Evaluation of extended-length submersible bar screens at Bonneville Dam First Powerhouse, 2000

Submersible traveling screens (STSs) are installed in all turbine units at Bonneville Dam First Powerhouse to guide juvenile salmonid migrants into a juvenile fish bypass system. In tests conducted from 1989 to 1992, fish guidance efficiency (FGE) ofthese screens ranged from approximately 40% for yearling chinook salmon to 60% for coho salmon and steelhead during the spring migrations. During the same testing period, FGE for sockeye salmon was approximately 25%. During the summer migrations, FGE for subyearling chinook salmon was approximately 40% in June, then decreased to less than 10% by the second week in July. Contract no. W66QKZ80545753