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<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 />