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~l II OOJ773 A third, and perhaps the most promising insurance pool concept, was identified late in the comment process for the study. The insurance pool could be provided by the Service's Environmental Pools: first from Ruedi Reservoir, and second from Wolford Mountain Reservoir., Each year, the Service would determine whether peak flow augmentation in the spring or low flow augmentation in the fall was the best use of water from the Environmental Pools. If the Service decided on or about May 151 of the year that peak flow augmentation was the best "use of a portion or all of water from the Environmental Pools, the Service would designate up to 20,000 acre-feet of the water as the insurance pool for preemptive releases from existing reservoirs to augment peak flows in the spring. That way, operators of existing reservoirs would have virtually no risk to yield from their reservoirs if they preemptively released water from those reservoirs. By way of example, if Denver Water released 10,000 acre- feet from Williams Fork Reservoir for peak flow augmentation and the runoff was not sufficient to refill Williams Fork Reservoir, a 10,000 acre-foot exchange or substitution would occur from Ruedi or Wolford Mountain Reservoirs to make up for the lost water to Williams Fork Reservoir. However, if Williams Fork Reservoir did fill after apreemptive release, the Service could use that 10,000 acre-foot insurance pool for low flow augmentation later in the fall. EXECUTIVE COMMITTEE RECOMMENDATION The Executive Committee of the Coordinated Facilities Operation Study (CFOPS) recommends the following two alternatives for spring peak-flow augmentation to benefit endangered fishes in the 15- mile reachofthe-GoloradoRiver;--H----H Recommendation 1: Maximize Coordinated Reservoir Operations (CROPS) - As documented in the 1997 CFOPS report, the CROPS process was developed by a group of cooperating agencies over a number of years. Its purpose is to bypass storable inflows at participating reservoirs, in a way that does not impact a reservoirs' yield, to increase the magnitude of the peak flow through the 15-mile reach in years when the predicted peak flow at the Cameo gauge is greater than 12,900 cfs, but not likely to exceed 26,600 cfs or otherwise cause flooding concerns. CROPS were first implemented in 1997, and the process has demonstrated success in 1997, 1998, and 1999. This process should be continued as the primary means of augmentirig the spring peak in the 1S-mile reach, and efforts should be made to encourage increased participation in the process. Recommendation 2: Augment the spring peak by' using up to 20,000 acre-feet of stored water in addition to CROPS - The Service and Upper Colorado River Basin Recovery Program (Recovery Program) may determine that in certain years additional peak-flow augmentation would be desirable above and beyond what can be accomplished through CROPS. Under this scenario, up to 20,000 acre-feet of stored water would be released from existing reservoirs for that purpose in addition to CROPS. The amount of water released from storage in those years would depend on the size of an insurance pool of water that would be designated by the Service on or about May 5, from existing Environmental Pools in Ruedi, Green Mountain, Wolford Mountain, and Williams Fork reservoirs (which are now used solely for summer/fall base-flow augmentation)o In any given year, the insurance pool would ensure that releases of stored water from the specified reservoir(s) for peak-flow augmentation would not jeopardize that (or those) reservoir's water supply yield. If the specified reservoir(s) re-fills and the insurance pool water is not used to offset reservoir shortages, then all Environmental Pool water would be available for base-flow augmentation. The Environmental Pool will only be reduced to the extent of a shortage in the filling of the specified reservoir(s) caused by the P:\Dala \ GEN\ CWCB\ 19665\Report Phase 2\FinalReport9.03\FinaL CFOPS_Report(9-03).doc 8