Comparative Analysis Of Flood Frequency Based On Radar-based Precipitation Data And Precipitation Trends

Abstract

This study utilizes radar-based precipitation data from the National Weather Service West Gulf River Forecast Center to extract the depth-area-duration relationships via the U.S. Army Corps of Engineers' software HEC-MetVue. Extreme storms from 1997-2013 were analyzed to determine the characteristics for synthetic design storms. Design storms of 10, 25, 50 and 100 year return periods were developed and simulated using the U.S. Army Corps of Engineers' hydrologic modeling tool, HEC-HMS. Finally, flood frequency analysis using the existing method was carried out for comparison and hydrologic impact assessment. The depth-area-duration curves produced were converted to areal-reduction factors for comparison with Technical Paper No. 40 and No. 49 by the U.S. Weather Bureau. The updated areal-reduction factors were found to be substantially lower in this study than the areal-reduction factors presented in the Technical Papers. This work also examines the factors contributing to the lower areal-reduction factors.