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Reservoir Operating Studies case of Stagecoach Reservoir, winter releases for power generation and environmental purposes. Instream Flow Conditions Flows below Stagecoach Reservoir reflect hydropower and environmental releases from that facility. These operations tend to produce more uniform flow conditions year around, with only slightly elevated (on the average) flows during the runoff period. Streamflow conditions below Steamboat Lake and Elkhead Reservoirs primarily reflect the spring spilling of inflows, because those reservoirs are full most of the year, and low fall and winter flows because the reservoirs do not presently have minimum release requirements. Note that seepage from Elkhead Reservoir has not been explicitly modeled. Table 2-6 shows modeled flow conditions at the Maybell gage. The seasonal dependence on snowmelt runoff is clearly evident, as are the late season effects of upstream depletions. Note that the occurrences of zero flow are an artifact of the modeling process; in reality, the Maybell Canal diversion dam just upstream of the gage reach exhibits some leakage that keeps a small amount of flow in the river (5-10 cfs); this seepage phenomenon was not represented in the basin model. Flow conditions at the Maybell gage site can be used as a general indicator of Yampa River flow conditions in occupied habitat above the confluence with the Little Snake River, though there are reach gains and return flows which accrue below the Maybell gage. Table 2-5 presents a statistical summary of modeled flow conditions at Maybell that can be compared to the preliminary flow recommendations. Noteworthy are the low flows in late summer and fall months. In the drier quartile of years (those having a 75 % flow exceedance probability), flows in this reach drop to very low levels as the senior Maybell Canal diversion just upstream takes nearly everything in the river. Comparison to Table 2-4 (the preliminary flow recommendations at Maybell) shows that, under current conditions, the median flows satisfy the flow recommendations in all months. More detailed results of this scenario can be found in Appendix E. Table 2-5 Modeled Current Conditions Flows at Maybell (cfs) Month 25% exc. 50ya exc. 75% exc. October 317 234 162 November 364 275 228 December 338 247 198 January 304 235 198 February 352 277 255 March 726 513 406 April 3,136 2,102 1,396 May 7,028 5,772 4,069 June 6,385 5,176 3,657 July 1,772 1,018 469 August 387 237 107 September 180 112 44 2-14