40 



30 



M 

 Q> 



3 

 C 



-£ 20 



E 



10 



© 



^(203fish) 



8-30-56 

 (255 fish) 



f^ 8-21-56 

 ^(291 fish) 



X 



I 2 



Rise between pools in feet 



with a 1.0-foot rise between pools than 

 in the l:16-slope fishway with a 1.0-foot 

 rise between pools. No significant dif- 

 ference was found in the passage times 

 of steelhead in the l:8-slope fishway with 

 a 1.5-foot rise between pools and in the 

 l:l6-slope fishway with a 1.0-foot rise 

 between pools. No significant difference 

 was found in the passage time of steel- 

 head in the l:8-slope fishway with a 2.0- 

 foot rise between pools and in the 1:16- 

 slope fishway with a 1.0-foot rise between 

 pools but observations indicate the test 

 fishway was more difficult to ascend. 



Chinook salmon appeared to be slower 

 in the l:8-slope fishway with a 1.5 -foot 

 rise between pools than in the 1:16- slope 

 fishway with a 1.0-foot rise between pools. 

 Further studies are necessary before any 

 clear-cut conclusions can be drawn with 

 respect to chinook salmon passage in the 

 1: 8- slope fishway. 



Using time per pool as an index of 

 fatigue, no tiring effect could be shown 

 for chinook salmon and steelhead as they 

 ascended either fishway. 



Figure 10.- -Comparison of fish ascent (groups of mixed species) 

 in tiiree variations of a l:8-slope fishway. Ascent plotted as 

 median elapsed time to complete a total rise of 6 feet. 



Further evidence is found by com- 

 paring passage times of groups of steel- 

 head in the l:8-slope fishway. The nnean 

 time of 12 groups of 20 steelhead was 

 10.21 minutes in the fishway with a 1.0- 

 foot rise between pools and 14.28 minutes 

 with a 2.0-foot rise between pools. 



No difference could be shown between 

 median elapsed times of steelhead timed 

 in the morning and in the afternoon. 



In the I:16-slope fishway, the rate of 

 passage of steelhead decreased during the 

 season, the earlier part of the run being 

 faster. 



In the l:8-slope fishway there was a 

 suggested direct relationship between pas- 

 sage time of groups of mixed species and 

 the rise between pools. 



SUMMARY 



The effect of fishway slope on the 

 rate of passage of salmonids was studied 

 at the Fisheries-Engineering Research 

 Laboratory at Bonneville Dam by com- 

 paring passage tinnes of fish in a l:8-slope 

 fishway with passage times in a conven- 

 tional l:l6-slope fishway. Both fishways 

 were short segnnents of pool-type fishways 

 without submerged orifices. There was a 

 6-foot gain in elevation to each fishway. 



Steelhead passage times were signifi- 

 cantly shorter in the l:8-slope fishway 



LITERATURE CITED 



DIXON, WILFRID J., AND FRANK J. MAS- 

 SEY, JR. 

 1951. Introduction to statistical analy- 

 sis. First edition. New York, Mc- 

 Graw-Hill Book Company, 370 pages. 



ELLING, CARL H., AND HOWARD L.RAY- 

 MOND. 

 1959. Fishway capacity experiment, 

 1956. U.S. Fish and Wildlife Serv- 

 ice, Special Scientific Report- -Fish- 

 eries No. 299, 26 pp. 



11 



BCF No. ei2. 



