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<br />39 <br /> <br />1992 (Appendix C) in accordance with funding agreements that are <br />reached among Recovery Program participants. <br /> <br />Discussion <br /> <br />The jeopardy and adverse modification conclusion in this biological oplnlon is <br />based on full Project development which would result in an average annual <br />depletion of 149,220 acre-feet of water. To offset the likelihood of jeopardy <br />and adverse modification of critical habitat, the reasonable and prudent <br />alternative presented herein includes construction and operation of the <br />Phase I, Stage A of the Project, which would initially result in an annual <br />depletion of 57,100 acre-feet, a considerably smaller depletion. However, <br />even this smaller depletion is biologically acceptable only if all elements of <br />the reasonable and prudent alternative are fully implemented. Therefore, <br />Phase I, Stage A could not exceed 57,100 acre-feet until all elements are <br />fully implemented. This would require that Reclamation operate Navajo Dam to <br />provide the'flexibility to mimic a natural hydrograph as directed by the <br />Biology Committee and as demonstrated by the model runs that show availability <br />of 300,000 acre-feet of water 96 percent of the water years for the endangered <br />fishes. In order to achieve this, a low winter flow (about 300 cfs), if <br />hydrologic conditions permit, below Navajo Dam would be required. Therefore, <br />until low winter flows, below the existing low of 500 cfs become part of <br />Navajo Dam operations, Phase I, Stage A could not exceed an annual depletion <br />of 57,100 acre-feet. <br /> <br />The operation of the full scale Project (Figures 1-18, Appendix A) would <br />result in a significant reduction of spring peak flows through the endangered <br />fish habitat in the San Juan River, while the operation of the Project in <br />accordance with the reasonable and prudent alternative takes much less water <br />on a fairly steady basis throughout the year. When one compares the initial <br />depletion of the Project to the hydrograph of existing conditions with the <br />Navajo Dam operated to mimic a natural hydrograph (Figures 1-18, Appendix A), <br />there is negligible change to the hydrograph shape and/or timing of spring <br />peak flows with the reoperation of the Navajo Dam. This is important in order <br />to provide the gradual ascending and descending limbs of the spring peaks. <br />The water from Navajo Reservoir storage is still available 96 percent of the <br />water years to provide the same shape, timing, and frequency, assuming a low <br />winter flow of approximately 300 cfs. <br /> <br />Ongoing research is an important feature of the reasonable and prudent <br />alternative. It was sufficient new information from research conducted as a <br />result of the 1979 biological opinion that led to the reinitiation of <br />section 7 consultation for the Project in 1989. It is the implementation of <br />research which will provide the Service with further information about the <br />biological needs of the fish specific to the San Juan River Basin and how <br />these needs can best be met. The future development of water in the San Juan <br />River Basin, including the proposed remaining depletions of the Project, will <br />be highly dependent on the outcome of the biological studies which are <br />required as part of this reasonable and prudent alternative. In making future <br />decisions about endangered species, the Service must use the best scientific <br />and commercial data available. Ongoing research results will provide that <br />necessary data. <br />