Traveling Screen for Removal of Debris From Rivers 



By 



DANIEL W. BATES, Fishery Biologist 

 ERNEST W. MURPHEY 1 , Laboratory Mechanic 



and 

 MARTIN G. BEAM 2 , Fishery Biologist 



National Marine Fisheries Service Biological Laboratory 



2725 Montlake Boulevard East 



Seattle, Washington 98102 



ABSTRACT 



This report describes the features and operation of a traveling debris screen, 

 installed within a 12.2-m wide test flume in the Grande Ronde River near Troy, 

 Oreg. The National Marine Fisheries Service developed the screen to improve re- 

 moval of debris from canals and rivers of the Pacific Northwest and to reduce 

 costs of removal. Trash racks are now used to remove debris, but they have been 

 considered impractical because of maintenance difficulties during floods and be- 

 cause of their large size. 



INTRODUCTION 



Diversion structures installed in rivers to 

 deflect fish migrating through hazardous areas 

 need to be protected from damage by large 

 debris. This need is now met with trash racks 

 of conventional design. These racks are con- 

 sidered impractical, however, because of main- 

 tenance difficulty during floods and because of 

 the size of the structure required. 



The traveling debris screen 3 described in this 

 report was developed by the National Marine 

 Fisheries Service to overcome these disadvan- 

 tages. It introduces such features as a wire- 

 rope suspension structure and an endless trav- 



1 Present address: 1450 Murphy Creek Road, 

 Grants Pass, Oreg. 97526. 



- Present address: Marine Dept, P.O. Box 10142, 

 The Terrace, Wellington, New Zealand. 



1 The traveling debris screen was developed concur- 

 rently with studies of experimental traveling screens 

 for deflecting juvenile migrants into a bypass for safe 

 passage (Bates, Murphey, and Prentice, 1970; Bates 

 and VanDerwalker, 1970) and incorporates certain 

 features of the traveling screens. 



eling screen that will contribute to the success- 

 ful deflection and removal of debris. 



The screen may be generally described as a 

 conveyor belt, placed on edge in a diagonal line 

 (20° angle to direction of stream) across the 

 path of debris. The impinged material is car- 

 ried easily and rapidly into a quiet pond for 

 removal by conveyor. 



The traveling debris screen was installed in 

 a concrete test flume in the Grande Ronde River 

 near Troy, Oreg., during the spring of 1967. 

 At this site an island divides the river into two 

 channels; the test flume occupied the full width 

 of the left-bank channel. The test flume was 

 103.7 m long, 12.2 m wide, and 3.7 m deep. 

 It was capable of holding all or any portion 

 of the channel flow. Three electrically operated 

 steel gates at the head of the structure con- 

 trolled flow. Rate of flow was regulated by 

 stop logs at the downstream end of the channel. 



This report describes the design and oper- 

 ation of the screen and the results of three 

 series of mechanical tests on its effectiveness 

 and stability. 



