open shafts called gatewells. The fish are then passed through 

 openings in the wall into the ice sluice, which carries them 

 to a safe location in the tailrace. 



The Corps has equipped all 44 gatewells at McNary Dam 

 with submerged portholes leading to the ice sluice and is 

 providing funds for their evaluation. We expect to complete 

 this phase of the research in 1969. Meanwhile, we are de- 

 veloping a traveling screen to divert the fish from intakes 

 into gatewells. Placement of this guiding device within 

 turbine intakes, rather than in the forebay, has two major 

 advantages: (1) Trash racks across the mouth of the in- 

 takes, desigiied to protect turbines from large logs, also 

 protect the guiding device and (2) the fish, as they are drawn 

 deeper into the intake, tend to concentrate in the upper 

 water mass along the ceiling, making it possible to divert 

 greater percentages of the fish by screening smaller quantities 

 of water. The prototype traveling screen will theoretically 

 guide 70 to 80 percent of the fish into the gatewell-sluice 

 bypass. Should traveling screens be placed in all turbine 

 intakes of all 15 low-head dams planned for construction, 

 the total cost would be about the same as the cost of fish 

 facilities for adult salmon at only two of these dams. 



Deflection of Migrating Fingerlings 



Fishery biologists and hydraulic engineers have spent 

 years trying to divert and collect migrating juvenile fish at 

 hydroelectric and irrigation structures. To deflect fish, they 

 have experimented with bands of rising bubbles, curtains of 

 hanging chains, electrical stimuli, jet streams, light, louvers, 

 and sound. Under certain conditions these systems worked 

 but were never completely reliable. Vertically traveling 

 screens caused losses or considerable damage to fish. A 

 new development by our laboratory — the horizontally trav- 

 eling screen — provides many practical solutions. 



As the fish move downstream with the river current, 

 they encounter the screen which is set diagonally to the 



current (fig. 39). The screen, made of interlocking panels, 

 moves toward a bypass channel or collection point on the 

 shore. Because the velocity of the screen matches that of 

 the river flow, fish are diverted or impinged gently and led 



FIGURE 39.-An artist's concept of the traveling screen, Model 

 VII, as it might appear within a river or canal. 



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