Laserfiche WebLink
<br />Biologic Flow Recommendation <br />The summer flow recommendation, which meets 3 of 3 criteria and is within the accuracy range <br />of the R2CROSS model is 4.2 cfs (See Table I). The winter flow recommendation, which meets <br />2 of 3 criteria and is within the accuracy range of the R2CROSS model is 2.9 cfs (See Table I). <br />It is our belief that recommendations that fall outside of the accuracy range of the model, over <br />250% of the measured discharge or under 40% of the measured discharge may not give an <br />accurate estimate ofthe necessary instream flow required. <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 hydro graph below was derived from data collected by the <br />USGS stream gage for Halfmoon Creek near Malta, CO (ID #07083000), which has a drainage <br />area of 23.6 square miles (See Gage Summary in Appendix C). The total drainage area of the <br />Wildcat Gulch Drainage is approximately 3.8 square miles. The period of record for this gage <br />was 1946-1998, the period of record used by staff in their analysis was 1946-1998, or 52 years of <br />record. Table 2 below displays the estimated stream flow of Wildcat Gulch, in terms of a <br />percentage of exceedence. <br /> <br />Table 2: Estimated flow Wildcat Gulch. <br /> <br />Exceedences <br />1% <br />5% <br />10% <br />20% <br />50% <br />80% <br />90% <br />95% <br />99% <br /> <br />Januarv Februarv March Aoril Mav June Julv Auaust Seotember October November December <br />1.45 1.29 1.77 4.19 25.75 47.18 47.66 21.58 8.07 4.19 3.06 1.61 <br />1.11 1.00 1.13 2.58 19.00 38.64 31.95 13.20 5.47 3.22 2.09 1.42 <br />0.90 0.84 0.97 2.09 14.65 33.81 26.08 9.93 4.67 2.90 1.77 1.22 <br />0.81 0.72 0.72 1.38 11.27 28.82 19.00 7.41 3.86 2.25 1.48 1.03 <br />0.61 0.56 0.56 0.90 5.96 19.00 11.27 4.83 2.58 1.61 1.11 0.77 <br />0.48 0.43 0.42 0.56 2.25 12.72 6.76 3.22 1.93 1.21 0.87 0.63 <br />0.40 0.38 0.37 0.43 1.48 10.31 5.15 2.74 1.61 1.08 0.79 0.56 <br />0.34 0.32 0.24 0.39 1.11 8.69 4.19 2.42 1.42 0.98 0.71 0.52 <br />0.24 0.27 0.19 0.27 0.79 5.57 3.08 1.93 1.13 0.82 0.55 0.43 <br /> <br />Wildcat Gulch Estimated Stream Flow <br /> <br /> 5 <br /> 4 <br /> 3 <br />~ <br />u 2 <br /> 1 <br /> :;,- <br /> 0 <br /> "" <br /> <br /> <br /> <br />co, <br /> <br />M'" <br /> <br />,e" <br /> <br />M" <br /> <br />,c, <br /> <br />,cc <br /> <br />,co <br /> <br />,oe <br /> <br />en <br /> <br />'" <br /> <br />ceo <br /> <br />Month <br /> <br />-4- <br />