Estimation and Internet-Based Dissemination of Extreme Rainfall Information

Abstract

Information on extreme rainfall is employed extensively in design and analysis of storm-water conveyance systems and for other types of engineered hydraulic structures. Information needed for preparation of intensity-duration-frequency (IDF) curves or design storm hyetographs can be found in publications of the National Weather Service, including Technical Paper 40, HYDRO-35, and the National Oceanic and Atmospheric Administration’s Atlas 2. Rainfall data collected since the dates of these publications, and developments of improved statistical methods, have motivated several states and regions in the United States to initiate update studies. One of the new studies, for the state of Alabama, is reported. Results of the Alabama study are disseminated via an Internetbased graphical user interface, which permits users to interactively point and click on a geographical location of interest and have IDF curves or storm hyetographs returned on demand. User reactions to an Internetbased rainfall atlas have been promising and have led to additional work for the National Weather Service.