ISFAPPC03841

• Case Number: 00CW0105
• Stream Name: Fourmile Creek
• Watershed: Fourmile Creek
• Water Division: 2
• Water District: 12
• County: Fremont
• Instream Flow App - Doc Type: Supplemental Data

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of Q), the summer flow recommendation based upon meeting 3 of 3 hydraulic criteria and the
winter flow recommendation based upon 2 of 3 hydraulic criteria.

Table 1: Data

Partv Date Q 250%-40% Summer (3/3) Winter (2/3)
WWW/QR 11/18/98 9.04 22.6 - 3.6 6.7 5.0
DOW/WWW 4/15/99 8.33 20.8 - 3.3 8.7 1.5\1)
BLM 4/17/96 13.95 34.9 - 5.6 13.0 4.5\1)
DOW/WWW 4/16/99 9.08 22.7 - 3.6 2.5(1) 1.9(1)

BLM = BUreau of Land Management DOW = Division of Wildlife WWW = WW Wheeler QR = Queen ofthe River
(I) Predicted flow outside of the accuracy range of Manning's Equation. ? = Criteria never met in R2CROSS Stagmg Table.

Biologic Flow Recommendations
The BLM recommended a 13.0 cfs summer flow and a 4.5 cfs winter flow based on their April
17th, 1996, data collection effort. An alternative flow recommendation, based on additional data
collected by WWW/QR, of 5.25 cfs, April 1 through July 31 and 3.0 cfs, August 1 - March 31,
was proposed by the City of Cripple Creek and Cripple CreeklVictor Mining Company. The
WWW/QR flow recommendations were based on an adjustment of the CWCB/CDOW 1 ftlsec
velocity criteria standard for summer flows down to 0.8 ft/sec (See WWW/QR Executive
Summary). The CWCB tabled action on this flow recommendation until CWCB staff could
review the additional data collected by WWW/QR and to collect additional data, if necessary.

Staff reviewed the data collected by the BLM and WWW/QR and decided to collect two more
data sets, bringing the total number of data sets to review to four. The summer flow
recommendations which met 3 of 3 criteria and are within the accuracy range of the R2CROSS
model fall between 13.0 and 6.7 cfs (See Table 1). Averaging the three summer flow
recommendations gives a summer recommendation of 9.5 cfs. The winter flow recommendation
which met 2 of 3 criteria and was inside of the accuracy range of the R2CROSS model was 5.0
cfs (See Table 1).

Hydrologic Data

After receiving the cooperating agencies' biologic recommendation, the CWCB staff conducted
an evaluation of the stream hydrology to determine if water was physically available for an
instream flow appropriation. The hydro graph was derived from data collected by the USGS
stream gage for Fourmile Creek below Cripple Creek (10 #07096250), which has a drainage area
of 272 square miles (see Gage Summary in Appendix C). The period of record for this gage is
1992 to present, the period of record used by staff in their analysis was 1992 - 1997, or five years
of record. To estimate the flow of Fourmile Creek at Felch Creek and upstream of Wilson
Creek, staff used the measured flow at the USGS gage and added the estimated inflow from the
Carlton Tunnel, approximately 2.8 cfs, to all values and subtracted upstream in-priority
diversions(l). Tables 2 and 3 below display the estimated flow of Fourmile Creek at the
confluence with Felch and Wilson Creeks, in terms of a percentage of exceedence. The orange
shading highlights how often the summer flow has been available and the blue shading highlights
how often the winter flow has been available.

(I) According to W,W. Wheeler, Engineers for Cripple Creek and Victor Gold Mine, the Carlton Tunnel is currently
flowing at rates of 2.8 cfs to 3.5 cfs