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<br />i: u.l ~ <br /> <br />THE RECOMMENDED WILDERNESS INSTREAM FLOW CLAIM BASED ON <br />RESOURCE REQUIREMENTS <br /> <br />The resource relationships described in the previous section were used to detennine the <br />quantities of water needed in the Piedra River and its tributaries to adequately protect the water <br />related resources presently existing within the proposed wilderness. They were used to <br />identify the need for flows associated with both the subsistence and long tenn maintenance of <br />biological functions within the aquatic and terrestrial ecosystems and the occurrence of <br />required hydrologic processes. <br /> <br />The principal factors considered were the known, physical and biological requirements of <br />riparian vegetation, fish, and aquatic insectS. These requirements are related and <br />interdependent and a range of streamtlows will be necessary to meet them. The requirements <br />of river otter and other riparian dependent species discussed in the previous section would be <br />met with the flows which meet the needs of the principal factors listed above. Aesthetics is <br />also an important wilderness value. It is assumed that maintenance of this value would also be <br />achieved with the instream flows that have been quantified on the basis of the factors listed <br />above. <br /> <br />Analysis of these factors resulted in the identification of four required levels or ranges of flow; <br />see Table 2. Two of the flow levels are related to winter, early spring, and fall low flows and <br />are based primarily upon biological function and survival needs: <br />. Qu ' subsistence flow; <br />. Qu . biological maintenance flow; <br />The remaining two tlow levels are related to the higher ranges of flow typically occurring <br />during the spring, summer. and fall and are based primarily upon the biological needs of both <br />terrestrial and aquatic species and on the maintenance of physical habitat features: <br />. the range of tlows between QA' average annual tlow and Qu. tlow wiili a return period of <br />1.5 years; and <br />. the range of flows exceeding Qu. <br />The Qu tlow occurs an average of two out of every three years. It dosely approximates the <br />level of flow needed to just fill the active channel. <br /> <br />Page 15 <br />