Northwest Fisheries Science Center

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Document Type: Report
Center: NWFSC
Document ID: 7305
Title: Survey of fish protective facilities at water withdrawal sites on the Snake and Columbia Rivers
Author/Editor: George A. Swan, T G. Withrow, Donn L. Park
Year: 1986
Institution: Internal report of the National Marine Fisheries Service, Northwest Fisheries Science Center. Seattle
Date: 1986

Proliferation of water withdrawals and new pump intake and screen designs has occurred with the growth of irrigated agriculture along the Columbia and Snake Rivers.  Concern for the protection of anadromous and resident fish populations resulted in formulation of a survey of the water withdrawal systems.  The survey included distribution studies of juvenile fish near pump sites and field inspection of those sites to determine adequacy of screening for protection of fish.  A total of 225 sites were inspected in 1979 and 1980, with a follow–up inspection of 95 sites in 1982.  Results indicated a definite trend toward lack of concern for the condition of fish protective facilities.  Only 4 out of 22 sites not meeting criteria in 1979 had been upgraded to acceptable conditions.  Of more concern, 13 of the sites meeting criteria in 1979 were below criteria when reinspected in 1982.  Some of the discrepancies included no protective screens, poorly maintained screens, and screens that permitted excessive velocity that could result in impingement of larvae or small fish.  A conclusion from these surveys is that if adequate protection for fish is to exist, screens for water withdrawals need to be properly installed, inspected, and maintained.