The rivers of the Pacific Coast states are heavily altered by dams and diversions ( over 1,400 dams in California, 1,039 in Oregon, 1,174 in Washington ). The dams generally are used for hydropower generation, irrigation, and transportation, all essential to supporting the region’s extensive agricultural and manufacturing (aluminum, aircraft, shipbuilding) industries. Dams create problems for fish such as salmon and steelhead by interrupting or halting their migration from the Pacific to upstream habitats and killing large numbers of young salmon (smolts) as they move downstream through powerhouses or spillways. Numbers of salmon and steelhead have declined drastically from historic levels, and many populations are listed as threatened [...]
