FLOOD05245

• County: Statewide
• Community: State of Colorado
• Stream Name: All
• Basin: Statewide
• Title: Floods of September, 1970 in Arizona, Utah, Colorado, and New Mexico
• Date: 1/1/1978
• Prepared For: State of Colorado
• Prepared By: USGS
• Floodplain - Doc Type: Flood Documentation Report

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FLOODS OF SEPT. 1970 IN ARIZ., UTAH, COLO., AND N. MEX.

CENTRAL ARIZONA

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FIGURE 1O.~Cabin damaged by the flood in Tonto Creek near Kohl Ranch.

parallel with the channel of Tonto Creek. High-water marks at the
confluence were 18 ft (5.5 m) above the bed ofTonto Creek and only 2ft (0.6
m) above the top of the bar. The gravel bar and the high-water marks
indicate that the peak discharge of Houston Creek was nearly coincident
with that of Tonto Creek.
Although the discharge of Rye Creek was comparable to that of Tonto
Creek, only minor flood damage occurred in the Rye Creek basin. The flood
near the mouth of Deer Creek, a tributary to Rye Creek, was reported by
T. P. Hughes (local resident, oral commun., 1970) as being the largest since
1932. In the broad valley of Tonto Creek near Punkin Center, most of the
terrace that borders the wide gravelly channel was inundated, and an area as
much as one-half mi (0.8 km) wide was flooded (pi. I).
The peak discharge of 18,400 [(' Is (521 m'l s) in Tonto Creek below Kohl
Ranch (fig. 7, No. 85), 11,900 ft'ls (337 m'/s) in Christopher Creek (fig. 7,
No. 86), and a large flow from Haigler Creek produced a peak discharge of
38,000 ft'ls (1,080 m'/s) in Tonto Creek near Gisela (fig. 7, No. 88). The
peak discharge of 44,400 ft'/s (1,260 m'/s) in Rye Creek near Gisela (fig. 7,
No. 89) entered Tonto Creek 2 hours before the peak moving downstream in
Tonto Creek. The peaks were of extremely short duration, which caused two
separate peaks 2~ hours apart 5 mi (8 km) downstream at the Tonto
Creek above Gun Creek, near Roosevelt gaging station (fig. 7, No. 91). The
higher of the two peaks-53,000 ft'ls (1,500 m'/s)-is the maximum
discharge recorded since the station was established in 1940. Downstream
from Tonto Creek above Gun Creek gaging station, records from two
abandoned staff gages indicate that the flood of 1970 may have been the
largest since the early 1900's.
Tonto Creek flows into Roosevelt Lake-the uppermost reservoir in the
Salt River Reservoir system. On September 4, storage in the reservoir system
was at a minimum for the year, and all the flow that entered Roosevelt Lake
from Tonto Creek on September 5 was stored in Roosevelt Lake and the
other three lakes that make up the Salt River reservoir system (fig. 7, No. 93).

are on a natural levee, which was inundated by about I ft (0.3 m) of water.
One person was drowned when wading from the levee through the deeper
water adjacent to the levee. Mr.. Eddie Potter (local resident, oral commun.,
1970) stated that the flow tossed boulders several feet into the air at the
embankment of State Highway 160. Boulders and cobbles were strewn on
the highway, and a large cottonwood tree was jammed through an
unoccupied cabin by the force of the water; the cabin was damaged so
severely that it was later torn down.

Tonto Creek is in a steep-walled canyon for several miles downstream
from Christopher Creek. No serious damage was reported or observed
during an aerial reconnaissance of Bear Flat, the only development in the
area. Tributaries to Tonto Creek downstream from the canyon carried
extremely high flows. Long reaches of bedrock were exposed along Haigler
Creek, as the flood cleared everything in its path including timber and soil
cover. The flood in Houston Creek filled a diversion ditch with sand and
gravel-the first such occurrence since the ditch was constructed a few
decades ago. A gravel bar 16 ft (4.9 m) high was deposited at the mouth of
Houston Creek. The downstream end of the bar forms an escarpment that is

SYCAMORE CREEK BASIN

During September 3-6, at least 7 inches (180 mm) ofrain fell in the upper
part of the Sycamore Creek basin, and as much as 10 inches (255 mm) was
recorded at one precipitation station. Long-time residents reported that the
flood of 1970 was the largest known in the area. Many stock tanks built in the
last few decades were breached by runoff. Three persons were killed as a
result of flooding in Sycamore Creek. An Arizona State Highway patrolman
on an emergency call was killed when his patrol car plunged into Sycamore
Creek at the washed-out bridge 5 mi (8 km) south of Sunflower, and two
persons were drowned a short distance upstream from Sunflower (pi. I).
According to L. T. Walker (local resident, oral commun., 1970), several
motorists proceeded on State Highway 87 near Sunflower as the flood began