7632 ‎(2)‎

• UCREFRP Catalog Number: 7632
• Author: Pucherelli, M. J., J. N. Halls and R. C. Clark.
• Title: Green River Channel Mapping Study, 1987.
• USFW Year: 1987.
• USFW - Doc Type: \
• Copyright Material: NO

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3.0 RESULTS AND DISCUSSION

Table 1 presents the channel area (acres), length (feet). and average
channel width (feet) of each Green River segment studied in 1952 and
1963. The 1952 and 1963 dates are considered predam conditions, and
it is evident that little or no significant change in channel width
or area occurred between these dates. Of the 25.5 miles of alluvial
riverbed, there was a change in channel area from 2.104 acres in 1952
to 2,135 acres in 1963, a net increase of 1.5 percent. The increase
of 31 acres over 25.5 miles equates to 1.2 acres per river-mile. The
3.7 miles of nonalluvial sites changed from 339 acres in 1952 to
342 acres in 1963, a net increase of 1.1 percent. The increase of
3 acres in 3.7 miles equates to 1.0 acres per river-mile. The total
channel area of the river studied increased from about 2.442 acres
to 2,478 acres, an increase of only 1.4 percent. The net increase
of 35 acres in 29.3 miles equates to 1.2 acres per river-mile. The
net change in average channel width from 1952 to 1963 ranged from a
loss of about 11 feet for river-miles 123 to 117 (alluvial) to a gain
of about 16 feet for river-miles 190 to 170 (alluvial). The total
width of the river increased from 688 feet in 1952 to 698 feet in 1963,
a net increase of only 10 feet or 1.4 percent.

Table 2 presents the channel area (acres) length (feet) and average
width (feet) for river-miles 190 to 131 and 128.3 to 117 in 1963. 1974,
1978, and 1986. From 1963 to 1974. there was a net loss in river channel
width and area. The channel area of all alluvial sites changed from
3,533 acres in 1963 to 3,343 acres in 1974, a net decrease of 5.4 percent.
A net loss of 190 acres in 41.8 river-miles equates to 4.5 acres per
river-mile. The nonalluvial channel area changed from 2.424 acres
in 1963 to 2.257 acres in 1974, a net decrease of 6.9 percent. A net
loss of 167 acres in 27.4 miles equates to 6.1 acres per river-mile.
The net change in average channel width from 1963 to 1974 ranged from
a loss of 21 feet for river-miles 190 to 170 (alluvial) to a loss of
85 feet for river-miles 142 to 131 (alluvial). In alluvial areas,
the average channel width changed from 697 feet in 1963 to 660 feet
in 1974. a net decrease of 5.4 percent. In the nonalluvial area. the
average channel width changed from 729 feet in 1963 to 679 feet in
1974, a net decrease of 6.9 percent. The average width of the total
river studied changed from 710 feet in 1963 to 667 feet in 1974, a
net decrease of 43 feet or 6.0 percent.

Very little change in channel width and area occurred from 1974 to
1978. Channel area increased from about 5,600 acres to 5,612 acres,
a net increase of only 0.2 percent. Similarly, channel width increased
by only about 1 foot during this time period. Alluvial stretches of
the river decreased slightly in area and channel width. Channel area
decreased from 3.343 acres to 3.336 acres (- 0.2 percent). while channel
width decreased from 660 to 659 feet. The nonalluvial stretch increased
from about 2.257 to 2,275 acres and from 679 to 684 feet channel width
(+0 .8 percent).