Biological Evaluation of a New Modular Fish Diversion Screen.

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Fish Passage Policy and Technology: Proceedings of a Symposium

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Bates K;


American Fisheries Society


The Electric Power Research Institute has developed and biologically evaluated a new type of fish diversion screen known as the Modular Inclined Screen (MIS). The MIS is designed to operate at any type of water intake with water velocities up to 3.05 m/s (10 fps). The biological evaluation of the MIS was conducted with juveniles of 11 species, including four resident freshwater species, two alosid species, and five salmonid species. Fish passage was evaluated at five module velocities ranging from 0.61 to 3.05 m/s (2-10 fps). Except for alosids, the percent of fish diverted live for each species exceeded 95% at all module velocities. Latent mortality (72-hour; adjusted for control mortality) rarely exceeded 2% at test velocities up to and including 2.44 m/s (8 fps). Net passage survival (percent diverted live adjusted for latent mortality) for all species tested (except alosids) was greater than 92.0% at module velocities of 2.44 m/s (8 fps) and less, and exceeded 99% overall for channel catfish Ictalurus punctatus, coho salmon Oncorhynchus kisutch, brown trout Salmo trutta, and Atlantic salmon Salmo salar. Fish passage tests with debris accumulation demonstrated that increases in screen head loss up to 12.2 cm (0.4 ft) did not reduce the ability of the MIS to safely and effectively divert fish, depending on species and module velocity.

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