Table 2 Distribution of passage times of individual ohinook salmon, sockeye salmon, and steelhead trout through 



82.3 m. of 0. 6-m. -diameter pipe at water velocities of 0.3, 0.6, and 0.9 m. p.s.; pipe system included two 180° 

 turns, April- July 1964 



-"- 95 percent confidence intervals about the median. 



passage times were significantly greater at 

 0.6 m.p.s. than at 0.3 m.p.s. (table 3). The 

 median passage time of summer chinook 

 salmon was also significantly greater at 0.15 

 m.p.s. than at 0.3 m.p.s. All of the spring 

 chinook salmon completed passage at 0.3 and 

 0.6 m.p.s. Percentages of summer chinook 

 salmon that completed passage ranged from 

 100 percent at 0.3 and 0.6 m.p.s. to 94 per- 

 cent at 0.15 m.p.s. 



Median passage times for sockeye salmon 

 at 0.15, 0.3, and 0.6 m.p.s. were 4.2, 2.6, and 

 3.4 minutes, respectively. The difference in 

 median passage times was statistically signif- 

 icant between 0.3 and 0,6 m.p.s. but not be- 

 tween 0.15 and 0.3 m.p.s. (table 3). Percentages 

 of sockeye salmon that completed passage 

 ranged from 99 percent at 0.3 m.p.s. to 100 

 percent at 0.15 and 0.6 m.p.s. 



Median passage times of steelhead trout 

 ranged from 2.2 minutes at 0.3 m.p.s. to 7.4 

 minutes at 0.6 m.p.s. Median passage times 

 at 0.15 and 0.6 m.p.s. were significantly greater 



than at 0.3 m.p.s. (table 3). Percentages of 

 steelhead trout that completed passage ranged 

 from 100 percent at 0.3 m.p.s. to 80 percent 

 at 0.6 m.p.s. 



Pipe Diameter 



The influence of pipe size was measured by 

 comparing the passage of chinook salmon, 

 sockeye salmon, and steelhead trout through 

 equal lengths of 0.3- and 0.9-m. -diameter 

 pipes under identical flow conditions (water 

 velocity of 0.6 m.p.s.). All three species per- 

 formed better in the 0.9-m. pipe than in the 

 0.3-m. -diameter pipe (table 4). 



Median passage times through the 0.3- and 

 0.9-m. pipes were 24.2 and 3,1 minutes for 

 spring chinook salmon and 10.6 and 3.3 minutes 

 for summer chinook salmon. In both tests the 

 median passage times through the 0.3-m. pipe 

 were significantly greater than through the 

 0.9-m. pipe. Percentages that completed pas- 

 sage through the 0.3-''and 0.9-m. pipes ranged 



