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<br />Table I: Data
<br />
<br />Partv Date Q 250%-40% Summer (3/3) Winter (2/3)
<br />WWE/QR 11117/98 3,99 10,0 - 1.6 9,1 1.4(1)
<br />
<br />www = WW Wheeler QR = Queen of the River
<br />(1) Predicted flow outside of the accuracy range of Manning's Equation.
<br />
<br />? = Criteria never met in R2CRQSS Staging Table.
<br />
<br />Biologic Flow Recommendations
<br />The BLM recommended a 13,0 cfs summer flow and a 4,5 cfs winter flow based on their April
<br />17th, 1996, data collection effort, An alternative flow recommendation was proposed by the City
<br />of Cripple Creek and Cripple Creek/Victor Mining Company based on additional data collected
<br />by WWW/QR, of 6,0 cfs, April 1 through July 31 and 4,25 cfs, August 1 - March 31. The
<br />WWW/QR flow recommendations were based on an adjustment of the CWCB/CDOW 1 ftIsec
<br />velocity criteria standard for summer flows down to 0,8 ft/sec (See WWW/QR Executive
<br />Summary). The CWCB tabled action on this flow recommendation until CWCB staff could
<br />review the additional data collected by WWE/QR and to collect additional data, if necessary,
<br />
<br />Staff reviewed the data collected by WWE/QR, The summer flow recommendation, which met
<br />3 of3 criteria and was within the accuracy range of the R2CROSS model, was 9,1 cfs (See Table
<br />I), The winter flow recommendation, which met 2 of 3 criteria but was outside of the accuracy
<br />range of the R2CROSS model, was 1.4 cfs (See Table 1), It is the belief of CWCB staff that
<br />winter recommendations that fall outside of the accuracy of the model, below 40% of the
<br />measured discharge, may underestimate the required winter flow, To determine the winter flow
<br />recommendations, staff looked at valid winter flow recommendations for the stream segments
<br />above Trail Gulch (4,5 cfs) and below Felch Creek (5,0 cfs) and considered the winter
<br />recommendations offered by the BLM (4,5 cfs) and WWE (4,25 cfs), After consulting with the
<br />Colorado Division of Wildlife staff believes 4,75 cfs will be sufficient to protect the natural
<br />environment to a reasonable degree,
<br />
<br />Hydrologic Data
<br />
<br />After receiving the cooperating agencies' 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 was derived from data collected by the USGS
<br />stream gage for Fourmile Creek below Cripple Creek (10 #07096250), which has a drainage area
<br />of 272 square miles (see Gage Summary in Appendix C), The period of record for this gage is
<br />1992 to present, the period of record used by staff in their analysis was 1992 - 1997, or five years
<br />of record, To estimate the flow of Fourmile Creek at Trail Gulch, staff used the measured flow
<br />at the USGS gage and added the estimated inflow from the Carlton Tunnel, approximately 2,8
<br />cfs, to all values (1), Table 2 below displays the estimated flow of Fourmile Creek at the
<br />confluence with Trail Gulch, in terms of a percentage of exceedence, The orange shading
<br />highlights how often the summer flow has been available and the blue shading highlights how
<br />often the winter flow has been available,
<br />
<br />(I) According to WW Wheeler, Engineers for Cripple Creek and Victor Gold Mine, the Carlton Tunnel is currently
<br />flowing at rates of 2,8 cfs to 3,5 cfs
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