face of the screen); and 3) provide guidance to irrigators regarding efficacy and design 

 criteria of this alternative fish screen. 



LIST OF FEATURES 



A Inlet 



B Inlet pipe 



C Water surface In outlet water pipe 



D Fountain screen 



E Turt)ulent water on screen 



F Clean water through screen 



G Fish escapement from screen 



H Screened water outlet pipe 



I Corrugated metal pipe 



J Pipe rooting 



K Outer corrugated metal pipe 



L Bypass pipe with dsh 



Figure 54, Conceptual design of a turbulent fountain fish screen with bypass to stream. 



Methods 



In addition to hydraulic design criteria defined by Bondurant and Kemper (1985), 

 our prototype "fish screen" design incorporated a circular outer wall with an attached fish 

 bypass pipe (Figure 54), along with inflow and outflow capacity designed to maintain 

 constant flow through the bypass pipe. The screen was designed for a maximum inflow 

 of 0.14 m s, of which a maximum 0.085 m^s was available for outflow, with the 

 remainder available for the bypass. The screen incorporated a 1.25 mm mesh over a 1.68 

 m circular stainless screen set at a one percent slope, with a maximum mean approach 

 velocity of 0.122 meters-per-second over the surface of the screen. We also reduced the 

 screen diameter from the recommended original criteria of 213 cm to 152 cm in order to 

 more effectively wash fish and debris off the screen. Following construction, we 



87 



