Dworshak Reservoir Starts
The annual lowering of Dworshak Reservoir started early this year in anticipation of a heat wave forecast to deliver a string of days with temperatures in the triple digits.
The Army Corps of Engineers began ramping up flows leaving Dworshak Dam on Tuesday night and continued through Wednesday, with a goal of getting to 12,400 cubic feet per second.
Each year, 43-degree water is released from deep below the reservoir's surface in an effort to mitigate temperatures in the lower Snake River. The cooler water travels down the Clearwater River and joins the Snake River at Lewiston. The releases are designed to help both adult and juvenile salmon and steelhead during their migrations to and from the ocean.
The Corps, working with state, federal and tribal fisheries managers, attempts to keep the river from exceeding 68 degrees at Lower Granite Dam. Temperatures in the 70s can be harmful to the fish, some of which are listed as threatened or endangered under the Endangered Species Act.
Water at the Anatone gauge south of Asotin was nearly 70 degrees Wednesday and 65 degrees at Lower Granite Dam.
The Corps usually waits until after the Fourth of July holiday to begin releasing the water and usually starts with the elevation at full pool. This year, the reservoir reached an elevation of 1,597 feet, or 3 feet below full pool, before the releases began. The releases typically last into mid-September and result in the reservoir reaching an elevation of 80 feet below full pool.
Cold Water Released from North Idaho Dam to Help Salmon by Associated Press, The Olympian, 6/25/21
Dworshak Flows Increase; Clearwater Level Expected to Rise by Staff, Lewiston Tribune, 5/23/19
Agency Plans to Cut Dworshak Reservoir Water Flows Today by Staff, Lewiston Tribune, 4/6/19
Clearwater River Level to Drop a Foot Below Dworshak; Dam Outflows Reduced for Juvenile Fish by Staff, Daily Fly, 7/19/18
Corps Reduces Dworshak Flows for Fish by Eric Barker, Lewiston Tribune, 3/27/18
Dworshak Dam Tests May Cause River Flow Changes by Staff, Lewiston Tribune, 6/28/18
Rehab of Dworshak's Unit 3 Has its Share of Hiccups by Elizabeth Morgan, Clearwater Tribune, 8/16/17
Dworshak Dam Discharge Flows Lowered to Reduce Flooding Impacts Downstream by Mia Carlson, Daily Fly, 3/20/17
Dworshak Reservoir Filling Up Early by Associated Press, KTVB, 4/26/15
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