9413

• UCREFRP Catalog Number: 9413
• Author: Osmundson, D. B.
• Title: Flow Regimes for Restoration and Maintenance of Sufficient Habitat to Recover Endangered Razorback Sucker and Colorado Pikeminnow in the Upper Colorado River.
• USFW Year: 2001.
• USFW - Doc Type: Grand Junction.
• Copyright Material: NO

completed in 1916, provides water to the Government 9ghline Canal and the Orchard
Mesa Power Canal. It stands 4.3 m (14 feet) high and is also a barrier to upstream
movement of fish at all flow levels. Because of water withdrawal for the Government
Highline and Grand Valley canals, flows during the irrigation season vary considerably
among the three contiguous reaches: the most upstream reach, GVPDD-to-Rifle, has the
most water, the GVICDD-to-GVPDD reach has a moderate amount, and the 15-mile reach
(downstream of GVICDD) has the least. Because no water is removed at the Price-Stubb
Dam, the 5-km (3-mile) segment downstream and the 8-km (5-mile) segment upstream of
this structure experience the same flow regime. Plateau Creek enters the Colorado River
just downstream of GVPDD, but during summer provides a relatively small contribution of
water, averaging 20-60 cubic feet per second (cfs).
Capture records indicate the De Beque-to-Rifle reach has provided important
habitat to razorback suckers up until recent times (Kidd 1977, Valdez et al. 1982, W.
Elmblad, Colorado Division of Wildlife [CDOW], unpublished data). Fish biologist George
Kidd, conducting fish surveys in the mid-1970s, located several hundred spawning
razorback suckers around June 1 in a zero-velocity, 3.2 h (8-acre) pool situated on the
north side of the river just upstream of De Beque, Colorado. More than 70 adults were
caught in trammel nets in two hours and eggs were collected from the substrate (George
Kidd, personal communication). Also, a longtime area fisherman reported that he used to
catch 2-4 "humpback suckers" (razorbacks) per day in a slough just downstream of Rulison
during 1938-1940 (Simon Wadell, personal communication). More recently, a single adult
was captured by CDOW personnel from a riverside pond X9.7 km (6 miles) downstream of
Rifle, Colorado in 1991 and a total of 165 different adults were captured from a pond 1.6
km (1 mile) downstream from the town of De Beque during 1992-1993 (W. Elmblad,
personal communication). These recent observations prompted the U. S. Fish and Wildlife
Service (USFWS) to extend the designation of critical habitat for razorback sucker in the
Colorado River upstream as far as the town of Rifle (USFWS 1994).
No observations are on record that would verify recent or historic use by Colorado
pikeminnow of the two reaches upstream of the Price-Stubb Dam. Extensive surveys in the
mid-1970s (Kidd 1977, G. Kidd, personal communication) and in the early 1980s (Valdez et
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