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<br />Flood of 2-6 June 1921, This storm produced general rains over the South Platte basin with the greatest
<br />amounts along the foothills, It covered an area of approximately 520 square miles and lasted 5 days, The
<br />maximum recorded rainfall was 5,29 inches and the greatest recorded rainfall intensity was 4,3 inches in six
<br />hours at Longmont This flood was produced by a combination of rainfall and snowmelt Although this storm
<br />caused overbank flooding, neither discharges nor damagE!S were recorded,
<br />
<br />Flood of 3 Seotember 1938. During this storm, sllOwers were general over the Left-Hand Creek basin
<br />accompanied by isolated cloudbursts along the foothills and the lower elevations, A maximum peak discharge
<br />of 812 cubic feet per second was recorded at the U,S, Highway 287 gaging station near Longmont This gaging
<br />station was not in operation during the 1949 and 1951 floods,
<br />
<br />Flood of 4 June 1949, On 4 June 1949, the Left Hand Creek had overbank flooding as a result of heavy and
<br />prolonged rainfall during Late May and early June and the runoff from an unusually heavy snow blanket The
<br />prolonged high flow on Left Hand Creek caused minor damages to irrigation headworks, bridges, and
<br />farmlands, The gaging station near Boulder recorded a peak discharge of 1,140 cfs during the flood period,
<br />
<br />Flood of 3 Auaust 1951, During the afternoon and night of 3 August, a heavy rain storm occurred over the
<br />frontal range and foothills east of the Continental Divide from the vicinity of Boulder to near Fort Collins,
<br />Colorado, a distance of approximately 50 miles, One of the storm centers was in the Left-Hand Creek near
<br />the town of Niwot At this storm center, total precipitation was unofficially reported to have been over inches.
<br />The runoff from this storm caused flooding on St Vrain Creek and on it's tributaries, Dry Creek and Left,Hand
<br />Creek, Overbank flows occurred along most of the length of Left,Hand Creek, Bridges, roads, crops, and
<br />irrigation structures were damaged.
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<br />4,1.10 DRY CREEK
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<br />Flood Historv, Little information is available relative to historic flooding on Dry Creek probably because of
<br />its rural nature which has resulted in little flood damage durin!) flood events, Information is available, however,
<br />on adjacent streams which indicate that floodwater may have been experienced on Dry Creek, ThE~ following
<br />are accounts of some of the heavy rainfall events which Ilave occurred in the Dry Creek area,
<br />
<br />Flood of Mav-June 1894, Heavy rains fell on 19 May - 2 ,June over the mountains and plains E!xtending from
<br />the Colorado-Wyoming border southward into the Republican and Arkansas River basins, 'Rainfall amounts
<br />over the high plains gradually decreased from west to east varying from 5 inches at Boulder to approximately
<br />2.5 inches at the mouth of Boulder Creek,
<br />
<br />Flood of June 1921, Heavy general rainfall occurred frorn :Z June - 6 June over the South 1"latte River basin
<br />with the greatest amounts along the foothills of the Rocky Mountains, Rainfall covered an area of
<br />approximately 520 square miles. The maximum recorded rainfall was 5.29 inches and the weatest recorded
<br />rainfall intensity was 4,3 inches in 6 hours at Longmont Rainfall totaled 3,36 inches at Boulder,
<br />
<br />Flood of August-September 1938, Heavy rainfall occurred from 31 August to 4 September over all of
<br />eastern Colorado, Boulder reported 3,36 inches of precipitation from 31 August to 4 September with 2,32
<br />inches falling during 2 September,
<br />
<br />Flood of Auaust 1951, On the afternoon and evening of 3 August, very heavy rainfall occurred along 50
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<br />Colorado Flood
<br />Hydrology Manual
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<br />4,12
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