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DEPARTMENT OF FISH AND GAME 



This is a perforated plate fish screen with gear drive. The perforated plate has been inserted 

 into the downstream end of a form originally built for a revolving drum screen. Young trout 

 and salmon descend the irrigation ditch as far as the screen, then are diverted back to the 

 parent stream through the bypass channel directly in front of Fish Hatchery Foreman E. W. 

 Murphey, the inventor of the perforated plate screen. Siskiyou County, 1951. 



STREAM AND LAKE IMPROVEMENT 

 Fish Screens 



For many years California laws required owners of water diversions 

 to install and maintain fish screens as required by the State. The results 

 were not satisfactory. It was difficult and expensive for each owner to 

 have his screen made to order, and many times the device was of poor 

 quality. In 1952 the State Legislature amended the fish screen laws to 

 provide that the Department of Fish and Game will install, maintain, 

 repair, and replace screens in nonpower ditches under 250 second-feet 

 in capacity. 



Fish screen construction, installation, and maintenance by the Bureau 

 of Fish Conservation was again centered at its stream improvement 

 headquarters at Yreka, Siskiyou County, and at its smaller shop at 

 Weaverville, Trinity County. Two successful modifications of the per- 

 forated plate screen were developed at these shops during the biennium. 

 The "submerged plate" type is particularly successful in stopping very 

 small steelhead fingerlings, while the "diagonal plate" type permits a 

 large capacity screen to be constructed in a narrow ditch. 



Five new perforated plate screens were installed in Trinity County 

 and eight in Siskiyou County. 



