Biological Evaluation of Angled-screen Test Facility

A three-year study sponsored by the Empire State Electric Energy Research Corporation was conducted to determine the diversion efficiency and survival of adult and larval fish at a full-scale angled screen demonstration facility located on the Hudson River estuary. A total of 59,309 fish were collected during the three-year study, 99.4% from the diversion flow. Initial survival was 90.2%. Extended survival following a 96-hr observation period was 35.3%. The angled-screen system efficiency was 31.6%, increasing to 84.3% when corrected for collection and handling mortality. Ichthyoplankton diversion efficiency of 16.3% was inversely related to angled screen approach velocity and directly related to the size of the organism. Angled-screen system efficiency for ichthyoplankton was 1.7%. The angled-screen was judged to be successful for mitigating fish impingement. Ichthyoplankton study results indicate low diversion and high mortality, suggesting that angled screens are not effective for mitigating entrainment.