Envelope Curves for Extreme Flood Events

Maximum flood experience in a region can be depicted by a graph on which maximum known floods are plotted against drainage area. A smooth curve enveloping the plotted points provides the most concise description. such curves have been developed for 17 regions in the conterminous United States and are described by equations. The curves are not associated with specific probabilities or frequencies, but, within the region to which they apply, they give evidence as to the magnitude of flow that was occurred. Given similar basin characteristics, a peak lying close to the envelope curve might occur at other basins in the same region.