7920

• UCREFRP Catalog Number: 7920
• Author: Van Steeter, M. M., J. Pitlick and B. Cress.
• Title: Aerial Photograph/GIS Analysis and Field Studies of the Grand Valley and Ruby-Horsethief Canyon of the Colorado River.
• USFW Year: 1995.
• USFW - Doc Type: \
• Copyright Material: NO

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37

Results
Palisade
Flows at the Palisade site show an increase in the reach averaged
velocity, depth, slope, and shear stress with increasing discharge (Table 5).
Figure 18 shows how the bed elevation, and water surface slope change at
different flows. At a flow of 54 cms the slope is relatively flat since there is a
riffle downstream of the surveyed cross-sections which backs up the flow. At
higher discharges this downstream control has a smaller affect and the slope
increases at all cross-sections, but especially over the crest of the riffle. Figure
18 also illustrates the relationship between shear stress and discharge. It
shows that initial motion ('t*=0.03) of Dso occurs near a discharge of 350 cms
(12,350 cfs) and significant transport associated with 't*=0.06 occurs at a
discharge near 725 cms (25,600 cfs). These flows are approximately the 1.26 and
4.3 year flood respectively.
Corn Lake
Flows at Corn Lake show a similar trend to Palisade with an increase in
reach averaged velocity, depth, slope, and shear stress with increasing
discharge (Table 6). Figure 19 shows that the water surface is relatively flat at
low flows, but the slope increases with discharge. It also shows that initial
motion of Dso occurs near a discharge of 250 cms (8,825 cfs), and significant
transport occurs at a discharge of approximately 525 cms (18,525 cfs). These
flows are approximately the 1.11 and 2.0 year flood respectively. These values
are less than those at Palisade primarily because the grain size is finer at Corn
Lake.