Table 4. Distribution of passage times of individual ohinook salmon, sookeye salmon, and steelhead trout through 



0.3-m.- and 0.9-m. -diameter pipes at water velocity of 0.6 m.p.s., May-July 1963 



Time interval 



Spring ohinook salmon 



May 3 to 6 



0.3-m. 

 pipe 



0.9-m. 

 pipe 



Summer ohinook salmon 



June 13 to 16 



0.3-m. 

 pipe 



0.9-m. 

 pipe 



Sookeye salmon 



July 9 to 12 



0.3-m. 

 pipe 



0.9-m. 

 pipe 



Steelhead trout 



July 9 to 12 



0.3-m. 

 pipe 



0.9-m. 

 pipe 



Minutes 



Number of fish 



Number of fish 



Number of fish 



Number of fish 



0.0- 



2.0- 



4.0- 



6.0- 



8.0- 



10.0- 



12.0- 



14.0- 



16.0- 



18.0- 



20.0- 



22.0- 



24.0- 



26.0- 



28.0- 



30.0- 



32.0- 



34.0- 



35+.. 



1.9. 

 3.9. 

 5.9. 



7.9. 



9.9. 

 11.9. 

 13.9. 

 15.9. 

 17.9. 



19.9. 

 21.9. 

 23.9. 

 25.9. 

 27.9. 

 29.9. 

 31.9. 

 33.9. 

 34.9. 



4 

 16 

 5 

 2 

 1 

 2 



1 

 1 



4 

 11 

 3 

 1 

 2 



10 

 8 

 4 



2 



1 



3 



13 



4 



2 



1 



Total number of fish... 



Median (minutes) 



Lower limit median-'^. . . . 

 Upper limit median^.... 

 Percentage that completed 

 passage 



18 



24.2 

 7.2 



41.2 



56 



33 

 3.1 

 2.4 

 5.2 



100 



16 



10.6 



4.8 



34.8 



81 



25 

 3.3 

 2.1 

 5.4 



96 



11 

 9.4 

 2.5 



35+ 



73 



93 



80 



24 

 3.3 

 2.6 

 4.3 



96 



■"■ 95 percent confidence intervals about the median. 



the results in 1963 on fish passage through 

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

 pipes (table 4) indicated that fish were in- 

 fluenced by the size of the pipe opening. 



In 1964, truncated cones were placed at the 

 downstream entrance to the 0.3- and 0.6-m.- 

 diameter pipes to determine if this type of 

 structure would facilitate entry. The cone on 

 the 0.3-m. -diameter pipe tapered from 0.9 m. 

 to 0.3 m. and on the 0.6-m. -diameter pipe, 

 fronn 0.9-rn. to 0.6-m. Both cones were 3-m. 

 long and took up a greater part of the 4.3-m.- 

 long introductory pool. The pipes were not 

 illuminated except for a small amount of light 

 through the ends. 



The effect of a cone -type entrance on fish 

 passage through a pipe system was measured 

 by comparing passage times with and without 

 the cone. Two passage times were obtained-- 

 passage through the introductory pool and 

 passage through the pipe. Spring and summer 

 Chinook and sockeye salmon and steelhead 

 trout were examined in the 0.3- and 0.6-m. 

 pipe systems. 



In the 0.3-m. -diameter pipe system, salmon 

 and trout passed through the introductory pool 

 significantly faster when the cone was attached 

 (table 6). Passage times through the pipe with 



and without the cone did not differ significantly. 

 An additional advantage of the cone-shaped 

 entrance was indicated by the greater per- 

 centage of fish--particularly sockeye salmon 

 and steelhead trout-. that entered the pipe 

 within the 45-minute time limit (fig. 6). Per- 

 centages of fishthat completedpassage through 

 the introductory pool with and without the cone 

 were 100 and 60 percent, respectively, for 

 sockeye salmon and 100 and 82 percent for 

 steelhead trout. Percentages of spring and 

 summer chinook salmon that completed pas- 

 sage, however, increased only slightly when 

 the entrance cone was used. 



In the 0.6-m. -diameter pipe system, the 

 median passage time through the introductory 

 pool of the three species of test fish was 

 similar under both entrance conditions 

 (table 7), thus indicating that the cone did not 

 materially aid salmon and trout in entering the 

 pipe. The passage times of each fish through 

 the pipe section did not differ significantly 

 under the two entrance conditions. 



Illumination 



To determine if illumination inside the pipe 

 would improve conditions for fish passage. 



