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<br />33 <br /> <br />.1 <br /> <br />3. Reclamation will operate the Navajo Dam under study guidelines developed <br />under element 2 for the research period so that releases mimic a natural <br />hydrograph. Test flows will be provided to re-create a wide range of flow <br />conditions including high flows similar to 1987, which are hypothesized to <br />benefit reproduction and recruitment in the endangered fish community. <br />Release schedules will be determined by the Service and Reclamation based <br />on research studies and with the available water supply after meeting <br />baseline depletions. These release schedules shall meet the limitations <br />on the outlet works facilities and safe routing of hydrological events in <br />the Upper Colorado River Basin. The Bureau of Reclamation also has <br />requested initiation of Section 7 consultation on the operation of Navajo <br />Dam, including a commitment to operate the dam for the conservation of the <br />endangered fish. <br /> <br />4. At the end of the approximately 7-year research period, the Navajo Dam <br />would be operated to mimic a natural hydrograph for the life of the <br />Project based on the research. <br /> <br />5. There shall be a binding agreement(s) that the reservoir releases (for <br />both the study period and for the life of the Project) are legally <br />protected to and through the endangered fish habitat to Lake Powell. This <br />agreement will include a commitment for the appropriate parties to develop <br />and implement a Recovery Implementation Program for the San Juan River <br />within 1 year. <br /> <br />Discussion <br /> <br />The following discussion describes why the Service believes that the five <br />elements of the reasonable and prudent alternative, if fully implemented, would <br />avoid the likelihood of jeopardy to Colorado squawfish associated with initial <br />depletions from development of the Project. The Service agrees with the <br />consensus of the Biology Committee that altered flows are the most important <br />impact on the continued existence of endangered fishes based on the best <br />information currently available. <br /> <br />The jeopardy conclusion in this biological opinion is based on full Project <br />development which would result in a net annual depletion of 154,800 acre-feet <br />of water. To offset the likelihood of jeopardy, the reasonable and prudent <br />alternative presented herein includes construction and operation of the Project, <br />which would result in a net annual depletion of 57,100 acre-feet, a considerably <br />smaller depletion. However, even this smaller depletion is biologically <br />acceptable only if all elements of the reasonable and prudent alternative are <br />fully implemented. The operation of the full scale Project (Figure 3, <br />Appendix B) would result in a significant reduction of spring peak flows through <br />the endangered fish habitat in the San Juan River, while the operation of the <br />Project in accordance with the reasonable and prudent alternative takes much <br />less water on a fairly steady basis throughout the year. When one compares the <br />initial depletion of the Project to the hydrograph of existing conditions with <br />the Navajo Dam operated to mimic a natural hydrograph (Figures 1-6, Appendix E), <br />there is negligible change to the hydrograph shape and/or timing of spring peak <br />flows with the operation of the Navajo Dam. This is important in order to <br />provide the gradual ascending and descending limbs of the spring peaks. The <br />water from the Navajo Reservoir storage is still available 96 percent of the <br /> <br />. . I <br /> <br />~! <br /> <br />81 <br /> <br />-,j <br /> <br />.~ <br /> <br />~ - <br />',., <br /> <br /> <br />',~ <br />