Table 8. — Distribution of passage times of individual ohinook salmon, sockeye salmon, ooho salmon, and steelhead 

 trout through a 0.6-m. -diameter pipe 82.3 m. long under illuminated and nonilluminated conditions; the pipe 

 system included two 180° turns, and water velocity was 0.9 m.p.s., June-September 196^ 



■"■ 95 percent confidence intervals about the median. 



Median passage time of fall chinook salmon 

 through the pipe was 19.2 minutes under the 

 flooded condition and 7.1 minutes under the 

 partly filled condition. This difference, although 

 fairly large, was not statistically signifi- 

 cant. Percentages of chinook salmon that 

 completed passage were 73 in the full pipe 

 and 85 in the partly full pipe. Median passage 

 time of steelhead trout through the partly 

 filled pipe was significantly faster than through 

 the flooded pipe (13.3 and 30.2 minutes, re- 

 spectively). Percentages of steelhead trout 



that completed passage were 100 percent in the 

 partly full pipe and 71 percent in the flooded 

 pipe. 



Tests in the 27.4-m. straight section of pipe 

 (table 11) gave results somewhat similar to 

 those in the 82.3-m. pipe, except that fall 

 chinook salmon showed no evidence of moving 

 faster when the pipe was partly full. 



Median passage times of chinook salmon 

 through the straight pipe were 1.3 minutes in 

 the partly full and 1.2 minutes in the flooded 

 pipe. The percentage of chinook salmon that 



13 



