FLOOD00867

• County: Statewide
• Title: Determination of Channel Change for Selected Streams, Maricopa County, Arizona
• Date: 1/1/2002
• Prepared For: Maricopa County Arizona
• Prepared By: USGS
• Floodplain - Doc Type: Educational/Technical/Reference Information

10,000 500
0
z
0
u
UJ l-
f/) UJ
a: 400 UJ
UJ I.L
"- 7,500 UJ
I- a:
UJ '"
UJ ~
I.L a
u ~ Cross-Sectional Area f/)
<D 300 ""
~ -i
u
. UJ
"" 5.000 a:
ui . '"
-'
'" '"
a: Annual Peak 200 z
'" 0
I Discharge ;:::
U U
f/) UJ
is f/)
'" 2,500 ch
'" f/)
UJ No 100 0
"- record No record a:
-' u
'" ,-J-., ^
~
z
z
'"
0 0
1963 1968 1973 1978 1983 1988 1993 1997
WATER YEAR

Figure 25. Annual peak discharge and cross-sectional area. Tiger Wash near Aguila, Arizona, 1963-97.

and deepened as compared to the previous meas-
urement. Sediment was scoured from the channel
bottom and deposited on the left bank (fig. 26).

A second large flood occurred in 1995, and the
discharge was measured at 78,200 ft3/s on Feb-
ruary 15 (fig. 26). The cross section during this
flow shows several feet of scour on the channel
bed. The discharge measurement on April 28,
1995, shows that the channel filled to a level
comparable with the level before the 1993 flows.

09514200 Waterman Wash near Buckeye,
Arizona

Waterman Wash near Buckeye (fig. I) is an
ephemeral sand channel that flows through
Rainbow Valley, which is filled with alluvial sedi-
ments that originate from the Estrella and
Maricopa Mountains to the northeast and south-
west, respectively. Waterman Wash has a drainage
area of 420 mi2 and an elevation of about 1,000 ft

at the gaging station. Bed material at the gaging
station is mainly sand with some gravel. The chan-
ne] is incised into the valley alluvium.

Surveyed cross sections.-The cross sec-
tion was measured near the gaging station. Re-
surveys were reconstructed from five indirect
measurements of discharge and one cross-section
survey (fig. 28). The first measurement was made
in 1964. Subsequent cross sections were surveyed
in ]966, 1971, 1982, 1996, and 1997. Nearly all
channel change was vertical (fig. 28). Vertical
change in the streambed elevations has been as
much as 2 ft between surveys and as much as
3.5 ft overall between 1966 and] 982. The channel
filled almost 60 percent of the cross-sectional area
relative to the reference elevation between 1964
and 1982. A survey following the flood of
August 8, ] 997, showed a l3-percent increase in
cross-sectional area. The flow of August 8, 1997,
of 9,400 ft3/s was the peak discharge ofrecord at
this site (fig. 29).

36 Determination of Channel Change for Selected Streams, Maricopa County, Arizona