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Joint Operations Plan: Enhanced Fisheries Without Bypass Flows Nancy Koch and Jon Monson, City of Greeley Water and Sewer Department July 1997 In the early 1990's the ArapaholRoosevelt National Forest asserted that the renewal of land use authorizations for a number of existing water supply reservoirs located in the Poudre River drainage in Colorado would include a requirement that water historically stored in these facilities be "bypassed" in order to achieve Forest Plan goals for the protection of aquatic habitat. Several of these reservoirs are owned by the City of Greeley and the Water Supply and Storage Company, The reservoirs store water when their water rights are in priority so that the water can be released for municipal and agricultural uses downstream, This storage water is typically used either in times of drought or when stored water is needed because extreme winter temperatures have reduced the natural flows in the river. The proposed bypass flow requirements would have reduced the water supply provided from these facilities by as much as 50%. The F o'rest Service and the water users disagreed as to whether the Forest Service has the legal authority to impose bypass flow requirements as a condition of the renewal of these land use authorizations. However, as an alternative to a disputing this issue, the water users and the Forest Service developed a plan for the coordinated operation of four reservoirs located in the Poudre River headwaters. This "Joint Operations Plan" (JOP) was designed to optimize aquatic habitat on National Forest lands without causing a loss of the water supply provided from these facilities. The JOP was included as a term and condition of the renewed land use authorizations for the reservoirs owned by the City of Greeley and the Water Supply and Storage Company. The JOP focused on the fact that low natural streamflow conditions in winter, which have adverse effects on aquatic species, also create a need for reservoir releases. In the Poudre River basin, naturally occurring low wintertime flows are the limiting factor for the trout fishery. Under JOP, 3,000 acre feet of storage water is released for beneficial uses by the cities when it will also augment low wintertime flows which would otherwise occur in Joe Wright Creek and the 37 miles of the Cache la Poudre mainstem. The reservoir releases are then diverted from the stream below the forest boundary for municipal water supply purposes. The Poudre River JOP provides a case study for optimization of reservoir operations to attain National Forest purposes without causing a loss of water supply from these facilities. The effects of the implementation of the lOP during 1994-95 and 1995-96 winters have been reviewed and compared to what would have occurred if bypass flow requirements had been imposed on these facilities. Actual implementation of the JOP did not cause any loss of water supply from any of the reservoirs. Attachment I is a map of the Cache la Poudre basin that shows the stream reaches and reservoirs that are included in JOP. Attachment 2 shows the trout habitat provided by each reach. Attachment 3 shows the actual improvements in Cache la Poudre River flows that resulted from JOP compared with the improvements which would have occurred with bypass flows. The envirornnental benefits of JOP were always superior to those that would have resulted from bypass flows. Attachment 4 shows that in a dry year like the winter of 1994-95, the JOP not only provided greater stream flows during the critical wintertime low flow periods than would have been provided by bypass flows, but also enhanced stream flows over what would have occurred naturally.