Resources Damages Restoration Plan and Settlement Agreement (NRDAR) between Maine Yankee and the State of Maine. As part of that settlement, Chewonki committed to evaluate alternatives for restoring fish passage and riparian habitat in the lower brook.

A feasibility study by Stantec Consulting, Inc., of Topsham, showed that removal of the concrete dam is the most effective and least expensive way to restore fish passage for fish species such as river herring, rainbow smelt, brook trout, and American eel.

Chewonki plans to remove the dam later this summer at a cost of $750,000 to $800,000. A slow drawdown of the impoundment was scheduled to begin in May. This drawdown will allow contractors to inspect the upstream face of the dam and to begin revegetating the impoundment area. Demolition activities will be scheduled to coincide with the low stream flow period of late summer.