FLOOD04656 - Laserfiche WebLink

Home Browse Search

E88 S~Y OF FLOODS E89 FLOODS OF 1965 IN THE UNITED STATES 119015" 110/00' TABLE SO.-Flood stages and discharges, July 24; in the vicinity of Clinchmore, Tenn. No. Stream and place of determination D""-' area (sqmi) Maximum discharge- Cfs Cfs per "lm! 45 45' o&ho M"port l=:J 1 Ligias Fork above Graves Gap Branch.__ 8.99 2 GrsvesGapBra.nchnearmouth.h__U____ 3.16 3 Ligias Fork near mouthun_....umnu 20.4 4 StonyForkaboveClinehmore.._.___nu_ 6.34 5 StonyForkbelowCllnchmore-.....______ 7.67 ~~~. 9,750. 12,300 13,500 382 1."" 478 1,940 1,760 EXPLANATION . Flood-determination point Cumberland River basin Tennessee River basin 6 CoalCreek:aboveBriceville....___._n___. 5.36 2,000 373 7 SIatestoneHollowBranchnearmouth____ 3.66 500 137 8 Coal Creek at Briceville..__mnnnn___ 10.3 2,500 243 completely. destroy.ed. Tremendous amounts of rock, uprooted trees, and other debris were washed down the sides of the mountains and deposited ill the streams and narrow valleys, This flood is described in more detail by the Tennessee Valley Authority. (1965), FLOOD OF JULY 26 NEAR ECHO, OREG. ~y D. D. HARRIS A severe cloudburst on July 26 caused flash floods in a small area in western Umatilla County, Oreg., southeast of the town of Echo (fig. 41). The storm was centered over an area south oUhe Umatilla River near Nolin and extended into the upper Butter Creek basin. The result- ant llash flood demolished a house at the mouth of Speare Canyon and swept away its six occupants, One person was drowned, and the others were injured. Flooding in Lane Cany.on destroyed a Union Pacific Railroad bridge n~ar the canyon mouth. Heavy. erosion occurred. throughout the 'yloudburst area, Considerable amounts of hay and wheat were flattened, washed away., or buried under layers of silt, rock, and other debris, .Local residents stated that most of the rain fell in about half an h~ur and was accompanied by. much hail.. The storm was most severe in the upper parts of the watersheds which are uninhabited; therefore, no measurements of precipitation intensities were made in these areas. Extremely high peak discharges of the July 26 flood were measured by. indirect methods at two sites: 28,500 cfs (5,650 ofs per sq mi from 5.04 sq mi) near the mouth of Lane Canyon and 14,600 cfs (635 ofs per sq mi from 23,0 sq mi) near the mouth of Speare Canyon, The degree of gully. erosion indicated that the entire Lane Cany.on dramage 4" 30' , I o I 5 MILES I FIGURE 41.-':"Location of tlood--determination points, floods of July 26 near Echo, Oreg. basin had heavy. runoff, whereas that in only. a part of upper Speare Canyon drainage basin indicated heavy. runoff. High flows also oc- curred in Mud Spring and Alkali Cany.ons and in Butter Creek (fig_ 41), but they were not comparable in magnitude with those in Lane and Speare Canyons, . Recurrence intervals for the peak discharges in Speare and Lane Canyons were obviously. high, although definite frequencies cannot be computed. The flood area is covered by. a flood-frequency. report (Hulsing and Kallio, 1964), but the report is not applicable to drain- age areas less than 10 sq mi nor for recurrence intervals greater than 50 years. The extreme rarity. of two such peak discharges in this a-rea is illustrated by. fignre 42, which indicates the great ratio by. whioh the discharges exceed 50- y.ear floods.