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The present study was initiated to assess the geomorphic effects of coordinated reservoir <br />operations, and to develop a better understanding of the timing of sediment supply and sediment <br />transport in key reaches of the upper Colorado River. The specific objectives of this study were <br />to: <br />1. Monitor rates of channel change and assess the geomorphic effects of coordinated <br />reservoir releases and normal snowmelt flows. <br />2. Define the window of time of peak sediment delivery from unregulated tributaries. <br />3. Verifying discharge thresholds for coarse-sediment transport. <br />4. Examine processes of fine sediment transport and deposition on the falling limb of <br />the hydrograph. <br />5. Provide data on thresholds and durations of discharges that perform important <br />geomorphic functions so that biologists can integrate this information with biological <br />information and refine flow recommendations as necessary. <br />Field measurements coinciding with the late spring-early summer period of peak runoff <br />were taken at various locations in the 15- and 18-mile reaches from 1998 through 2004. An <br />array of techniques was used to monitor changes in channel geomorphology and the movement <br />of fine and coarse sediment in response to different flow levels. Results of this work will aid in <br />refining flow recommendations so that, in the future, reservoir operations can be adjusted and <br />releases can be timed to provide the greatest benefit to the endangered fishes.