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storage to achieve the base flow ranges recommended in the 2000 Flow and Temperature Recommendations. Percentages higher than 87% could not achieve the recommended base flows of the 2000 Flow and Temperature Recommendations. Preliminary analysis of the historic inflows into Flaming Gorge did show that it might be possible to operate Flaming Gorge using a "Modified Run of River" approach to achieve the 2000 Flow Recommendations during the spring. However, it was learned through this study that the effect of water consumption above Flaming Gorge played a much more significant role than was originally thought. The Flaming Gorge model did account for the inevitability that water consumption will increase in the future. The Consumptive Uses and Losses Report, published by Reclamation, estimates that current water consumption above Flaming Gorge Reservoir is about 450,000 acre-feet per year. This is about 25% of the mean annual unregulated inflow into Flaming Gorge Reservoir. In addition to the level of water consumed, irrigation diversions, which are not entirely consumed, occur most often during the months of May through August. Such diversions are not usually completely consumed, there is a lag period before the water returns to the river. Sometimes this lag period can be as long as several months. Water consumption and diversions can significantly decrease the unregulated inflow peaks that occur during the spring. As a result, the "Modified Run of River" approach released less water than would have been released under natural conditions. For this reason, the "Modified Run of the River" could not achieve the spring flow objectives of the 2000 Flow and Temperature Recommendations. Water consumption on the Green River has an ever increasing effect on the inflows (and unregulated inflows) to Flaming Gorge Reservoir. Consequently, water consumption will further complicate Reclamation's ability to achieve the 2000 Flow and Temperature Recommendations in the future. This modeling study indicated that, in the case of a "Modified Run of River" approach for operating Flaming Gorge Dam, the current level of water consumption in the Green River Basin already makes it too difficult to achieve the 2000 Flow and Temperature Recommendations without having significant negative impacts on the other resources associated with Flaming Gorge Reservoir. Based on these findings, the "Modified Run of River" approach was not considered a viable alternative that could be included for analysis in the Flaming Gorge Environmental Impact Statement. 5.11.1.2.2 Decommissioning and Removing Flaming Gorge Dam - During the scoping process, a request was made to consider decommissioning the dam as an alternative to allow endangered fish to recover. This alternative was not selected for detailed study in the DEIS because it does not meet the purpose of and need for the Proposed Action. Specifically, decommissioning the dam would prevent continuing the authorized purposes of the dam under the Colorado River Storage Project and the Flaming Gorge National Recreation Area authorizing legislation, among others. S.11.1.3 Summary of Alternatives Analyzed in the Flaming Gorge Environmental Impact Statement 5.11.1.3.1 No Action Alternative - Under the No Action Alternative, Flaming Gorge Dam would be operated to achieve the flow and temperature regimes recommended in the 1992 Biological Opinion. These flows were intended to mimic a more natural hydrograph than occurred under previous dam operations and to protect nursery habitats of endangered fishes downstream from the Yampa River confluence. Executive Summary fi S-15