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Reservoir Operating Studies conditions because the only demands assumed to have increased contractual access to storage are municipal demands (which had only isolated shortages in the "without project" scenario). Most increased storage was assumed to be either reserved for the power plants or used for instream flow enhancement. If contractual access to these power pools were granted for all modeled industrial demands, shortage reductions of up to 2,240 of at the coal-gas plant could be achieved. Further reductions in shortages could be achieved if storage water were also made available to agricultural users. Table 2-8 Elkhead Reservoir Operational Flow Targets for the Yampa River at Maybell (cfs) October 204 November 255 December 228 January 217 February 256 March 498 April May June July 400* August 220 September 200* * Different from preliminary flow recommendation Reservoir Levels I Figure 2-3 shows the end-of-month contents of the three modeled reservoirs. Note that the relative positions of the lines on this graph are changed from previous scenarios; the topmost line now represents the enlarged Elkhead Reservoir contents. Storage levels in Stagecoach and Steamboat Lake are similar to the "without project" 1 scenario. Stagecoach cycling is dominated by winter releases for hydropower and environmental purposes with some additional draft in 1934 for municipal water supply purposes. The enlarged Elkhead Reservoir exhibits substantial seasonal cycling in storage contents under this scenario due primarily to flow support releases made during the.months of July through March. These releases average 16,700 of per year and the entire flow support pool is released in many years. Existing and transferred storage contracts are utilized only during the dry years of the study period; in most years these pools remain full. The annual maximum drawdown typically occurs during the winter months and averages approximately 21 feet. Average drawdown at the end of August is less than the 10 feet previously considered as a recreational constraint. i 1 2_20