8251

• UCREFRP Catalog Number: 8251
• Author: Rakowski, C. L. and J. C. Schmidt.
• Title: The Geomorphic Basis of Colorado Squawfish Nursery Habitat in the Green River Near Ouray, Utah.
• USFW Year: 1996.
• USFW - Doc Type: #93-1070,
• Copyright Material: NO

Draft Final Completion Report to UDWR for Contract #93-1070, Amendment 3

between 1983 and 1986 caused some channel widening, Mayers and Schmidt (1994) found that these post-Flaming
Gorge Dam floods did nO[ widen the channel to pre-dam conditions.
The invasion of saltcedar (Tamarix chinensis) has probably exacerbated channel narrowing. This exotic
species has dominated much of the riparian community in the Colorado River basin (Graf, 1978). Vegetation. such as
saltcedar, can be an important factor in channel narrowing (Friedman and others, 1996). Vegetation stabilizes bank
deposits with its roots and colonizes within-channel sand deposits, the latter causing additional deposition by vertical
accretion (Friedman and others, 1996). While Graf (1978) believed that the saltcedar invasion was responsible for a
large degree of channel narrowing on the Colorado River prior to the 1950s, Fisher and others (1983, cited in Stanford,
1994) provided evidence that the unregulated Yampa River did not narrow after saltcedar invasion. Fisher and others
(1983) argued that if a river's peak discharges are insufficient to scour and remove young saltcedar, deposits become
stabilized. and the added roughness slows water velocities and causes additional sediment deposition. Along the Green
River in the Uinta Basin. a new saltcedar-covered floodplain. formed in response to flow regulation by Flaming Gorge
Dam, is inset against a higher terrace dominated by cottonwoods (Mayers and Schmidt, 1994).

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