From the Purpose and Scope: "The purpose of this report is to describe the methods and results of a study to (1) update flood regions for all areas in Alabama; (2) update the AEP [annual exceedance probability] flows for rural streams at gaged locations; (3) update RREs [regional regression equations] for use at rural ungaged locations in Alabama; and (4) update the AEP flows for streamgages on large, regulated streams. All data used in support of the analysis and presented in this report, including geographic information system (GIS) data for the four flood regions in Alabama, are available from Anderson (2020). Urban stream flood frequency equations were not updated as part of this study and the results from Hedgecock and Lee (2010) are provided in table 1 for convenience. This report updates the flood-frequency analysis published by Hedgecock and Feaster (2007)."
Scientific Investigations Report 2020-5032
U.S. Geological Survey: https://usgs.gov/