Variability of Best-Estimate Flood Depth Return Periods in Coastal Louisiana

Abstract

We empirically examine the degree to which best-estimates of coastal Louisiana floodplains have changed over time and consider implications for risk management policies. We generate variation in estimated 100-year flood depths by truncating a historical data set of observed tropical cyclones to end in years ranging from 1980 to 2016, adopting three procedures for updating various inputs to an existing flood risk model using the truncated data set to identify which factors are most important in driving variation in risk estimates over time. Our findings indicate that the 100-year floodplain extent has substantially expanded in populated areas since 1980 due to these effects.