FISHWAY POOL FLOOR 



OBSERVATION CHAMBER 



POOL 



POOL I 

 POOL] 



POOL 12 



SCALE 



METERS L. 



Figure 3. --Section of the l-on-16 slope endless flshway showing pool construction and location of observation 

 chamber. Each pool was 4.9 m. long, 0.9 m. wide, and 1.8 m. deep. Note level floors in flshway pools. 



TYPES OF FLOW EN FISHWAY 



Water for operation of the fishway came 

 from the forebay of Bonneville Dam. Forebay 

 levels at the dam fluctuated between elevations 

 of 22. 2 m. and 22.4 m. above mean sea level. 

 The level of the uppermost pool in the experi- 

 mental fishway was 20.4 m. and provided a 

 minimum operating head of 1.8 m. 



Plunging and streaming flows were produced 

 by adjustment of the valves that controlled 



volunne of flow and head on the weirs. The 

 head on the weir was defined as the difference 

 between the elevation of the weir crest and 

 the pool surface measured 0.9 m. upstream 

 from the weir. About 24.4 cm. was the nnaxi- 

 mum head at which a plunging flow could 

 be maintained. Increasing the head to 30.5 cm. 

 produced streaming flows in all fishway 

 pools. Average water depth in the pools was 

 2.07 to 2.13 m,, depending on the prevailing 

 flow. 



