Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 7349
Title: Effects of flow and weir design on the behavior of American shad and salmonids in an experimental fish ladder
Author/Editor: Bruce H. Monk, Charles Richard Weaver, Clark S. Thompson, Frank J. Ossiander
Publication Year: 1986
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers. Portland, Oregon
Date: 1986

This research was conducted to determine methods of improving American shad (Alosa sapidissima) passage through flow control regulating sections of fish ladders at Columbia River dams without hindering the passage of anadromous salmonids, e.g., chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (O. nerka), and steelhead (Salmo gairdneri).  In 1969 and 1970, various weir configurations at two flow regimes were tested at the Fisheries Engineering and Research Laboratory located at Bonneville Dam on the Columbia River.  American shad passage through the test section was significantly increased when an overflow slot and submerged orifice were provided.  Velocities in the overflow slots were found to be critical to American shad passage.  Passage through the ladder system for the three species of salmonids tested was not adversely affected by the overflow slot.  Other tests were conducted in 1978 and 1979 at the same facility to determine the feasibility of using the American shad's preference for overflow slots to separate them from the salmonid species within the ladder system.