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<br />Draft Fmal Completion Report to UDWR for Contract #93-1070. Amendment 3 <br /> <br />INTRODUCTION <br /> <br />"Quantification 'of the structure and function of complex systems, like the Upper Colorado River Basin <br />ecosystem, in time and space must be based on long-term (> 5 years) measurements in order to detect patterns <br />or trends that in shorter time frames are overwhelmed by variability. Hence, an ecosystem approach strives to <br />determine how and why the river changes in time and space. not simply to describe current conditions." <br />Stanford. 1994 <br /> <br />Virtually every major river in the western United States is controlled by one or more large dams. Substantial <br /> <br />research has shown that the river downstream from a dam adjusts physically. and its waters may change chemically and <br /> <br />biologically. after dam completion (for example Williams and Wolman, 1984; Tyus, 1992). These changes affect the <br /> <br />downstream river corridor ecosystem. The dams of the Colorado River basin, such as Flaming Gorge Dam on the Green <br /> <br />River. Utah. have altered the river corridor ecosystem. and these ecosystem changes are believed to be a factor in the <br /> <br />decline of endangered fish populations to critical levels (Stanford, 1994). One of the many dam-related factors that may <br /> <br />be responsible for the demise of these populations is the availability of nursery habitat for larval fish (Tyus and Karp. <br /> <br />1991). Consequently. species recovery. as mandated by the Endangered Species Act (ESA). will in part depend on <br /> <br />enhancement of available nursery habitat. <br /> <br />The purpose of this research is to evaluate the geomorphic basis and annual changes in nursery habitat for the <br /> <br />endangered Colorado squawfish (Ptychocheilus Lucius) near Ouray. Utah. Unlike previous efforts to quantify nursery <br /> <br />habitat in the Green River (for example. Pucherelli and others. 1990), this research attempts to integrate <br /> <br />interdisciplinary data from multiple spatial scales collected over a multi-year period. These data are used to address how <br /> <br />nursery habitat characteristics and availability are affected by specific water releases from Flaming Gorge Dam. Results <br /> <br />from this research may improve recommendations for discharges that form. mllintllin, and maximize Colorado squawfish <br /> <br />nursery habitat. <br />