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<br />When the 20,000 acre-foot commitment from Ruedi Reservoir was released to <br />benefit endangered fish, Reclamation then looked at the remaining pools in <br />Green Mountain Reservoir, On October 7, Reclamation found that approximately <br />30,000 acre-feet of water remained in the Green Mountain Reservoir historic <br />users pool. Reclamation then made a determination that a discretionary power <br />release could be made from Green Mountain Reservoir which would help maintain <br />flows in the IS-Mile Reach. This determination was possible because the <br />irrigation season was near completion and all minimum pool requirements could <br />be maintained. <br /> <br />Flows in the IS-Mile Reach <br /> <br />In 1990, the Recovery Program, in cooperation with the Colorado Division of <br />Wildlife, had a USGS gage installed in the IS-Mile Reach just below the Grand <br />Valley canal headgate and the Orchard Mesa power plant return. This gage was <br />used to monitor flows in the IS-Mile Reach and to provide data for water <br />availability and instream flow studies. The benefits of the Ruedi releases <br />can be simulated in the IS-Mile Reach by reducing the Ruedi releases by 10 <br />percent and adding that number to the Palisade gage with a two-day offset to <br />account for travel time. Figure 1 displays flows at the Palisade gage with <br />and without Ruedi augmentation. During the release period, there were 49 days <br />when flows at the Palisade gage were below the 600 cfs threshold target <br />established for 1994. With the supplemental releases, the 600 cfs minimum was <br />met 56 percent of the time. Based on 1994 data, the 20,000 acre-feet pool in <br />Ruedi would have been about enough to maintain 600 cfs target in the IS-Mile <br />Reach, based on perfect hindsight. This did not happen in 1994 because Ruedi <br />water was used too conservatively in August and channel capacity constraints <br />limited the volume of water that could be delivered when flows were far below <br />600 cfs in the 15 Mile-Reach, <br /> <br />The Recovery Program also contracts with Richard D. Piland and Associates for <br />the operation of a temporary gage at the lower end of the IS-Mile Reach, <br />Figure 2 displays the flow gains between the upper and lower ends of the 15- <br />Mile Reach. Based upon the 1992 data from the gage at the lower end of the <br />IS-Mile Reach, flows increased by an average of approximately 200 cfs. A <br />detailed analysis of Ruedi Releases for endangered fish and accretions in the <br />15 Mile-Reach is being prepared by Leonard Rice Consulting Water Engineers. <br />The Leonard Rice report is in preparation and will contain all the 1994 data <br />and analysis. <br /> <br />4 <br />