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<br />DClfJ810 <br /> <br />DRAFT <br /> <br />FINAL DRAFT. 12/19/91 <br /> <br />THE RECOMMENDED INSTREAM FLOW CLAIM BASED ON RESOURCE <br />REQUIREMENTS <br /> <br />The Piedra River channel and the ecosystems associated with it have been shaped by and bave <br />adjusted to the current range in magnitude, frequency. and duration of streamflow. The <br />viability and health of the aquatic ecosystem can not be separated from the viability and health <br />of the terrestrial ecosystem. Each conrributes to the composition, structure, and function of the <br />other and modification of the relationships between either ecosystem would affect change in the <br />other. Any claim for less water than the current run of the river carries with it the probability <br />that the interactions between these ecosystems would be altered and that conditions within the <br />Piedra wilderness would change. However. the proposed claim is based on resource needs and <br />represents the minimum amoUDt of water required to adequately protect the water related <br />resources and values at approximately their present potential. <br /> <br />The resource factors described in the previous section were used to determine the quantities of <br />water needed in the Piedra River and its tributaries. They were used to identify the need for <br />flows associated with subsistence and long term maintenance of biological functions within the <br />aquatic and terrestrial ecosystems and with the occurrence of required hydrologic pn>ces!:et. <br />Use of these factors resulted in the identification of four required level! or ranges of flow: two <br />related to winter and early spring low flows and based primarily upon biological function and <br />survival needs (Qu . subsistence flow and Q12 . biological maintenance flow); and two related <br />to higher ranges of flow occurring during spring. summer. and faIl based upon biological <br />needs of both terrestrial and aquatic species and on maintenance of habitat features (the range <br />of flows between Q.... average annual flow and Qu. flow with a return period of 1.5 years and <br />t,be range of flows exceeding Q..J. See Table 2. <br /> <br />FLOW LEVEL PRIMARY PURPOSE <br />Qu fisheries subsistence <br />macroinvertebrate babitat <br />Qu fish spawning <br />macroinvenebrate habitat <br /> tisheries maintenance <br /> spawning <br /> macroinvenebrate habitat <br /> riparian seed dispersal. seedling establishment. plant growth <br /> sediment movement <br />Q... through Qu maintenance of pools. riffles. and glides <br /> prevent embedding of substtate <br /> maintain ttibuury access <br /> transoon woodv debris <br /> maintenance of riparian zone composition. structure. and <br />Greater than Qu function <br /> cottonwood regeneration <br /> maintenance of rioarian zone oosition and size <br /> <br />Table 2 <br /> <br />Page 13 <br />