Scientific Investigations Report 2010–5012
Methods of estimating flood magnitudes for exceedance probabilities of 50, 20, 10, 4, 2, 1, 0.5, and 0.2 percent have been developed for urban streams in Alabama that are not significantly affected by dams, flood detention structures, hurricane storm surge, or substantial tidal fluctuations. Regression relations were developed using generalized least-squares regression techniques to estimate flood magnitude and frequency on ungaged streams as a function of the basin drainage area and percentage of basin developed. These methods are based on flood-frequency characteristics for 20 streamgaging stations in Alabama and 3 streamgaging stations in adjacent States having 10 or more years of record through September 2007.
First posted June 7, 2010
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Hedgecock, T.S., and Lee, K.G., 2010, Magnitude and frequency of floods for urban streams in Alabama, 2007: U.S. Geological Survey Scientific Investigations Report 2010–5012, 17 p.
Purpose and Scope
Description of the Study Area
Flood Data Used in the Analysis
Flood Magnitude and Frequency at Gaging Stations
Urban Flood-Frequency Analysis
Accuracy and Limitations of Flood-Frequency Estimates
Use of Flood-Frequency Relations
Comparison of Results with Previous Alabama Study Results