SEATTLE – The U.S. Army Corps of Engineers has two flood teams out in northern Idaho and has completed levee strengthening work in central Washington near Naches.
The Coeur d'Alene basin team is finishing work with Bonner County to stabilize an eroding outfall structure/access road at Cocolalla Lake near Sagle, Idaho. The Yakima basin flood team completed work to strengthen the McCormick Levee on the Naches River near the town of Naches. Flood teams are monitoring conditions and providing technical assistance in the St. Joe and Coeur D’Alene river basins. The Corps provided a pump to the town of Cataldo, Idaho, which is pumping to reduce flood risk there. The Coeur d’Alene team also provided sandbag training April 25 at Harbor Island.
In addition, the Corps is operating its reservoirs to reduce flood risk. With flows from tributaries downstream from Libby Dam receding, outflows from the dam were increased from 9,000 cubic feet per second to 13,400 cfs as the flood risk from local inflows decreased in Bonners Ferry, Idaho. Inflows to Libby Dam exceeded 48,000 cfs during this storm.
At Albeni Falls Dam, the powerhouse was taken offline and the spillway gates were raised April 24, transitioning to a free-flow operation. The normal maximum elevation for April on Lake Pend Oreille is 2,056 feet and the corresponding channel capacity at the lake limits outflows to 56,000 cfs. Since inflows are now exceeding 80,000 cfs, switching to free-flow operations allows the Corps to keep the lake level as low as possible in April.
Under this operation, outflow from Albeni Falls was approaching 70,000 cfs this afternoon and is increasing gradually as the lake level rises. The current elevation of Lake Pend Oreille, as measured at Hope gauge, is 2,057.6 feet.
The Corps’ emergency operations center is under 24-hour operation and the reservoir control center is continually monitoring conditions. Additional volunteer flood fight team members and reservoir managers at the Corps’ Seattle District remain on alert and poised to respond as necessary to areas affected by flooding.
Current flow information for many of the river basins in the Northwest may be found here:
http://www.nwd-wc.usace.army.mil/nws/hh/index-j.html