Thaw runoff forces utility to level flows
The huge runoff from recent thaw prompted Avista Utilities to open all of its spill gates at Post Falls Dam on Wednesday
The utility also canceled a planned drawdown of the reservoir behind Long Lake Dam because of high flows in the Coeur d’Alene and St. Joe rivers and a higher pool in Lake Coeur d’Alene. The 14-foot drawdown was intended to help control invasive Eurasian milfoil and allow property owners to perform shoreline work.
Lake Coeur d’Alene was roughly 2 feet above its summer full-pool elevation of 2,128 feet Wednesday, and river flows in downtown Spokane reached 21,000 cubic feet per second.
Dam operators are working to keep the Long Lake reservoir slightly below full pool to help prevent flooding near the confluence of the Little Spokane River and the reservoir. As flows decrease, Avista plans to bring Long Lake up near summer full-pool levels. Weather conditions will dictate whether the utility reschedules the drawdown.
Farther north, the U.S. Army Corps of Engineers released more water through Albeni Falls Dam to maintain a steady elevation in Lake Pend Oreille. Releases through the dam are expected to continue through the weekend.