BOARD01443

• Board Meeting Date: 5/21/2001
• Description: ISF Section - CWCB Instream Flow Quantification Program
• Board Meetings - Doc Type: Memo

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Staff Recommendation
The CWCB staff recommends that the CWCB adopt the following policy for considering future biologic
ISF recommendations: .

With regard to the development of biologic ISF recommendations, the Colorado Water
Conservation Board hereby detelmines that:
1) the R2CROSS methodology, as described by Nehring (1979) and Espegren (1996), provides
reasonable protection of the natural environment, as required by 37-92-102;
2) the standard level of biologic instream flow protection that is appropriate for coldwater.
streams within the State of Colorado shall be that amount which results from averaging the
biologic recommendations of single/multiple R2CROSS transects on a particular stream
segment;
3) the Board will consider providing a greater level of protection than the amount which
results from the single/multiple R2CROSS transect approach on stream reaches. where
significant evidence warrants an additional level of flow protection, and
4) due to the complex nature of the biologic, social, and political considerations associated
with cool and wann water instream flow it will continue to evaluate biologic instream flow
recommendations for cool and wann water streams on a case-by-case basis.

Literature Cited
Espegren, G.D. 1996. Development of Instream Flow Recommendations in Colorado Using R2CROSS.
Colorado Water Conservation Board. Denver, CO.

Nehring, R.B. 1979. Evaluation of instream flow methods and detennination of water quantity needs for
streams in the State of Colorado. Colorado Division of Wildlife. Fort Collins, CO.

Tennant, D.L. 1976. Instream Flow Regimens for Fish, Wildlife, Recreation and Related Environmental
Resources. Fisheries Vol. 1 No.4.

ISF Quantification Policy Paper S.doc

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