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

wide) and fishery surveys indicate the stream environment of Como Creek supports Greenback .
cutthroat trout (Oncorhynchus clarkii stomiJs) (See CDOW Fish Survey in Appendix B).
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Greenback cutthroat trout have been identified by the CDOW and federal agencies as "species of
greatest conservation need". CDOW ha~ been involved in developing a Conservation and
Management Plan for this species (Greenbabk Cutthroat Trout Recovery Plan). The intention of
this plan is to increase populations and dis~butions of identified species, thereby assisting in the
long-term persistence of each species. The ,success of this plan could potentially curtail the need
for federal listing of these species under the Endangered Species Act (ESA). This species is
currently state and federally listed as "Thre~tened".
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Field Survey Data

CDOW staff used the R2CROSS methodblogy to quantify the amount of water required to
preserve the natural environment to a reas6nable degree. The R2CROSS method requires that
stream discharge and channel profile data b~ collected in a rime stream habitat type. Rimes are
most easily visualized, as the stream habitat types that would dry up first should streamflow
cease. This type of hydraulic data colledtion 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 segme~t.
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Biological Flow Recommendation

The Board staff relies upon the biological expertise of the cooperating agencies to interpret
output from the R2CROSS data collect~d to develop the initial, biologic instream flow .
recommendation. This initial recommendation is designed to address the unique biologic
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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 in stream flow recommendations. : The CDOW has determined that maintaining these
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three hydraulic parameters at adequate leve1ls 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).

For this segment of stream, seven data sets were collected with the results shown in Table I
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below. Table 1 shows who collected the data (Party), the date the data was collected, the
measured discharge at the time of the su&ey (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.