FLOOD08149 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I The photograph of the July, 1965, flood on Clear Creek was provided by the Denver Post newspaper of Denver, Colorado. This report provides supplemental information for the Flood In- surance Study for Adams County (Reference 2), prepared for the Federal Insurance Administration, and for the Floodplain Informa- tion Report for Clear Creek (Reference 3). reported lost due to flood related causes in the Clear Creek basin. The following descriptions of the floods of August 1888, June 1956, and July 1965 are typical of the information currently available (Reference 3). - STUDY AREA DESCRIPTION - Flood of August 1888: This flood resulted from cloudbursts on the eastern slope of the front range of the Rocky Mountains. A discharge of 8,700 cubic feet per second was reported at the mouth of Clear Creek canyon. This is the largest measured discharge in the history of this gaging station which is located 1.5 miles upstream from Golden. The study area includes the reach of Clear Creek from its confluence with the South Platte River through the City of Golden. Within this reach, Clear Creek passes through unincorporated areas of Adams and Jefferson Counties and the Cities of Denver, Arvada, Wheat Ridge and Golden. Clear Creek, a left bank tributary to the South Platte River, has its source in the Rocky Mountains west of Denver. Flowing in a generally easterly direction from the Continental Divide, Clear Creek enters the high plains at Golden. The drainage area at the Golden gage near the bluff line is 400 square miles. From Golden, Clear Creek flows in a northeasterly direction to its confluence with the South Platte River near Derby. The Derby gage, which is located 0.6 miles upstream from the mouth of Clear Creek, has a drainage area of 575 square miles. Elevations in the basin range from 5,100 feet above mean sea level to over 14,000 feet above mean sea level (Reference 4). The location of the Clear Creek basin is shown on the Vicinity Map (Figure 1). The Clear Creek floodplain through Adams County and Jeffer- son County is largely comprised of undeveloped land and gravel mining operations. Residential areas in the vicinity of 44th Avenue in lfheat Ridge and in reaches through Golden would be inun- dated by a lOO-year frequency flood. The Coors complex east of Golden would also be inundated by this flood event. Flood of June 1956: Unusually heavy snowmelt runoff resulted in the failure of the Georgetown Dam located about one mile downstream from Georgetown. The peak discharge passing the gage above Golden was 5,250 cubic feet per second. By the time the crest reached the gaging station near the mouth of Clear Creek, it was reduced to 2,880 cubic feet per second. Flood of July 23-26, 1965: On July 23 and 24, during severe storms over the headwaters of Clear Creek and Tucker Gulch, 4.5 inches of rain was reported to have fallen in Tucker Gulch in an hour which caused flash flooding in Golden. Flooding, however, extended only a short distance downstream. In Golden, flood waters from Tucker Gulch spread over about 17 blocks and caused an estimated $112,000 damage to 69 resi- dences, three commercial enterprises, three railroad bridges, four street bridges and utility lines. At Georgetown, debris blocked the channel and diverted the waters down a street, thereby causing extensive waShing of the surface and the flooding of several basements. A scene typical of destruc- tion caused by flash floods in the Clear Creek basin is shown in Figure 2. - FLOOD HISTORY - Historically, flooding in the Clear Creek basin has been relatively infrequent. Since 1864, twelve floods have been reported on Clear Creek and its tributaries. No lives have been -2-