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<br />4. Current Problem\Issue Identification <br /> <br />A. Flood Hazard Inventory <br /> <br />The first step in the flood hazard inventory process is to define the flood hazard. To <br />undertake this process, one should review the flood history of Floodville. One important area <br />of focus of the Flood Mitigation Assistance Program will be repetitive loss areas. The local pre- <br />disaster flood hazard mitigation plan should focus on such areas because of the often <br />disproportionate amount of flood damage which occurs here. <br /> <br />1. History of Flooding <br /> <br />Flooding from streams in Floodville usually occurs during June through August, with the <br />principal cause of flood flows being thunderstorms. The community is known to have a long <br />history of flooding, the earliest occurring in 1888 (Reference 4). The flood of June 30 - July I, <br />1917 is considered the most severe in the Floodville area, with an estimated peak discharge of <br />7,120 cfs on High Ball Creek. The largest flood on Risky Creek occurred in 1921, with an <br />estimated peak flow of 1,235 cfs. The largest discharge recorded on High Ball Creek was on <br />July 21, 1957, with a peak of 6,800 cubic feet per second (cfs). General rains lasting up to five <br />days in mid-June 1965 caused significant flooding with discharges on High Ball and Risky Creeks <br />of 5,775 cfs and 975 cfs, respectively. In 1973, large snow depths in the South Platte River basin <br />resulted in unusually high snowmelt flows. In 1992, a long lasting, intense thunderstorm caused <br />moderate flooding on Risky and High Ball Creeks with discharges of 720 cfs and 3,440 cfs, <br />respectively. <br /> <br />A U.S. Army Corps of Engineers report (Reference 3) describes the 1957 flood as <br />follows: <br /> <br />Floods on High Ball Creek on July 21, 1957 had an instantaneous peak discharge of <br />6,800 cft at the High Crest gage, This flood was the maximum of 52 years of record, and <br />its magnitude has an estimated frequency of occurrence of once in approximately 70 <br />years, <br /> <br />The creek in the problem area is characterized by low banks, braided channels and a <br />considerable amount of gravel, cobbles and snags deposited on gravel bars. <br /> <br />6 <br />