4-06CW231 Coal Creek Supplemental Data

• Case Number: 06CW0231
• Stream Name: Coal Creek
• Watershed: Gunnison
• Water Division: 4
• Water District: 40
• County: Gunnison
• Instream Flow App - Doc Type: Supplemental Data

Land Status Review
Upper Terminus
Lower Terminus
Total Length
(miles)
Land Ownership
% Private
% Public
Little Gunnison
Creek
Anthracite Creek
4.8
4%
96%
96% of the reach is located on public lands managed by the USFS and the other 4% of the reach
is located on private lands.
Biological and Field Survey Data
The CDOW has conducted field surveys of the fishery resources on this stream and have found a
natural environment that can be preserved. As reported in the letter from CDOW to the CWCB
"Coal Creek is classified as a river (between 60 to 99 feet wide) and fishery surveys indicate the
stream environment of Coal Creek supports a self - sustaining brown and rainbow trout fishery.
Coal Creek also supports populations of mottled sculpins, dace and blue head suckers" (See
CDOW Fish Survey in Appendix B).
Field Survey Data
CDOW staff used the R2CROSS methodology to quantify the amount of water required to
preserve the natural environment to a reasonable degree. The R2CROSS method requires that
stream discharge and channel profile data be collected in a riffle stream habitat type. Riffles are
most easily visualized, as the stream habitat types that would dry up first should streamflow
cease. This type of hydraulic data collection consists of setting up a transect, surveying the
stream channel geometry, and measuring the stream discharge. Appendix B contains copies of
field data collected for this proposed segment.
Biological Flow Recommendation
The CWCB staff relied upon the biological expertise of the cooperating agencies to interpret
output from the R2CROSS data collected to develop the initial, biologic instream flow
recommendation. This initial recommendation is designed to address the unique biologic
requirements of each stream without regard to water availability. Three instream flow hydraulic
parameters, average depth, percent wetted perimeter, and average velocity are used to develop
biologic instream flow recommendations. The CDOW has determined that maintaining these
three hydraulic parameters at adequate levels across riffle habitat types, aquatic habitat in pools
and runs will also be maintained for most life stages of fish and aquatic invertebrates (Nehring
1979; Espegren 1996).
For this segment of stream, one data set was collected with the results shown in Table 1 below.
Table 1 shows who collected the data (Party), the date the data was collected (Date), the
measured discharge at the time of the survey (Q), the accuracy range of the predicted flows
based on Manning's Equation (240% and 40% of Q), the summer flow recommendation based
on meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3
hydraulic criteria.
Table 1: Data
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