FISHWAY CAPACITY 





In a pool-type fishway, "capacity" (i.e., tlie 

 maximum number of fish of a given size that a 

 fishway of specified design and dimensions can 

 pass per unit time) is controlled by the rate of fish 

 movement from pool to pool and the space re- 

 quired for each fish. Examples of laboratory 

 data on rates of movement for chinook salmon, 

 blueback salmon, and steelhead trout obtained 

 from a wide variety of experiments are shown in 

 table 1. Examination shows that although rates 

 vary with species and time of year there is 

 considerable consistency in the average rates of 

 movement under a wide range of experimental 



Figure 7. — The 4-foot wide, 1-on-16-slope fishway 

 used for fishway capacity tests. Passage of 3,000 

 salmonids per hour was demonstrated in this fishway. 



Table 1 . — Passage times per pool of individual and groups o( 

 salmonids oscending experimental fishways ' at Bonneville 

 laboratory 



Time per pool by species and source ^ of data 



' Pool-and-overfall-typc flshways with slopes of 1 on 8 and 1 on 16, varyinR in 

 width from 3 to 11.5 feet. No orifices in flshways, pool depth approximately 

 6.5 feet, rise between pools 1 foot and head on weirs 0.8 foot. Total rl.se varyins 

 from 6 to 6,600 feet. 



' See Appendix A. 





Figure 8. — The 16-pool, 1-on-8-slope endless fishway 

 nearing completion. Worker stands in fish entry 

 gate. Locking unit for lowering and recycling fish 

 appears in center. 



