BOARD00154 ‎(2)‎

• Board Meeting Date: 3/13/2007
• Description: ISF Section - Notice of 2008 Instream Flow Recommendations and Summary of ISF Workshop
• Board Meetings - Doc Type: Memo

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The information contained in this report and the associated appendices serves as the basis
for the instream flow recommendation to be considered by the Colorado Water
Conservation Board (Board). It is the professional opinion ofthe staff of both Trout
Unlimited (TU) and the Colorado Division of Wildlife (CDOW) that the information
described in these documents is sufficient for the Board's staff to begin the investigations
required to establish an instream flow appropriation under Rule 5 i of the Instream Flow
Rules.

Bear Creek originates in a saddle between Mount Garfield and Almagre Mountain, west
of Colorado Springs (Figl). The stream flows generally eastward towards Colorado
Springs and its confluence with Fountain Creek. This recommendation covers a perennial
reach stretching from Bear Creek's headwaters at approximately 10,400 feet to just above
the Bear Creek Pipeline diversion at 6,500 feet, a distance of approximately 5.6 miles. Of
this length approximately 42 % (2.3 miles) traverses lands held by Colorado Springs
Utilities, 38% (2.1 miles) flows through U.S. Forest Service land and the remaining 20%
(1.1 miles) flows through Bear Creek Canyon Park (Table 1). The stream does not run
through any private land.

Table 1: Bear Creek Land Status Review
Total length
U er Terminus lower Terminus miles % Private
Headwaters Above Diversion 5.6 0.0%

%State
20%

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Instream Flow Recommendations
TU and CDOW are recommending instream flow appropriations of 1.8 cfs during the
summer (4/15 - 8/15), 1.3 cfs during the fall (8/16 - 10/31) and 0.75 cfs during the winter
(1111 - 4/14). These recommendations are based on the physical and biological data
collected to date and incorporate water availability constraints. An R2CROSS analysis of
cross-sectional data collected on 8/10//06 was relied on to develop these
recommendations (Table 2). Three in stream flow hydraulic parameters, average depth,
percent wetted perimeter, and average velocity, are used to develop biologic instream
flow recommendations. The CDOW has determined that by maintaining these three
hydraulic parameters at adequate levels across rime 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). Although most of the modeling results from this effort
were within the confidence interval produced by the R2CROSS model (Appendix B), the
estimate of minimum in stream summer flows from the first cross section was above the
upper confidence interval and was therefore set to the value of this confidence interval.

T bl 2 B

C k R2C

s

a e . ear ree ross ummary
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Confidence Interval (cfs) Recommended Flows. (efs)
Party Date a (efs) 250%-40% Summer (3/3) Winter (2/3)
TU 8/10/2006 0.87 2.2 - 0.3 2.2** 0.93
TU 8/10/2006 0.99 2.5 - 0.4 1.31 0.57

. Recommendations based on meeting specified number of hydrologic criteria (average depth. percent wetted
perimeter and average velocity).

.. Estimate of 2.35 ets was abvoe Upper Confidence Inerval. so it was assigned maximum value of 2.2 ets.

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