Evaluation of the Eicher Screen at Elwha Dam: Spring 1990 Test Results

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Prepared for Electric Power Research Institute. http://www.epri.com


coho, descaling, Eicher screen, Elwha Dam, fish protection, hydroelectric, inclined screen, injuries, mortality, Penstock screen, prototype, screens, smolt, turbine bypass, water velocity, wedgewire screens

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Palo Alto, CA


Electric Power Research Institute


In the spring of 1990, the Electric Power Research Institute (EPRI) initiated testing of a prototype inclined penstock screen installed in a 9-foot diameter penstock at the Elwha Hydroelectric Project in Washington State. Results from the first series of tests showed that the screen effectively diverted coho smolts from the penstock with minimal injury. If results of future tests with other species are successful, the design concept has significant potential for application at other hydroelectric projects. The compact nature of the screen, which is designed to function at relatively high water velocities, is particularly suitable for retrofitting at projects where space limitations preclude installation of conventional screening systems. In the first series of tests conducted at the facility, over 99 percent of the coho smolts were diverted without mortality. At penstock velocities from 4 to 6 fps, less than 0.1 percent of the fish had scale loss exceeding 16 percent on either side (considered 'descaled' in criteria used on the Columbia River), and less than 5 percent showed any type of injury. Slightly more descaling was observed at higher penstock velocities. At the maximum velocity tested (7.8 fps), 3.6 percent of the fish had scale loss over 16 percent, and 18.1 percent of the fish has scale loss between 3 percent and 16 percent. Mortality after a 3- to 10-day holding period averaged 0.21 percent for test fish and 0.14 percent for controls. http://www.epri.com

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