<br />26 FLOODS OF SEPT. 1970 IN ARIZ.. UTAH. COLO.. AND N. MEX.
<br />
<br />to spill over the highway; the engine of the lead car stalled, causing all to
<br />stop, and a wall of water poured across the road from the narrow upstream
<br />channel. All passengers in the stranded cars were able to reach high ground,
<br />except for an elderly couple who were swept away by the onrushing water.
<br />During the flood of 1970, the peak discharges at the three gaging stations
<br />on East Fork and West Fork of Sycamore Creek (fig. 7, No. 116-118) were
<br />from 4 to 6 times larger than the previous maximums for 10 years of record.
<br />Downstream from the confluence of the East and West Forks, the peak
<br />discharge at the gaging station on Sycamore Creek near Sunflower (fig. 7,
<br />No. 119) was 16,100 ft'ls (456 m'/s), which is twice the previous maximum
<br />for 10 years of record. At the gaging station 17 mi (27 km) downstream near
<br />Fort McDowell (fig. 7, No: 122), the peak was 24,200 f(3/s (685 m'/s), which
<br />is 1!.4 times the previous maximum for 12 years or record.
<br />
<br />CENTRAL ARIZONA
<br />
<br />27
<br />
<br />EAST VERDE RIVER BASIN
<br />
<br />The East Verde River drains westward from the Mogollon Rim. Beaver
<br />Valley, a community of summer homes on the river about 8 mi (13 km) north
<br />of Payson, suffered extensive damage from washouts and from the
<br />deposition of sediment and debris. Access to the community was cut off
<br />when the bridge over the East Verde River was washed out. The community
<br />swimming pool was filled with sediment, and a miniature railroad used to
<br />haul prospective buyers around a housing development was partly
<br />destroyed. Roads and recreational facilities in the national forest
<br />campgrounds along Mail and North Sycamore Creeks-tributaries of the
<br />East Verde River-were severely damaged.
<br />
<br />filled a caliche-lined irrigation ditch built by Indians nearly a thousand years
<br />ago; the ditch is rarely flooded. Measurements made by personnel of the
<br />National Park Service show that the ground-water discharge from
<br />Montezuma Well increased after the floods of September 1970-from
<br />about 1 Wls (28 Lis) in the summer to 1.2 ft'/s (34 Lis) immediately
<br />following the flood and to about 1.9 ft'/s (54 Lis) in November and
<br />December 1970.
<br />Dry Beaver Creek overflowed its bordering terraces and flooded an area
<br />of farmland one-fourth mi (0.4 km) wide upstream from McGuireville. The
<br />flood caused little damage at McGuireville, where the channel is wider than
<br />it is in the upstream reach, and the terraces were not inundated. At
<br />Montezuma Castle below the confluence of Wet Beaver and Dry Beaver
<br />Creeks, the flood crest was about 5 ft(1.5 m) higherthan that ofanyJ"Iood in
<br />the last 40 years (H. G. Egbert, Superintendent, Montezuma Castle National
<br />Monument, oral commun., 1970). As described by J. C. Knapp (National
<br />Park Service, oral commun., 1970), a sharp rise of8-9 ft (2.4-2.7 m) formed
<br />the crest of the flood and occurred in less than 10 minutes; the flood receded
<br />immediately after the rise. Residents reported that a logjam in Beaver Creek
<br />downstream near Camp Verde caused a temporary channel blockage, which
<br />forced the creek to overtop its banks and flood a narrow strip of the
<br />adjoining 20-ft-high (6.I-m-high) terrace.
<br />The flows from Oak and Beaver Creeks and from the East Verde River
<br />entered the Verde River and produced a peak discharge of 61 ,900 ft'l s (1,750
<br />m'/s) at the gaging station 9 mi (14 km) upstream from Horseshoe Dam (fig.
<br />7, No. 114). Although the discharge was the largest at the gaging station since
<br />1951, all the water was stored in Horseshoe and Bartlett Reservoirs.
<br />
<br />OAK CREEK AND BEAVER CREEK BASINS
<br />
<br />Large amounts of rain fell in the headwaters of the Oak Creek and Beaver
<br />Creek basins, and flood damage to roads, bridges, and culverts was
<br />widespread throughout the basins. Rockslides, mudslides, and pavement
<br />washouts stranded motorists and campers in Oak Creek Canyon near
<br />Sedona, and several housetrailers were severely damaged. The crest of the
<br />flood at the gaging station near Cornville (fig. 7, No. 96) was almost as high
<br />as that of the flood of March 1938, which was the highest reported since at
<br />least 1885.
<br />The Rocky Mountain Forest and Range Experiment Station of the U.S.
<br />Forest Service at Flagstaff operates 20 streamflow-gaging stations on small
<br />watersheds.in Beaver Creek basin. Several of these stations were badly
<br />damaged by the flood because the magnitude of the flow far exceeded that
<br />for which the stations were designed. The floods washed out control sections
<br />and gage shelters and deposited large amounts of gravel in the gage pools.
<br />The peak in Wet Beaver Creek above Red Tank Draw was not unusual;
<br />where Red Tank Draw joins Wet Beaver Creek at Montezuma Well,
<br />however, the flood caused a small amount of damage to trails and partly
<br />
<br />AGUA FRIA RIVER BASIN
<br />
<br />The storm of September 3-6 in the Black Hills and Bradshaw and New
<br />River Mountains caused flooding in the Agua Fria River and its main
<br />tributary-Black Canyon Creek-above Lake Pleasant. The peak
<br />discharge of 19,800 ft'ls (561 m'/s) in the Agua Fria River near Mayer (fig.
<br />7, No. 127)was mainly from Ash Creek and Yarber Wash, which drain south
<br />from the Black Hills, and from Big Bug Creek, which drains from the east
<br />slope of the Bradshaw Mountains. The flood crest at the Agua Fria River
<br />near Mayer gaging station was the highest since the beginning of record in
<br />1940 and was about 3 ft (0.9 m) higher than the previous maximum;
<br />however, at Rock Springs just above the confluence with Black Canyon
<br />Creek, residents reported that floods of equal magnitude had occurred
<br />several times in recent years.
<br />The Agua Fria River leaves a narrow canyon and enters a broad alluvial
<br />valley near Rock Springs. Upstream from Interstate Highway 17, aggrading
<br />and shifting bars in the braided river channel spread the flood onto low
<br />terraces and threatened buildings and homes (table 3). Downstream from
<br />Interstate Highway 17, a dense thicket of young willow trees formed a
<br />
|