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<br />r-.. <br /> <br />02/14/96 <br /> <br />10:07 <br /> <br />tt303 245 6933 <br /> <br />FISH" WILDLIFE <br /> <br />......... CWCB <br /> <br />III 006 <br /> <br />---"-- <br /> <br />natural hydrograph. However, to date, a dry year scenario has not yet been <br />available. Because of this, all planned research can not be completed. The <br />objective is to re-create a high spring peak flow providing a gradually <br />ascending 11mb followed by a gradually declining recession limb to low, stable <br />flows throughout the summer, fall, and winter, The Service and the biological <br />experts believe that this is the best opportunity available to bring the <br />endangered fish back from the brink of extirpation in the San Juan River. By <br />returning the river to a more natural hydrograph and raising the spring peak <br />flows, the Service believes there will be an increase in reproduction and <br />recruitment of the endangered fish in the San Juan River. This operation of <br />Navajo Dam is the most important feature of the reasonable and prudent <br />alternative both for the research period and the long term, <br /> <br />In order for there to be a permanent annual average depletion of 57,100 acre- <br />feet of water from the Project, there must be a guarantee that, based on the <br />results of the research program and dependent upon prevailing hydrology, <br />Navajo Dam will be operated to mimic the natural hydrograph for the life of <br />the Animas la-Plata Project. Under Section 7(a)1 Reclamation has agreed to <br />reoperate Navajo Dam for the recovery of the endangered fishes. Releases for <br />the endangered fish will be legally protected to and through endangered fish <br />habitat to lake Powell. However, until all research is completed, the <br />required water delivery schedule for the life of Navajo Dam (in terms of <br />hydrograph shape, timing, volume, and frequency) is unknown. Final year-round <br />flow recommendations will be determined at the conclusion of the research. <br /> <br />Under present conditions, computer simulations predict that by providing a <br />300 cfs minimum winter flow, 300,000 acre-feet would be available 96 percent <br />of the time, thus providing maximum fleXibility to mimic a natural hydrograph <br />(shape, timing, and frequency). However, under full depletions (adding in all <br />future proposed projects up to each State's full compact allotment), the <br />300,000 acre-feet of water from the Navajo Reservoir would be available only <br />33 percent of the time, which indicates that the ability to provide all four <br />elements of a natural hydrograph (shape, timing, volume, and frequency) would <br />be severely restricted. The research, therefore, is directed towards <br />determining how Navajo Reservoir releases can best be used in terms of <br />mimicking the natural hydrograph. This information will be utilized by the <br />Service in coordination with Reclamation to determine reservoir releases <br />needed for the endangered fishes. <br /> <br />The seventh element 1s .legal protection of releases from Navajo Dam and <br />Reservoir to and through endangered fish species habitat. It is not enough to <br />only release water from Navajo Dam. There also must be guaranteed delivery of <br />the water so that 1t provides the habitat improvement necessary to maintain <br />and increase the endangered fish population in the San Juan River. To ensure <br />legal protection of releases for listed fish, a Memorandum of Understanding <br />and Supplemental Agreement have been developed and executed (Appendix B). <br /> <br />The Recovery Implementation Program for the San Juan River is now developed <br />and Reclamation is providing funding for the research effort through the <br />Recovery Implementation Program. Funding of the research and all other <br />recovery activities for the endangered fish of the San Juan River has become a <br /> <br />5 <br />