Table 10. --Percent of different species using 

 weir overfalls and orifices at weir 60 dur- 

 ing two group releases, June 29 and July 6, 

 1960 



of the fishway. There are two 18-inch square 

 orifices in each weir located on the floor and 

 adjacent to the sides of the fishway. 



Passage times of chinook salmon, sockeye 

 salmon, and steelhead trout were used to 

 assess performance of fish under various 

 operational conditions in the test fishway sec- 

 tion. A divider panel, inserted in the center 

 of each pool, pernnitted sinnultaneous testing 

 of the effects of various fishway modifications 

 on the performance of fish. Comparisons of 

 the performance of fish under half-width (8 

 feet wide) and full-width fishway (16 feet wide) 

 conditions were also made. Results of these 

 tests, when compared with similar data from 

 previous tests in a 1 -on- l6-slope fishway. 



provided a preliminary basis for evaluating 

 the ne'w fishway design. 



Flow patterns and velocity profiles were 

 obtained under normal and experimental op- 

 erating conditions. These showed velocities 

 ranging from approximately 1 to 8 feet per 

 second in various parts of the pool, with the 

 majority of the flows ranging between 1 and 2 

 feet per second. 



A sunnmary of observations during evalua- 

 tion of various conditions follows: 



1. Comparisons of passage times of fish 

 under half- width and full- width fishway condi- 

 tions showed that individual chinook salmon 

 made significantly faster ascents under the 

 half-width fishway condition than under the 

 full-wdth condition. Steelhead trout and sock- 

 eye salmon performed about the same under 

 either condition. Tests w^ith groups of fish 

 indicated similar results. 



2. During four capacity tests in the half- 

 width fishway, as many as 1,371 fish entered 

 the test area during a 30-nrunute entry period. 

 Performance during these tests did not indi- 

 cate that fish movement through the fishway 

 was impeded. More than 90 percent of the fish 

 in all tests passed through the fishway during 

 the 60-minute observation periods. 



3. Use of a McNary-type weir crest in lieu 

 of a Dalles -type crest, specified inthe original 

 design, improved hydraulic conditions in the 

 fishway and appeared to hasten slightly the 

 passage of fish. Brief examination of the 

 effects of a plane-surface-ogee crest indicated 



10 20 30 40 50 10 20 30 40 50 

 TOTAL PASSAGE TIME IN MINUTES 



20 30 40 50 



Figure 18. — Cumulative distribution of passage times of individual chinook, steelhead, and 

 sockeye in 1-on-lO- and l-on-16-slope fishways. Number of fish completing a six-pool 

 ascent by 1-mlnute intervals expressed as a cumulative percentage of total tested (1-on-lO 

 slope— 1960, l-on-16 slope— 1956 and 1957). 



19 



