AHSAHKA — Water managers from the Army Corps of Engineers will briefly increase flows leaving Dworshak Dam late this month.
According to a news release from the agency, flows will rise from about 1,700 cubic feet per second to a range of 4,000 to 6,000 cfs starting March 27 and stay elevated for about two days. The operation is expected to raise the elevation of the Clearwater River about 1.5 feet.
The increase in flows is part of an effort to make room for spring runoff in Dworshak Reservoir. Dworshak Dam is part of the federal government’s flood control system. Each year, water is evacuated before spring runoff. The reservoir is then able to reduce flooding potential by capturing water during the peak of runoff.
According to the news release, the operation starting later this month will allow the agency to release less water later and thereby help mitigate dissolved gas levels during the peak of runoff. Dissolved gas builds as water released through the dam’s spill gates plunges into the river below. When it reaches a certain level, it can be harmful to fish, including juvenile salmon and steelhead smolts beginning their migration to the Pacific Ocean.
According to the news release, the agency will continue to adjust the elevation of the reservoir next month by releasing water. Those releases will be based on snowpack measurements in the mountains that feed the North Fork of the Clearwater River.
On Thursday, the reservoir was 80 feet below full pool.