Development of Turbine Intake Downstream Migrant Diversion Screen

Elder, Rex A.; Odgaard, A. Jacob; Weitkamp, Donald; Zeigler, Don; ,

Development of Turbine Intake Downstream Migrant Diversion Screen

by Rex A. Elder, Bechtel Civil & Mineral Inc, San, Francisco, CA, USA,
A. Jacob Odgaard, Bechtel Civil & Mineral Inc, San, Francisco, CA, USA,
Donald Weitkamp, Bechtel Civil & Mineral Inc, San, Francisco, CA, USA,
Don Zeigler, Bechtel Civil & Mineral Inc, San, Francisco, CA, USA,

Document Type: Proceeding Paper

Part of: Water Power '87

Abstract:

Prior to the spring of 1986 Public Utility District No. 2 of Grant County had developed a passive turbine intake screen design. A prototype of this design was placed in the emergency gate slot of the middle (B) bay of unit 9 turbine intake at the Priest Rapids Dam and tested in 1986. During the 1986 field tests a number of mechanical problems were resolved and sufficient information was obtained on its effect on fish passage to determine that the screen was diverting essentially all of the fish that were approaching the screened area. It was also found that descaling was occurring on about 30% of the smaller sockeye salmon. The data indicated that the injured fish may have been drawn against the diversion screen. To overcome the problems uncovered in 1986 it was decided to reduce the velocity through the diversion screen so that the smaller fish would not be drawn against the screen and injured. On a trial basis, a design was developed in the 1 to 16 model using perforated plate mounted on the downstream side of the diversion screen frame, leaving the bar screen used in 1986.

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