7104

• UCREFRP Catalog Number: 7104
• Author: Green, B. and M. Butler.
• Title: Analysis of Channel Maintenance and Flushing Flows in the Colorado River at the Palisade Habitat Site ‎(Appendix B)‎.
• USFW Year: 1987.
• USFW - Doc Type: \
• Copyright Material: NO

~

An analysis of discharges required to flush fine sediment from the
Palisades IFIM site was performed using the method described by
Milhous. Graphs of the Beta movement parameter versus discharge at
cross sections 1 and 3 (Figure 1) were prepared for the dSO
material size of 72 rom as shown in the report by Simons (Figure 2).
Hydraulic radius is calculated using the conveyance area divided by
the top width, and the energy slope for each discharge is from the
Water Surface Profile (WSP) program of PHABSIM. Energy slope is
taken directly from WSP for cross section 1 and computed for cross
section 3 (Figure 3). The energy slope at cross section 3 is
computed by dividing the change in total energy from section 4 to 2
by the distance between the cross sections. The calculated Beta
movement parameters for cross sections 1 and 3 are in Tables land
2, and Table 3 shows the computed energy slopes for cross section
3 .

The maximum discharge measurement used to define the stage-
discharge relati.onship is 10,060 cfs. A number of WSP runs were
made in order to calculate the Beta movement parameter. However,
the calibrat~_on becomes uncertain for flows greater than 12,000
cfs. A discharge measurement greater than 12,000 cfs is needed to
make the WSP calibration more reliable for flows greater than
12,000 cfs.

Examination of the graph at cross section 1 for the dSO size
(Figure 1) shows the Beta movement parameter is above 0.021 for the
1,500 to 8,000 cfs discharge range. The parameter is near 0.020
for discharges between 8,000 and 12,090 cfs and then increases to
0.021 above 13,000 cfs. Cross section 1 thus appears to have fines
flushed from the substrate over a'wide range of flows.

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