SUMMARY AND CONCLUSIONS 



Migrating adult salmonids were presented 

 with an alternative of entering one of two 

 orifices. Each orifice measured 2 by 5 feet 

 and was aligned either horizontally or verti- 

 cally at shallow or deep settings^ (3 or 9 feet 

 measured from the centerline of the orifice 

 to the water surface of the introductory area). 

 A 1-foot head was maintained on the orifices. 

 Orifice settings were changed daily and offered 

 the test fish entry to: (1) vertical and hori- 

 zontal orifices set deep, (2) vertical and hori- 

 zontal orifices set shallow, (3) shallow and 

 deep horizontal orifices, and (4) shallow and 

 deep vertical orifices. 



Unequal use was demonstrated when both 

 vertical and horizontal orifices were centered 

 9 feet from the surface, and when horizontal 

 orifices were centered at 3 and 9 feet. When 

 both orifices were at 9 feet, more salmonids 

 used the vertical orifice which, although 

 centered at the same depth as the horizontal 

 one, extended farther above and below the 

 mean depth than the horizontal orifice. When 

 horizontal orifices were centered at 3 and 9 

 feet, more salmonids used the shallow orifice 

 than the deep one. 



Unequal use was not demonstrated when both 

 vertical and horizontal orifices were centered 

 3 feet below the surface. When vertical orifices 

 were placed at both depths, percentages of 

 fish entering the shallow orifice were not 



uniformly greater than those entering the deep 

 orifice. 



In conclusion, the vertical orifice generally 

 is more suitable than the horizontal orifice 

 and the shallow orifice is more suitable than 

 the deep orifice for chinook salmon, steel- 

 head trout, and coho salmon where centerline 

 submergence is 3 and 9 feet. 



LITERATURE CITED 



COLLINS, GERALD B., and CARLH. ELLING. 



1960. Fishway research at the Fisheries- 

 Engineering Research Laboratory. U.S. 

 Fish Wildl. Serv., Circ. 98, 17 p. 

 SNEDECOR, GEORGE W. 



1957. Statistical methods. 5th ed. The Iowa 

 State College Press, Ames, Iowa, 534p. 

 U.S. ARMY CORPS OF ENGINEERS. 



1948. Annual report, passage of fish over 

 Bonneville Dam, Columbia River, Ore- 

 gon and Washington. U.S. Army Corps 

 Eng., Off. Dist. Eng., Portland, Oreg., 

 21 p. 



1960a. Annual fish passage report, North 

 Pacific Division, Bonneville, The Dallas, 

 and McNary Dams, Columbia River, 

 Oregon and Washington. U.S. Army 

 Corps Eng., Portland, Oreg., 53 p. 



1960b. Progress report on Fisheries Engi- 

 neering Research Program. U.S. Army 

 Eng., N. Pac. Div., Portland, Oreg., 

 152 p. 



MS. 1535 



