The Columbia Basin is the second largest river system in the U.S. and drains 260,000 square miles. Over a period of 70 years, roughly 400 dams and diversion structures have been built in the basin. Though the Federal Columbia River Power System provides irrigation water, flood mitigation, navigation and recreation, the system has critically affected a number of fish species, including: Chinook, coho, chum and sockeye salmon, steelhead, white sturgeon, lamprey and bull trout.
Some of the Columbia River Basin's endangered fish species migrate past as many as eight dams. Other challenges include predation, exposure to chemical contaminants or pathogens, reduced water quality, poor nutrition, injury, and the stresses associated with smoltification.
Within the Basin, the role of the U.S. Army Corps of Engineers’ role is to operate the hydropower system, in conjunction with other producers, in a manner that balances the needs of fish with other uses.