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

for over 80 years (Anderson 1997). Assuming that future Recovery Program activities
(construction of fish passage facilities, razorback sucker stocking and bottomland
restoration) are successful in repopulating the reaches between and above the diversions
with razorback sucker and Colorado pikeminnow, flow regimes suitable for these fish will
need to be provided. This report provides initial recommendations for suitable flow regimes
during the summer and winter periods based on the best scientific information, historic
conditions, and extrapolation from similar reaches, as discussed in the RIPRAP (see above).
Refinement of summer and winter recommendations will require additional site-specific field
research. However, for the spring period (April-July), site-specific research has already
been conducted and the relevant findings are incorporated in this report and no additional
studies to further refine spring recommendations are anticipated. Hence, this report
identifies flow regimes needed by the fish during spring and provides interim
recommendations for summer and winter. In doing so, needs of the fish within these
reaches are considered as well as those of fish downstream, also affected by such flows.
Background
The Grand Valley Irrigation Company Diversion Dam (GVICDD), at the top of the
15-mile reach, was constructed in 1883 and supplies water to the Grand Valley Canal (Fig.
1). Only 0.9-1.2 m (3-4 feet) high, it blocked upstream movement of fishes only during
periods of low flow. The Bureau of Reclamation (USBR) modified this structure in 1998 to
allow passage during all but the very lowest flows (Burdick 1999). A second diversion
structure, the Price-Stubb dam, was constructed in 1911 three miles farther upstream; it.
stands 3 m (10 ft) high and blocks upstream movement of fish at all flow levels. However,
water is no longer diverted at this structure. A Colorado pikeminnow implanted with a
radio-tag in the 15-mile reach was tracked upstream of GVICDD to the base of the Price-
Stubb Dam two summers in a row (Osmundson and Kaeding 1989), and several adult
Colorado pikeminnow have been captured in this 5-km (3-mile) reach in recent years
(USFWS unpublished data). A third dam, the Grand Valley Project Diversion Dam
(GVPDD), is located about 8 km (5 miles) upstream of the Price-Stubb dam. This dam,
2