8221

• UCREFRP Catalog Number: 8221
• Author: Van Steeter, M. M.
• Title: Historic and Current Processes Affecting Channel Change and Endangered fish Habitats of the Colorado River Near Grand Junction, Colorado.
• USFW Year: 1996.
• USFW - Doc Type: Doctor of Philosophy.
• Copyright Material: NO

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Van Steeter, Mark M. (Ph.D., Geography)
Historic and Current Processes Affecting Channel Change and Endangered
Fish Habitats of the Colorado River near Grand Junction, Colorado
Thesis directed by John Pitlick

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The goals of this research were to: 1) quantify historic changes in
channel morphology of the Colorado River near Grand Junction,
Colorado and relate these changes to habitats of the endangered Colorado
squawfish(Ptychocheilus lucius); 2) examine the impact of water
development on the flow regime, since flows largely control channel
morphology; 3) determine the effects of recent flows on backwater habitats
and the main channel; 4) model flow and sediment transport through the
study area in order to determine the flows which maintain or enhance the
multi-thread nature of the reach, which is an indicator of habitat.
A GIS analysis using aerial photographs showed that the areas of
instream water, islands, and side channels/backwaters have decreased by
12-29 percent when comparing photographs from 1937 to 1993, and 1954 to
1968. An analysis of flow records showed that water development has
caused a significant decrease of 29 percent in peak flows in the upstream
end of the study area, and 38 percent in the lower end of the study area.
Cross-sections were surveyed across backwater habitats and the
main channel to measure the effects of the flows of 1993, 1994, and 1995.
Results indicate that channel change and habitat loss are relatively slow
processes which take several years to show significant changes_ Although
changes were small, high flows were clearly important for removing fine
sediments from backwater habitats.