PROGRESS IN BIOLOGICAL INQUIRIES, 1931 483 



system through the Sun River Slope Canal. The site selected for 

 the installation of the screen is at a point approximately I/2 mile 

 below the outlet of Pishkun lieservoir. At this point the canal 

 widens out into a natural pond, affording favorably reduced veloci- 

 ties just upstream of where it is proposed to stop the hsh by means 

 of the screen. 



The typical section of the Sun River Slope Canal has a bottom 

 width of 30 feet, and for the capacity flow of 1,435 second-feet the 

 depth of water is 11.5 feet. In order to maintain satisfactorily low 

 velocities through the screen box the design calls for installation of 

 the screen in five sections, each having a width of 14 feet and a 

 diameter of 13 feet. The supporting box of reinforced concrete 

 contains approximately 370 cubic yards of 1:2:4 concrete and ap- 

 proximately 50,000 pounds of reinforced steel. The five sections of 

 screen are driven by three paddle wheels located just downstream 

 from the screen cylinders and connected to the latter by means of 

 chain and sprocket gearing. In the fabrication of the screens and 

 paddle wheels approximately 20 tons of steel are required. The 

 covering of the screen cylinder is to be No. 10 gage galvanized steel 

 or copper wire screening having a %-inch clear opening mesh. 



Final working drawings of this screen will be filed with the Recla- 

 mation Service so that reference to them may be had by the Reclama- 

 tion Service on all new projects wherein a fish-conservation problem 

 is involved. This in itself is held to be justification for the time and 

 expense contributed by the Bureau of Fisheries in preparing these 

 plans. It will make possible, at the time that new projects are first 

 planned, for proper fish screens to be provided in the original designs 

 of the diversion structure, which will work both for the conservation 

 of fish and economy in construction. 



Cooperating with the Oregon Game Commission, field examina- 

 tions were made and designs and cost estimates prepared covering 

 mechanical-screen installations for Farmers Irrigation Ditch (ca- 

 pacity 100 second-feet), on Hood River, and C. O. I. Canal (capacity 

 650 second-feet), Pilot Butte Canal (capacity 450 second-feet), 

 Tumalo Canal (capacity 150 second-feet), Swalley Canal (capacity 

 125 second-feet), and Arnold Canal (capacity 100 second-feet), the 

 last five named being on the Deschutes River. 



In the spring of 1931 the Utah Power & Light Co. applied to the 

 Bureau of Fisheries for aid in solving the fish-screening problem at 

 their Lift Plant, situated on Bear Lake. This lake constitutes one of 

 the largest water-storage projects in the country. The problem in- 

 volves trout of various kinds which frequent the waters of Bear 

 River and Bear Lake. The situation is a peculiar one. Under the 

 scheme of operation water is lifted from the lake by means of large- 

 capacity, low-lift pumps and discharged through a canal into Bear 

 River, where it flows through a series of power plants. During high 

 stages of the river the flow is reversed, and the canal conveys water 

 from the river through the pumping plant for storage in the lake. 



The situation was studied very carefully in the field in company 

 with the district supervisor of the Bureau of Fisheries, the State 

 Game Commissioner of Utah, and the engineers of the Utah Power & 

 Light Co. It was decided that instead of using either electric or 

 mechanical screens, which for an installation of this magnitude 



