Spokane River flows from behind the Post Falls Dam will drop to the minimum of 500 cubic feet per second this weekend or early next week.
Officials at Avista Corp., which operates the dam, said the lower flows will help maintain the level of Lake Coeur d’Alene and keep water in the river through the rest of the summer.
The flow levels are dictated by a federal license that governs operations of the utility’s dams on the Spokane River. The license was reissued in 2009. It balances lake levels and downstream flows, taking into account fish habitat, water quality and public recreation.
Poor snowpack, along with hot, dry weather, has reduced water levels in both the lake and the river this year. Agencies, including Idaho Department of Environmental Quality and the Washington Department of Ecology, are encouraging people to conserve water to reduce pumping from the Spokane Valley-Rathdrum Prairie Aquifer.
“In dry years like this, the connection between the aquifer and the river becomes quite clear,” said Guy Gregory, a senior hydrogeologist for the Ecology Department. “Water use by people directly affects river flows. That’s why we hope people will use water wisely and efficiently. Fix a leak, don’t water the sidewalk and pay attention to how much you irrigate. It matters.”