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Upper Spavinaw, impounded in January, 1952, is one of two water-supply- 

 reservoirs constructed and operated by the City of Tulsa on Spavinaw Creek, 

 Delaware County, Oklahoma. The 3,192-acre lake formed has an average depth 

 of 25 feet and a maxirauii depth of 90 feet. It resembles a long, narrow, 

 slightly crooked finger, with margins roughly serrated by numerous coves. 

 Relatively flat shorelines, shallow waters, and silted, mud bottoms are re- 

 stricted almost entirely to a small headwater region. Siltation has been 

 slight, and the reservoir has remained clear since impoundment. 



It is recognized that broad ecological differences are associated with 

 the differences in turbidities and that turbidity is only one of several 

 factors of possible influence on the biology of the two reservoirs. It is 

 believed, however, that differences in turbidities were closely related to 

 differences in growth, relative abundance, and reproductive success of certain 

 species studied, as well as for differences in plankton production, rates of 

 fisherman use, and fishing success, in the two reservoirs. 



FINDINGS FROM THE RESERVOIR STUDIES 



Results from the clear and muddy reservoirs were consistent with those 

 from the clear and muddy ponds. The clear reservoir exhibited faster growth 

 by all species in a population dominated by gizzard shad, largemouth bass and 

 bluegill, as contrasted with a slower-growing population in the muddy reservoir 

 having catfish, carp, carpsuckers and stunted white crappies as the principal 

 fishes. Young-of-year bass, crappies and other scaled fishes were generally 

 scarce in the muddy reservoir and there was an abundance of young catfishes. 

 The reverse was found in the clear reservoir. 



