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<br />. <br /> <br />. <br /> <br />. <br /> <br />... <br /> <br />Table 1: Data <br /> <br />Party Date Q 250%-40% Summer (3/3) Winter (2/3) <br />CDOW 08/21/1980 45.3 113 - 18.1 36.1 33.7 <br />CDOW 10/29/1985 74.6 187 - 29.8 96.0 66.0 <br />CDOW 10/21/1998 28.2 70.4 - 11.3 31.3 16.8 <br /> <br />BLM = Bureau of Land Management DOW = Division of Wildlife <br />(I) Predictcd !low outside of the accuracy range of Manning's Equation ~ = Critcria never met in R2CROSS Staging Table. <br /> <br />Biologic Flow Recommendation <br />The summer flow recommendations, which meet 3 of 3 criteria and are within the accuracy range <br />of the R2CROSS model, range from 96 cfs to 31.3 cfs (See Table 1). The winter flow <br />recommendations, which meet 2 of 3 criteria and are within the accuracy range of the R2CROSS <br />model, range from 66 to 16.8 cfs (See Table 1). Averaging the three summer flow <br />recommendations within range, results in a 54 cfs recommendation. Averaging the three winter <br />flow recommendations within range, results in a 39 cfs recommendation. <br /> <br />Hydrologic Data <br /> <br />After receiving the cooperating agency's biologic recommendation, the CWCB staff conducted <br />an evaluation of the stream hydrology to determine if water was physically available for an <br />instream flow appropriation. The hydrograph below was derived from data collected by the <br />USGS stream gage for Anthracite Creek near Somerset, CO (ID #09132050), which has a <br />drainage area of 94,6 square miles (See Gage Summary in Appendix C). The total drainage area <br />of this segment of Anthracite Creek is approximately 132 square miles. The period of record for <br />this gage was 1977-1981, the period of record used by staff in their analysis was 1977-1981, or 5 <br />years of record. Table 2 below displays the stream flow of Anthracite Creek, in terms of a <br />percentage of exceedence. <br /> <br />Table 2: Estimated Stream Flow on Anthracite Creek <br />Exeeedenees Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nav Dee <br />1% 31.8 30.6 170.4 617.6 3380.0 1690.0 855.6 109.3 50.5 43.5 32.8 26.8 <br />5% 21.0 23.0 63.0 505.0 1622.0 1560.0 536.0 91.8 44.0 30.5 26.0 21.8 <br />10% 20.0 22.0 48.2 466.0 1444.0 1400.0 465.0 82.5 38.0 27.0 26.0 21.0 <br />20% 19.0 20.0 38.0 350.0 1082.0 1150.0 350.0 72.0 32.0 25.0 24.0 20.0 <br />50% 17.0 17.0 27.0 190.0 622.0 938.0 138.5 41.0 25.0 20.0 20.0 19.0 <br />80% 15.0 16.0 21.0 41.0 263.2 585.0 39,0 22.0 20.0 17.0 17.0 16.0 <br />90% 14.0 15.0 20.0 32.0 217.0 225.0 24.5 19.0 19.0 17.0 16.0 15.0 <br />95% 14.0 14.0 19.0 28.0 182.0 191.0 23.0 18.0 18.5 16.0 15.0 14.0 <br />99% 12.2 13.0 18.0 25.2 162.7 141.4 21.0 16.0 17.0 14.0 15.0 12.5 <br /> <br />- 4 - <br />