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Ecology and salmon related articles

Dworshak Full, for Now

by Staff
Lewiston Tribune, June 29, 2012

Dworshak backs up the North Fork of the Clearwater River, which flows into the Clearwater, the Snake and then the Columbia River. Those rivers hold both hatchery fish and wild stocks that are protected under the Endangered Species Act. Dworshak Reservoir is full or nearly so and will stay that way through at least Wednesday. But officials say water levels will start dropping during the second week of July if not sooner.

Steve Hall, water manager for the Walla Walla district of the U.S. Army Corp of Engineers, said the reservoir should reach its official "full" elevation of 1,600 feet in the next few days. The elevation this afternoon is 1,599.6.

"The intent is to, once it does hit 1,600, pick a flat (out) flow we think we can old through the Fourth of July. Right now temperature modeling is showing we shouldn't have any immediate issues with water temperature below Lower Granite Dam."

Each summer, about 1 million acre feet of water from Dworshak is used to both cool the lower Snake River and to increase its velocity with the aim of helping threatened juvenile fall chinook during their migration to the ocean. The cool water also helps returning adult steelhead.

But the draw down that is called for in the biological opinion that guides management of Snake and Columbia river dams, lowers Dworshak by 80 feet. The dropping water cuts short the recreation season on the man-made lake. Those who like to camp on the reservoir often target early and mid July as the best time. By late July or August, the water level is often 20 or more feet below full pool and the muddy ring between the water and camping spots becomes difficult to negotiate.

Hall said even if region temperatures remain mild in the next week, salmon managers are likely to soon ask for increased flows to help speed the young fish through the hydro-system.

"We will have to crank up the flow as we reach the 9th or 10th (of July) and then go from there," said Hall.

So now is the time to hit the reservoir and see it brim full.

Dworshak Full, for Now
Lewiston Tribune, June 29, 2012

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