Based on the individual response (under- 

 water observations) of 492 juvenile steelhead 

 trout and 151 young coho fry, with an approach 

 to bypass water velocity of 1 to 1.4 (140 per- 

 cent), only 7 percent of the steelhead (34 fish) 

 and 2 percent of the coho (3 fish) showed any 

 hesitation in accepting the bypass. The steel- 

 head generally passed into the bypass indi- 

 vidually or in small groups of up to five. The 

 cohos moved through generally singly or in 

 groups of two to three, possibly having broken 

 away from a larger school at the intake of the 

 diversion canal. 



EFFECTIVENESS OF TRAVELING SCREEN 



The most important feature in the develop- 

 ment of the traveling screen has been the near 

 elimination of a wide range of problems pre- 

 viously encountered with all other systems in 

 the diversion and collection of juvenile fish. 

 For example, juvenile migrants carried onto 

 louvers are swept through and lost; those 

 carried onto industrial water screens or drum 

 screens could be injured or killed because of 

 turbulent flow. These types of screens in no 

 way assist the migrants in their efforts to 

 reach the bypass. In contrast, fish swept onto 

 a traveling screen are effectively carried into 

 the bypass. 



Another unusual and important advantage of 

 a traveling screen is its potential capacity to 

 collect eggs and weak, free-swimming larvae 

 and fry and to move them directly into the 

 safety of the bypass. As the screen can be 

 moved to match the velocity of the water, 

 impingennent of sn-iall fish and eggs is gradual 

 and not damaging. Furtliermore, the operating 

 effectiveness of the traveling screen is not 

 altered by extreme fluctuation of water level. 



SUMMARY 



An improved traveling screen for diverting 

 juvenile migrants from rivers, streams, and 

 canals was developed in 1965-67. This struc- 

 ture, model V, was tested during the spring of 

 1968 within the 8.53-m. wide Stanfield Irriga- 

 tion Canal, a diversion of the Umatilla River 

 near Echo, Oreg. The screen, which hangs 

 vertically, traverses the canal at an angle 

 of 20° to waterflow and returns above water to 

 minimize drag. The weight of the screen and 

 the water pressure against it are supportedby 

 a wire-rope suspension structure. 



The main suspension structure consists of a 

 single main wire rope between two end towers. 

 Suspenders from the main wire rope carry a 

 20.3-cm. diameter pipe (the torque tube), which 

 acts as a longitudinal stiffening member and 

 as a base for mounting equipment. 



Side-wire ropes projecting at right angles 

 to the pipe are attached to anchors along the 



canal bank. These side-wire ropes take the 

 lateral loads, imposed on the pipe beam by 

 water pressures and by wind on the return 

 journey. 



Water and wind acting on the screen create 

 a torque on the pipe beam element. This 

 torque is resisted by the couples formed by the 

 side-wire ropes and the torque wire ropes. 

 The torque wire ropes are attached to the 

 return screen support arm and fastened to 

 anchors. 



The screen is supported from traveling 

 carriers, fitted with a cantilever swing tube 

 that allows the screen to form a rectangle or 

 parallelogram, depending upon which section 

 of the track is being traversed. Cantilevers 

 are tied together- -top and bottom--by tubing 

 to form a frame. The screen panels are fornned 

 with a rubber bulb for attachment to the 

 frame. 



The carriers are driven by a gear motor 

 driving the take-up sheave through a spocket 

 and roller chain. This sheave in turn drives 

 a wire-rope, attached to the carriers through 

 a special slip. 



Operation of the traveling screen requires 

 such considerations as rate of travel, head 

 loss, fish deflection, and bypass flow. The 

 Stanfield screen was usually moved at a 

 velocity of 40 cm.p.s.--a relatively slow rate 

 due to small debris load and absence of im- 

 pingement of fish. 



Use of a 12.7-mm, stretched nylon mesh, 

 with an extensive effective open area of 72 

 percent, caused a head loss of only 9,14 mm. 

 at the low water velocity of 73 cm,p,s. The 

 mesh was small enough to retain all fish. 



The curtain of continuously nnoving netting 

 deflected 97 to 100 percent of the young steel- 

 head and coho salmon; the self-cleaning action 

 of the screen was sufficient to keep the netting 

 clean at all times regardless of amount or type 

 of debris. During the operation of the traveling 

 screen, velocity of water in the bypass was 

 maintained at 140 percent of the mean velocity 

 in the canal to insure acceptance by the young 

 nnigrants. 



Based on tests and 3 years' experience in 

 operating the traveling screen, the following 

 conclusions appear warranted: (1) use of the 

 traveling screen in the deflection of young 

 salmon and trout is practicable and desirable, 

 (2) operational efficiency remains high even 

 though water levels fluctuate, (3) it is possible 

 to deflect fish when water velocities are high- - 

 if fish become impinged they are carried to 

 and released directly within the bypass, 

 (4) operational wear is reduced because all 

 traveling units are above water, (5) correctly 

 designed, the screen is self-cleaning, (6) head 

 loss is small as only single-screening is in- 

 volved in contrast to double-screening for 

 many other systems, (7) individual net panels 

 can be easily removed and replaced, and 

 (8) the reduced need for supplementary 



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