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• Board Meeting Date: 7/11/2007
• Description: ISF Section - Willow Creek and Beaver Creek New Appropriations in Moffat County
• Board Meetings - Doc Type: Memo

Instream Flow Recommendation(s)
The BLM has recommended 1.8 cfs, summer, and 1.1 cfs, winter, based on its data collection
efforts (see Table 1 and Appendix). The modeling results from this survey effort are within the
confidence interval produced by the R2CROSS model.

Land Status Review

Total Length Land Ownership
Upper Terminus Lower Terminus (miles) % Private % Public
2 Bar Creek Utah Border 5.2 0% 100%

79% of the public lands are owned by the BLM and 17% of the public lands are owned by the
Colorado State Land Board.

Biological and Field Sm'Vcy Data
The BLM and CDOW have 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 BLM to
the CWCB "Beaver Creek is classified as a small, high gradient stream with a stable channel and
large substrate. Cover, woody debris, water temperatures, and aquatic insect density are excellent
for supporting salmonid populations. Fishery surveys indicate the stream environment supports
self-sustaining populations of mottled sculpin, brook trout, and Colorado River Cutthroat Trout."
(See Fish SUlvey in Appendix).

Field Sm"vey Data
BLM 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. The appendix 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 BLM 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 the stream, two data sets were collected with the results shown in Table 1
below. Table 1 shows who collected the data (Party), the date the data was collected, the
measured discharge at the time of the survey (Q), the accuracy range of the predicted flows