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<br />Flood of Mav 1973, Rainfall generally ranging to as much as 6 inches fell on the plains
<br />east of the Rocky Mountains beginning on 5 May, The Dry Creek basin received amounts
<br />ranging from 2 to 4 inches, Runoff from this general storm contributed to considerable
<br />flooding on the South Platte River.
<br />
<br />4.1.11 ST. VRAIN CREEK
<br />
<br />Flood Historv, Early records of floods are fragmented and lacking in detail. Flooding
<br />occurred on St. Vrain Creek in 1864, 1876, 1894, 1921, 1938, 1941, 1949, 1951, 1957,
<br />and 1969,
<br />
<br />Flood of June 1864. A storm in June 1864 resulted in a flood, the effec1s of which
<br />reportedly "were feR severely" in the St. Vrain valley.
<br />
<br />Flood of Mav 1876, The Golden, Colorado Tribune of May 31, 1876 described a flood
<br />during that month as covering farmlands from "bluff to bluff" at the junction of SI. Vrain and
<br />Left Hand Creeks, at Longmont.
<br />
<br />Flood of 31 Mav 1894, The flood of 31 May 1894 washed away 20 homes at Lyons,
<br />"A day or two before Memorial Day in 1894, a steady rain began to fall which soon
<br />reached flood proportions, and the entire lower part of the town was washecl away, No
<br />lives were lost, ,," This flood had an estimated peak discharge of 9,800 cubic feet per
<br />second (cfs) at Lyons, a flood of such rnagn~ude as to have less than a 1 "in-50 chance
<br />of occurrence in any year. South St. Vrain Creek contributed the greater pall of the flood,
<br />
<br />Flood 30-31 Julv 1919. In late July 1919, a series of severe thunderstorms caused
<br />flash flooding along St. Vrain Creek. From the Lyons Recorder dated 2 August 1919:
<br />"The heaviest and most destructive cloudburst. , ,in the memory of the oldest inhabitant
<br />visned Lyons on Wednesday (July 30) between 2:30 and 3:45 p,m, It took out all the
<br />bridges on the North 81, Vrain for about 5 miles up and 5 miles downstream. The
<br />Longmont and Lyons water mains up the canyon were torn out in many places. , , miles
<br />of road were torn out along the narrow canyon, The people living along the banks of the
<br />river were flooded out, and many abandoned their homes for higher ground and safety ,
<br />, , homes (in the lower part of town)", were in a roaring sea of water 2 and 3 feet deep:'
<br />Another crest on the fOllowing day again flooded houses in the lower areas of town and
<br />washed out 300 yards of railroad track east of Lyons, The peak discharge on ,lQ July was
<br />later computed to be 9,400 cfs, The right bank of North St. Vrain Creek was flooded to
<br />a width of 300 feet.
<br />
<br />Flood of 2-7 June 1921, Heavy rains combined wnh snowmeR runoff caused flooding
<br />in the Longmont area early in June of 19:21. A total of 5,87 inches of rain was recorded
<br />at Longmont from 2 to 7 June. The Boulder Camera of 7 June 1921 reported that SI.
<br />Vrain Creek at Longmont was "way out of ns banks" and "three-quarters of a mile wide,
<br />Water is up to the Farmer's Mill and the depot. All bridges in the cny are out or
<br />
<br />Colorado Flood
<br />Hydrology Manual
<br />
<br />4,15
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<br />~FT
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