148 



Snike RIvc 



Sp 



Spill as a recovery action 



Spill is used to pass fish over dams. This reduces total mortality in dam 

 passage since mortality resulting in passage by spill is less than passage 

 resulting through turbine passage. 



Tailwater 



Bypass 



Turbine 



Spill also produces gas supersaturation in the water downstream of dams. Fish 

 exposed to the supersaturation suffer some additional mortality from gas 

 bubble trauma. The amount of mortality depends on: 



•level of gas supersaturation 



•length of time fish are exposed to supersaturation 



• depth of fish in the reservoir 



Jemes ArxJonon 

 UnlverEiTy of Wathlngion 



