WSP04165

• File Number: 8240.200.10.B
• Description: UCRBRIP - Riverine Fish Flow Investigations
• Basin: Colorado Mainstem
• Date: 6/1/2003
• Author: CDOW
• Title: Riverine Fish Flow Investigations 2003
• Water Supply Pro - Doc Type: Publication

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bluehead sucker habitat would become unsuitable long before dace habitat loss would
become problematic. Therefore. meso-habitat availability for speckled dace and another
small-bodied native fish, the mottled sculpin (Coitus bairdi) were not modeled in this
study. It was necessary, however. to include these species in an ancillary analysis
because the dace and sculpin populations have been noticeably impacted on the Yampa
River during low-flow scenarios.

Study Objectives:

I). Quantify fish habitat on warm water sections of the Yampa, Colorado and
Dolores rivers using 2-D flow models

2). Determine community structure, density and biomass for fish assemblages
for the three study rivers

3). Determine relationships between habitat availability and fish abundance for
the native species bluehead sucker. flannel mouth sucker and roundtaiJ chub

4). Develop biologically based instream flow recommendations for the Yampa
River and Colorado Rivers in the 15-mile reach

5) Provide validation for meso-habitat suitability values used in the 2-D model
and for predicting habitat as a function of flow

STUDY AREA

Yampa River

There are three study areas on the Yampa River. The two sites established in
1998 are called the Sevens and Duffy stations. A third site at Lily Park was added in
2000. The Sevens station is located at River Mile (RM) 63 and is 1.8 mile in length.
Duffy is at River Miler (RM) 109 and is 1.3 miles in length (Figure I). Sevens and Duffy
were electro-fished in 1998, 1999,2000 and 2001. The habitat was mapped in 1999. The
Lily Park site is located just below Cross Mountain Canyon and just above the mouth of
the lillie Snake River (Figure I). The Lily Park site extends 19 miles from RM 52.7 to
RM 54.5. The bridge on County Road (CR) 25 is located at RM 52.5.