Sometimes being underwater is a good thing, especially for Columbia River salmon nests, called redds. This fall, federal agencies are increasing Columbia River flows below Bonneville Dam to ensure the redds of spawning chum salmon stay covered with water. The agencies have conducted these “chum operations” every fall since 2000.
Beginning Nov. 2, the river will be held between 11.5 to 13 feet above sea level to ensure chum can spawn at the mouth of Hamilton Creek in the Columbia River Gorge. For chum operations to occur, water is released from reservoirs as far away as Hungry Horse and Libby dams in Montana, more than 850 river-miles upriver from Bonneville Dam. The water is then captured and released as needed to create spawning flows that keep the redds underwater.