Water-Supply Paper 2502Summary of Significant Floods in the United States, Puerto Rico, and the Virgin Islands, 1970 Through 1989Summary of Significant Floods, 1970 Through 1989, by State or TerritoryIn addition to the specific flood data, this section provides a description of the hydroclimatology and a summary of significant floods for each State or territory in the United States. The summary of significant floods includes those with loss of life or excessive damage during the period 1970 through 1989. The floods that were in the top 5 percent of each streamflow-gaging station's record during this period are tabulated, and an estimated recurrence interval is provided along with other pertinent data. A map of each State or territory is supplied to locate the streamflow-gaging stations. FloridaHydroclimatologyLocated in the southeastern United States, Florida is a peninsula bordered on three sides by ocean. Florida receives tropical moisture throughout the majority of its area during most of the year. Polar continental air occasionally enters northern Florida during the winter. The summer months typically receive the most rainfall as a result of convective showers. Hurricanes are a typical threat in the summer and fall months in Florida. Florida also has the highest number of thunderstorms per year in the Nation. Florida receives a statewide mean annual precipitation of 53 in. The majority of the annual precipitation falls during the May through September period. Stalled frontal systems in the winter months can cause excessive rainfall and flooding (Paulson and others, 1991). On the basis of regionalization procedures that relate flood characteristics to watershed and climatic characteristics, the magnitude of maximum discharges in Florida is dependent on total drainage area of the basin, channel slope, and the percentage of the drainage area covered by lakes and ponds. For the urbanized areas, additional information such as percentage of drainage area that is impervious and area controlled by detention structures improves estimates of maximum discharges (Jennings and others, 1994). Significant FloodsSignificant flooding occurred in Florida in September 1988. Ten percent of the streamflow-gaging stations in the State recorded significant discharges during this time. In the summer of 1975, nearly 20 in. of rain fell during a 4-day period in the eastern part of the Florida Panhandle causing severe flooding. The Choctawhatchee and Escambia River Basins were most affected by this flood. In April 1973, intense rainfall during a period of 6 days caused flooding in the Suwannee and St. Marys River Basins. The location of streamflow-gaging stations in Florida that had significant floods for 1970-89 is shown in figure 31a and 31b by station number. The specific data for each significant flood are listed in table 10. A significant flood is one that ranks in the top 5 percent of all annual maximum discharges for that station's period of record. References
Top of Page || Contents || Significant Floods, by Year || Significant Floods, by State or Territory || Figures || Tables || Glossary || Conversion Factors
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