ABSTRACT 



An electrical weir consisting of a line of hanging electrodes and a 

 submerged ground line has proved satisfactory for the diversion of adult 

 salmon. The electrical field is created by 110-volt, single phase, 60-cycle, 

 alternating electrical current available from most commercial sources . 



TTie optimum operating conditions for a weir of this type require 

 minimum stream velocity within the electrical field of 3 feet per second, 

 minimum barrier voltage of 0.5 volts per inch, and minimum field length 

 of 10 feet with a voltage gradient which may vary within the range of from 

 0.3 to 0.7 volts per inch in the effective field. 



Adult salmon, once conditioned to the electrical stimulus, may be 

 diverted from their normal migration path into an alternate route by the electric- 

 al field. With adequate water velocities and voltage gradients the electrical weir 

 is a positive barrier to the upstream migration of adult fish. Downstream 

 migrant salmon fingerlings pass through the weir with impunity. 



The weir is generally applicable to the varying conditions encountered 

 in salmon streams of the Pacific Coast. 



