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I 1941 Dolores snowmelt hydrograph. Following operating procedure for McPhee Reservoir, I maximum releases for downstream channel capacity were made in advance of Ihc forecasted snowmelt runolT. Outflow was then set equal to inllow, for the mosl part, until the inl1o\\' hydrograph exceeded 4,000 cfs. Maximum rclcase was then limited to 4,000 cfs until storage began 10 drop. During actual operation based on snowmelt forecasts, the reservoir operalor can begin to cut back on releases as early as June to till the reservoir. The resclV'oir operation was not simulated this way for the rain-an-snow hydrograph in June 1949. Based on a large snowmelt forecasl, an advance release of 4,000 cfs was made: Ihcn the outflo\\' releases were made equal to inllow. When the rain40n4snow hydrograph exceeded 4,000 cfs, the outl1ow was limited to 4,000 cfs until storage dropped. This hydrograph was routed through McPhee Reservoir without exceeding the SO cfs release rate of change or 4,000 cts release dO\\'Tlstream. For reservoir simulation purposes, the snO\....melt hydrograph of 1941 was considered as the 1% chance snowmdt event; the rain-an-snow hydrograph of June 1949 was treated as the 1% chance rain-on-snO\.... hydrograph. Information on Ihe simulated McPhee Reservoir routings is presented in Table 22. "llIe simulated reservoir operations arc displayed graphically on Plate 24 for the May 1941 snowmelt evcnt and on Plate 25 for June 1949 rain-an-snow event. Table 22 Simulated Reservoir Operation for the I % Peak Flow Enol '\lcPhee Dam and Reservoir, Colorado Inflow Data ReservoirParamclers Peak .\laximum \1aximum ype of Even I Source Release Downstream lnllow Storage Stage Rate ofChan"c Channel Canacit . Ram-on-snO\~ Observed 50cfslhr ~,OOOcfs 8,l-Wcfs J74,356ac-ft 6,922,47 fI 1949 Sno\\melt Observed 50cf!i/hr 4.000cfs 8.070cfs 381.107ac-ft 0.923.98 ft 1941 Rainllood H:-'I$ Fl000 1000 cfslhr 5,OOOcfs 12,J20cfs 381.024 ac-ft 6.924.00 ft Hydrograph 41