Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 5598
Title: Studies to evaluate the effectiveness of extended-length screens at The Dalles Dam, 1993
Author/Editor: Dean A. Brege, R. F. Absolon, Benjamin P. Sandford, Douglas B. Dey
Publication Year: 1994
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers. Portland, Oregon
Contract Number: E96930030
Pages: 72
Date: 1994
Abstract:

At The Dalles Dam in 1993, we evaluated fish guidance efficiency (FGE) of a prototype extended-length submersible bar screen and extended-length submersible traveling screen.   We also assessed the effects of these extended screens and other system components on fish condition.  Results from these evaluations were compared to concurrently obtained values with a standard traveling screen and are enumerated below.

  1. The extended-length bar screen produced significantly higher FGE than either the extended-length traveling screen or the standard traveling screen for yearling chinook salmon and steelhead.  The extended-length traveling screen produced significantly higher FGE than the standard traveling screen for yearling chinook salmon.
  2. Descaling rates were similar between extended-length bar and standard traveling screens for yearling chinook salmon and steelhead.
  3. Both descaling and FGE were significantly higher using the extended-length bar screen than the extended-length traveling screen or standard traveling screen for subyearling chinook salmon.
  4. Both descaling and FGE were significantly higher using the extended-length traveling screen than using the standard traveling screen for subyearling chinook salmon.
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