8214

• UCREFRP Catalog Number: 8214
• Author: Modde, T., D. Irving and R. Anderson.
• Title: Habitat Availability and Habitat Use of Endangered Fishes in the Yampa River during Baseflow Periods.
• USFW Year: 1997.
• USFW - Doc Type: Vernal, Utah and Grand Junction, Colorado.
• Copyright Material: NO

INTRODUCTION

The Yampa River is the largest tributary in the Upper Colorado River Basin that has a
relatively natural hydro graph with flows resembling historical magnitude (Tyus and Karp 1989).
Yampa River flows are highly variable annually with spring runoff peaks greater, and summer
base flows lower than the Green River into which it empties (USGS records). Self sustaining
populations of the endangered Colorado squawfish Ptychocheilus /ucius (Tyus 1990) and one of
five known endangered humpback chub Gila cypha populations (Karp and Tyus 1990) reside in
the Yampa River. In addition, this river contains one each of only two know spawning sites of
Colorado squawfish and razorback sucker Xyrauchen texanus (Tyus and Karp 1990). Because
most Colorado squawfish spawned in the Yampa River drift downstream to nursery sites in the
Unitah Basin, these offspring are important in defining squawfish recruitment in the Middle
Green, White, and Yampa rivers. Despite, or because of, highly variable environmental
conditions, native fishes are more abundant than nonnative fishes in the lower Yampa River
(Modde and Smith 1995).

In 1995, the Colorado Water Conservation Board filed on water rights to protect the
natural environment and habitats of endangered fish in the Yampa River (Case numbers
95CW156 and 95CW155, filed December 28, 1995). Since these water rights will be junior to
existing rights, they will only influence future water development. Existing instream flows in the
Yampa River appear to be adequate to maintain low but stable populations of Colorado
squawfish and humpback chub (Tyus and Karp 1989). However, in some years, for example
1994, stream flows can be very low (approx. 10 cfs). The frequency and duration oflow flow
periods are expected to increase with continued water development until the state of Colorado
develops its full allotment according to the Upper Colorado River Compact agreement. Because
limited opportunities currently exist to store spring runoff waters, the greatest opportunity for
water depletion occurs during the low flow periods of the year, exacerbating potential low flow
impacts on fish.

, If the anticipated frequency of low instream flows cannot provide adequate protection of
endangered fish, it is incumbent upon the participants of the Recovery Implementation Program
for the Recovery of the Endangered Fishes of the Upper Colorado River Basin (RIP) to provide
alternatives for the recovery of affected listed species. Options to provide adequate flow
protection include purchasing and converting existing senior water rights to instream flow rights,
or to develop water storage for augmenting flows during the low flow period. Enlargement of
Elkhead Reservoir, on Elkhead Creek, could store up to 25,000 acre feet of water during spring
runoff for flow augmentation in the summer, but would cost nearly 30 million dollars (Maddux,
pers. comm.). However, the benefits of providing baseflow augmentation compared to the cost
of retaining spring high flows for endangered fishes is uncertain.

In an effort to address the future water development and recovery options for endangered
fishes in the Yampa Valley, the RIP initiated the Yampa River Basin Endangered Fish Recovery
and Water Management Plan. The goal of this plan is "to provide water for existing and future

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