The Entiat diversion weir, as shown in 

 figure 3, differs from the idealized structure 

 in that there are no abutments, and wooden "A" 

 frames have been substituted for steel . The 

 cost of materials for this 175 -foot weir when 

 it was installed in 1953 was $800. The installa- 

 tion itself was made by laboratory labor and 

 required 200 man hours. The entire yearly 

 maintenance cost including placement and re- 

 moval of electrodes for seasonal operation is 

 represented by less than 16 man hours of labor. 

 The electrical demand varies with the number 

 of electrodes submerged and the depth to which 

 they are submerged. At low water stages of 

 the river with approximately 32 feet of electrodes 

 submerged the demand was 300 watts. At med- 

 ium high water with 56 feet of electrodes sub- 

 merged, the demand was 450 watts . 



The power demand of the Entiat weir is 

 considerably less than that of the Great Lakes 

 weirs. This difference may be explained by 

 the lower conductivity of the stream bottom at 

 the Entiat weir site . Another contributing factor 

 to a lower power demand as the stream depth 

 increases, is the use of free swinging electrodes. 

 The water velocity through the weir varies from 

 3 feet per second at low water stages to 10 feet 

 per second at flood levels. As the depth of water 

 increases the length of submerged electrodes 

 does not increase accordingly because the cur- 

 rent velocity forces the lower ends of the 

 electrodes downstream and away from a vertical 

 position. In figure 4 the amount of deflection is 

 clearly demonstrated. Although the length of the 

 electrical field is shortened the strength of the 

 field is increased. No salmon has been able to 

 pass through the field at any water stage of the river. 







Figure 3 . - -The Entiat electrical weir looking upstream . Fish ladder to holding ponds 

 at upper left . Ground line may be seen on bank between electrode line and 

 fish ladder. 



