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<br />Table I: Data
<br />
<br />Party Date Q 250% -40% Summer (3/3) Winter (2/3)
<br />DOW/CWCB 10/20/1998 1.8 4.5 - 0.7 3.8 0.5")
<br />
<br />BLM = Bureau of Land Management DOW = Division of Wildlife
<br />(1) Predicted flow outside of the accuracy range of Malll1ing's Equation.
<br />
<br />CWCB = Colorado Water Conservation Board
<br />? = Criteria never met in R2PRUDEN Staging Table.
<br />
<br />Biologic Flow Recommendation
<br />The summer flow recommendation, which met 3 of 3 criteria and was within the accuracy range
<br />of the R2CROSS model, is 3.8 cfs (See Table I). The winter flow recommendation, which met 2
<br />of 3 criteria but was outside the accuracy range of the R2CROSS model, is 0.5 cfs (See Table I).
<br />However, the CDOW believes that the winter flow recommendation of 0.5 cfs will be sufficient
<br />to protect the natural environment to a reasonable degree.
<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 Iron Creek near Crawford, CO (ID #09129500), which has a drainage
<br />area of 71.5 square miles (See Gage Summary in Appendix C). The total drainage area of this
<br />segment of Muddy Creek is approximately 23 square miles. The period of record for this gage
<br />was 1947 to 1952, the period of record used by staff in their analysis was 1947 - 1952, or six
<br />years of record. Table 2 below displays the estimated flow of Muddy Creek at the gage, in terms
<br />of a percentage of exceedence.
<br />
<br />Table 2: Estimated Stream Flow in Muddy Creek
<br />Exceedences jan feb mar Apr may Jun jul aug sep oct nov dec
<br />10/0 5,2 S,9 1S,2 26,S 21,S 26,0 25,0 13,6 13,1 22,3 6,2 6,7
<br />50/0 4,6 5,2 11,5 1S,7 19,1 17,7 16,3 6,2 5,S 7,2 5,S 4,9
<br />10% 4,2 4,5 S.4 14,9 17,2 15,6 14,3 4,5 4,9 6,5 4,5 4,5
<br />SO% 2,S 2,7 2,S 4,9 6,S 7,S 3,9 2,7 2,0 2,3 3,0 2,9
<br />90% 2,6 2,6 2.4 2,1 5,5 6,5 3,2 2,1 1,3 2,1 2,S 2,S
<br />95% 2,3 2.4 2,1 1,S 4,5 4,9 3,0 1,S 1,2 1,7 2.4 2,6
<br />99% 2,1 2,0 1,9 1,6 3,1 3,3 2,5 1,5 1,0 1.4 1,9 2,0
<br />
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