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<br />downstream of several upstream water rights that affected the flow measurements, so the gage <br />readings cannot be accurately apportioned to the remainder of the watershed. <br /> <br />The closest gage CWCB staff found which could be used to estimate the flow of Horsefly Creek <br />was the gage located on Maverick Draw near Norwood, this drainage basin is located south of <br />the Horsefly Creek drainage. The hydrograph was derived from data collected by the USGS <br />stream gage for Maverick Draw near Norwood, CO (10 #09175400), which has a drainage area <br />of 41.3 square miles. The drainage area of Horsefly Creek is approximately 110 square miles. <br />Staff used a basin apportionment method to estimate stream flows for Horsefly Creek (See Gage <br />Summary in Appendix C). The period ofrecord for this gage was 1975 to 1988, the period of <br />record used by staff in their analysis was 1975 - 1980, or 5 years of record. Table 2 below <br />displays the estimated flow of Horsefly Creek uptream of the San Miguel River, in terms of a <br />percentage of exceedence. <br /> <br />Table 2: <br /> <br />Exceedences Janus'" Februa'" March Anril Ma" June JUN Aunust Sentember October November December <br />1% 47.54 T 46,82 T 35,82 25,41 57.05 172,06 62,38 29,61 27,11 10.39 9.69 <br />5% 8.66 21,04 25,30 18,84 37,29 53,27 50,61 24,77 18,84 9.85 8.79 9.19 <br />10% 7.72 14,38 21,71 14,65 29,30 47,94 42,62 22,32 13,85 8.79 8.52 8.26 <br />20% 7.19 15,18 10.39 18,00 42,62 31.96 17,58 7.72 7.99 7.99 6.13 <br />50% 4.53 6.39 6.79 6.13 6.92 26,63 15,18 8.26 4.79 4.00 4.26 4.00 <br />80% 3.20 3.46 4.26 3.46 2.66 S.6S 2.93 2,02 0.80 1.49 1.70 <br />90% 1.49 1.81 3.46 2.93 1.98 T 0.93 0.60 0.32 0.35 0.56 1,17 1,38 <br />95% 1.38 1.61 2.93 2.13 1.63 0.75 0,59 0.29 0.29 0.40 0.93 1.07 <br />99% 1.12 1.43 1.60 2.02 0.79 0.53 0.48 0.19 0.26 0.31 0,80 0.97 <br /> <br />Horsefly Creek Estimated Stream Flow <br /> <br />30 <br />25 <br />20 <br />orJ 15 <br />10 <br />5 <br />o <br /> <br /> <br /><t.z ~..('-. <br />~ '<9 <br /> <br />~~ "9~ ~)- VV1- V<f <br /> <br />"9(/. \S'~'" 00 1-0 O~ <br />Q^J /0 '/.--'0 <br /> <br />Month <br /> <br />Table 2 shows that the summer recommendation of 13.1 cfs is only available at least 50% of the <br />time from June 15th to July 14th. Table 2 also shows that the winter flow recommendation of <br />10.5 cfs is not available at least 50% of the time for any month. The winter recommendation <br />was reduced to 3.25 cfs for the time periods of July 15th through June 14th based on limited water <br />availability. <br /> <br />- 5 - <br />