Effects of bypass system passage at Bonneville Dam second powerhouse on downstream migrant salmon and steelhead : direct capture assessment, 1990-1992

Passage survival tests at Bonneville Dam using coded-wire-tagged subyearling chinook salmon, from 1987 to 1992, indicated substantially poorer survival for fish using the bypass systems than other passage routes through the dam. In 1990, we began research designed to identify conditions and physical features of the bypass system at the Bonneville Dam Second Powerhouse which debilitated or injured juvenile salmonids during passage. Marked fish were released into the bypass system and then captured at the terminus of the discharge conduit using a trap-net. Contract no. DACW57-85-H-0001