Biological design criteria for improved wet-separator efficiency and high-velocity flume development, 1997

During the 1997 spring and summer juvenile salmonid outmigrations, we continued research to provide biological design criteria for the improvement of wet separators used in fish passage facilities at hydroelectric dams on the Snake and Columbia Rivers. In addition, we conducted evaluations to develop new concepts in juvenile salmonid wet separation. Two evaluation separator units were used to trap river-run smolts from Gatewell 6B at McNary Dam: a unit simulating an existing conventional wet separator and an experimental high-velocity flume (HVF) separator. In the simulated conventional wet separator, we compared six treatments consisting of different on/off combinations ofspray bars, light stripes added to darker-colored separation bars, and a reverse flow orifice. Evaluation criteria were salmonid separation efficiency, separator exit efficiency, and descaling. No significant differences in separation efficiency, separator exit efficiency, or descaling were found among the six on/off treatments evaluated using the simulated conventional wet separator. Contract no. E86910060