will virtually eliminate spilling at Columbia River dams. 

 All fish then will be forced to pass through the turbines. 



To assess the losses, fish were released through hoses 

 into intakes and passed through the turbines into specific 

 parts of the tailrace below the dam (figs. 37 and 38). Other 

 studies are underway to reduce these mortalities. Emphasis 

 is being placed on a plan that takes advantage of several 

 built-in structures of the dams. This method (developed 

 jointly by the Bureau of Commercial Fisheries and the U.S. 

 Army Corps of Engineers) calls for intercepting most of 

 the fish headed for turbine intakes and diverting them into 



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f-ii^ 





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FI(;i'HE :i7.— risli reliascd into turbines at Ice Harbor Dam 

 were collecled below the dam. Comparisons were made of 

 the survivals of fish that had passed through turbines and fish 

 that had bypassed the turbines. The hose in the foreground 

 carried the fish that were bypassed. 



FIGURE 36.-BIade of Kaplan turbine at Bonneville Dam. The 

 blade has thick edges, but fish arc injured where the clear- 

 ance between the turbine blade and the turbine wall is minimal. 



FIGURE 38.— Scoop (floating dipper) trap in operation to re- 

 cover fish from predator-laden water below a dam. 



— 28 — 



