EFFECTS OF VARIOUS FACTORS 

 ON FISH PASSAGE 



These tests indicated that, if conditions are 

 acceptable, adult salmon and trout enter and 

 pass through pipes. The efficiency of a pipe 

 as a passageway, however, may be influenced 

 by such factors as water velocity, pipe di- 

 ameter, entrance and exit conditions, illumi- 

 nation, pipe configuration, and water depth. The 

 influences of these factors on fish passage are 

 discussed in the following sections. 



Water Velocity 



Tests that measured the effect of water 

 velocity on the passage of spring and sum- 

 mer Chinook salmon, sockeye salmon, and 

 steelhead trout were made in the 0.3- and 

 0.9-m. -diameter pipes in 1963 and in the 

 0.6-m. -diameter pipe in 1964. Water veloci- 

 ties were 0.15 to 1.2 m.p.s. 



Velocities in 0.3-m. -diameter pipe . --Fish 

 were tested in water velocities of 0.3 to 1.2 

 m.p.s. in the 0.3-m. -diameter pipe. Summer 

 Chinook salmon were tested in velocities of 

 0.6 and 1.2 m.p.s. 



These tests showed that the entry and pas- 

 sage of fish through the 0.3-m. -diameter pipe 

 was influenced by velocity. Spring and summer 

 Chinook and sockeye salmon entered and moved 

 more quickly at 1,2 m.p.s. than at other velo- 

 cities, but steelhead trout performed best at 

 0.6 m.p.s. (table 1). 



We began the tests with spring chinook salmon 

 at velocities of 0.3, 0,6, and 1,2 m.p,s, in the 

 0.3-m. pipe in 1963, The first tests at 0.3 

 m.p.s. demonstrated that this flow was not 

 strong enough to induce fish passage; thus no 

 further tests were made at this velocity during 

 the spring or sunnmer chinook salmon run. 

 Later in the season, however, the 0.3 m.p.s. 

 velocity was applied in tests with sockeye 

 salmon and steelhead trout. 



Median times required by spring chinook 

 salmon to complete passage at velocities of 

 1.2, 0.6, and 0.3 m.p.s. were over 9, 15, and 

 35 minutes, respectively. Medianpassage time 

 at 0.6 m.p.s. was significantly greater than at 

 1.2 m.p.s. Percentages of spring chinook sal- 

 nnon that completed passage ranged from 89 

 percent at 1.2 m.p.s, to 14 percent at 0.3 nn.p.s. 



The performance of summer chinook salmon 

 was similar to that of spring chinook salmon 

 in that the median passage time at 0.6 m.p.s. 

 was significantly greater than at 1.2 m.p.s. 

 (table 1). Percentages of chinook salmon that 

 completed passage under the two conditions 

 were 61 and 93 percent, respectively. 



Median passage times of sockeye salmon 

 ranged from 6,9 minutes at 1,2 nn.p,s, to over 

 35 minutes at 0.3 m.p.s. (table 1). The median 

 passage time at 0,3 m.p.s, was significantly 

 greater than at either 0,6 or 1,2 m.p.s. Per- 

 centages of sockeye salmon that completed 

 passage ranged from 92 percent at 1.2 m.p.s, 

 to 46 percent at 0.3 m.p.s. 



Median passage times for steelhead trout 

 at 0.3, 0.6, and 1.2 m.p.s. were 19.6, 3.4, and 

 10.9 minutes, respectively (table 1). Median 

 passage times at 0.3 and 1,2 nn.p.s. were 

 significantly greater than at 0.6 m,p,s. Per- 

 centages of steelhead trout that completed 

 passage ranged from 97 percent at 0,6 m,p,s, 

 to 54 percent at 0,3 m,p,s. 



Velocities in 0.6-m. -diameter pipe . --Water 

 velocities in 1964 were 0.3 to 0.9 m.p.s. in the 

 0.6-m. -diameter, 82.3-m.-long pipe. Summer 

 chinook salmon were tested at velocities of 0.3 

 and 0,9 m.p.s. and spring chinook salmon, 

 sockeye salmon, and steelhead trout, at 0,3, 

 0.6, and 0.9 nn.p.s. 



Fish passage in the 0.6-nn. -diameter pipe 

 did not vary greatly in relation to water veloc- 

 ity. Chinook and sockeye salmon performed 

 slightly better at 0.9 nn.p.s., whereas steel- 

 head trout performed best at 0.6 nn,p,s. 



Median passage times of spring and sunnmer 

 chinook salnnon ranged from 7,8 minutes at 

 0,9 m,p,s. to 10.6 minutes at 0.3 m.p.s, (table 

 2). Percentages of spring chinook salmon that 

 completed passage through the 82.3-m. pipe 

 ranged from 89 to 78 percent at the three 

 velocities. Percentages of sunnnner chinook 

 salmon that connpleted passage were 88 and 87 

 percent at 0.3 and 0.9 m.p.s., respectively. 



Passage tinnes of sockeye salmon at the 

 three water velocities were 6,3, 7,5, and 6.4 

 minutes. Percentages of sockeye salmon that 

 completed passage ranged from 96 percent at 

 0.9 nn.p.s. to 84 percent at 0.6 m.p.s. 



Median passage times for steelhead trout 

 at 0,3, 0.6, and 0,9 m,p,s, were 16,1, 16,0, 

 and 29.7 minutes, respectively. The difference 

 between the nnedian passage times at 0.6 and 

 0,9 m,p.s. was significant but not that between 

 0,6 and 0,3 m.p.s. or 0.9 and 0.3 m.p.s. (table 

 2). Percentages of steelhead trout that conn- 

 pleted passage at the three velocities ranged 

 from 79 percent at 0.6 nn.p.s. to 59 percent 

 at 0.9 m.p.s. 



Velocities in 0.9-nn. -diameter pipe . --Water 

 velocities from 0.15 to 0.6 m.p.s. were tested 

 in 1963 in the 0.9-nn. -diameter pipe. Spring 

 chinook salmon were tested at velocities of 

 0,3 and 0,6 m,p.s. and sunnmer chinook salmon, 

 sockeye salmon, and steelhead trout at 0,15, 

 0.3, and 0.6 m.p.s. 



Individual salmon and steelhead trout en- 

 tered and passed through the 0.9-m. pipe at 

 all the velocities, but their best perfornnance 

 usually was at 0,3 nn,p,s, (table 3), Differences 

 between the fastest and slowest median passage 

 tinnes ranged from 2 to 4.2 minutes for salnnon 

 and fronn 2.2 to 7.4 nninutes for steelhead 

 trout. Although the differences between nnedian 

 passage times at some velocities were sta- 

 tistically significant, the difference was snnall 

 when the distance traveled (35.4 nn.) is con- 

 sidered. 



Responses of spring and sumnner chinook 

 salmon were similar in that their median 



