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<br />Table 1: Data
<br />
<br />Party Date Q 250% -40% Summer (3/3) Winter (2/3)
<br />CD OW 08/21/1980 45.3 113 -18.1 36.1 33.7
<br />CD OW 10/29/1985 74.6 187 - 29.8 96.0 66.0
<br />CD OW 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 />(1) Predicted flow outside of the accuracy range of Malll1ing's Equation. ? = Criteria 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 Nov Dee
<br />10/0 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 />50/0 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 1444,01400,0 465,0 82,5 38,0 27,0 26,0 21,0
<br />
<br />
<br />80%
<br />90%
<br />95%
<br />99%
<br />
<br />15,0
<br />14,0
<br />14,0
<br />12,2
<br />
<br />16,0
<br />15,0
<br />14,0
<br />13,0
<br />
<br />21,0
<br />20,0
<br />19,0
<br />18,0
<br />
<br />41,0
<br />32,0
<br />28,0
<br />25,2
<br />
<br />263,2 585,0
<br />217,0 225,0
<br />182,0 191,0
<br />162,7 141.4
<br />
<br />39,0
<br />24,5
<br />23,0
<br />21,0
<br />
<br />22,0
<br />19,0
<br />18,0
<br />16,0
<br />
<br />20,0
<br />19,0
<br />18,5
<br />17,0
<br />
<br />17,0
<br />17,0
<br />16,0
<br />14,0
<br />
<br />17,0
<br />16,0
<br />15,0
<br />15,0
<br />
<br />16,0
<br />15,0
<br />14,0
<br />12,5
<br />
<br />-4-
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