9670

• UCREFRP Catalog Number: 9670
• Author: Pitlick, J.
• Title: Channel Monitoring To Evaluate Geomorphic Changes On The Main Stem Of The Colorado River.
• USFW Year: n.d.
• USFW - Doc Type: Boulder, CO.
• Copyright Material: NO

Backwater cross sections were monitored at three other sites, one located several hundred
meters downstream of the lower end of the RM 176 study reach, and two others located in the
18-mile reach, which were first surveyed in 1993 as part of an earlier study (Pitlick et al., 1999).
The backwater at RM 175.5 is short and moderately sinuous, whereas the other backwaters are
relatively long and straight. A substantial amount of sediment was deposited in the backwater at
RM 175.5 in the first two years of monitoring (Fig. 13a); subsequently, in 2002, the mouth of the
RM 175.5 backwater was dammed by beavers, eliminating access to and from the main channel.
Sedimentation in the other two backwaters was minor in comparison. The backwater at RM 162
aggraded by 0.2 to 0.5 m between 1995 and 2001 (Fig. 13b), whereas the backwater near RM
160 changed little, except for deposition of a small berm along the right bank (Fig. 13c)

100.0
RM 175.5 Backwater
99.5 XSECT 4
99.0
E
98.5
°
0 orJ
TO 98.0
a)
w
t 3/24/98
97.5
f 6/24/98
97.0 -? 8/14/99
0 3/29/01

96.5
0 10 20 30 40 50 60 7 0
Distance (m)
Figure 13. Backwater cross sections in other locations within the 15- and 18-mile
reaches.
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