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o 028 o .... x ~ LL. 24 o C/) c( 20 UJ a:: < UJ U 16 < LL. a:: ::::> C/) 44 40 36 32 12 8 4 o //// J...... ~tttt~tt .......................... ............. :::::::::::::::::::::::::: ~jj~~jII~jj~jjI~~ ::::::::::::::;:;:;:::;::: mrrrrmt :::::::::::::::::::::::::. ............. :::::::::::::::::::::::::" ............. .:.:.:.:.:.:.:.:.:.:.:.:. :::::;:::::;:;:::;:;:::::: ............. :::::::::::::::::::::::::: Ij:[[~IIjII :::;:::;:;:;:::::;:::;:::: j~~ ~~~~~~m~mr~~~~~~~ fft)ff~~ ............. :::::::::::::::::::::::::: :::::::::::::::::::::::::: :::::::::::::::::::::::::: ::111:11111111111111111111 :::::::::::;:;:::::;:::::: ;:::::;:::::::::;:;::::::. ~ftrfff~ mrrmmr~f .:::::::::::::::::::::::::: i!!lll!!l!!!ll!!!ll!!!!l!! fIfItI~~ ............. ///// ///// ////// ////// 171 93 51 25 STREAMFLOW (CU. FT./SECOND) in streamflow could reduce the area of fast water or riffles. However. the physical features of the stream channel and hydraulic gradient determine some of the responses in the type of water under different flows. as shown by Hill (1965) for different reaches in the White River. Colorado. A quick and easy method to determine flow requirements for the pro- tection of aquatic resources in both warm-water and cold-water streams employs average flows (Tennant. 1976; table 12). This ''Montana method." SLOW SHAL LOW which is based on n\DDerous observations and flow studies. has shown that the condition of the aquatic habitat is remarkably similar in streams of different sizes carrying the same portion of average flow. Using this method. Tennant suggests altering the flow reg~en of a stream to fit DE EP SLOW different hydrologic cycles, Such an alteration could be used to favor game species such as fall-spawning brown trout. Tennant also points out that the results of the application of this method are consistent from .' .' ., ... stream to stream. and from state to state. ~ Many recommendations concerning streamflows have been made on rather (' . small rivers but recommendations for larger rivers have been proposed only .. .. ~ recently (Banks and coauthors, 1974). From studies of the Green River in , .. ... .. RIFFLE Wyoming between Fontenelle Dam and Flaming Gorge Reservoir. with flows of , , 1.600. 800. 500. and 300 cfs. Banks and coauthors recommended 500 cfs for a winter survival flow (November through March). with an emergency short-term flow of 300 cfs for less than thirty days and a minimum pro- duction flow of 800 cfs (April through October). Also. these investigators POOL DEEP FAST recommended that a sediment-flushing. or habitat maintenance. flow of 800 to 1.600 cfs be used when necessary. Figure 8. Type of Habitat Under ~our Streamflows at One Station in the North Channel of the White River Sou~ce_:~ _~... ~R. Hill. Wh~i:.e- ~iver Survey (Denver. Colo.. Colorado ____ _~_'-__~__ ft______'- n"__.l_"__ ~_...a___' A"~ i , ~ {;' .,t 'I "~ ....'li.: