Estimating and Mapping the Direct Flood Fatality Rate for Flooding in Greater New Orleans Due To Hurricane Katrina

Abstract

AbstractThe unprecedented tragedy of Hurricane Katrina produced unprecedented data for studying the impacts of natural disasters. The current paper looks at one public health outcome of this event: direct flood deaths in Orleans and St. Bernard parishes of Louisiana. In particular, the risk of death for the flood‐exposed population is estimated, mapped, and discussed. Of the nearly 1,500 deaths that Louisiana officially counts as Katrina deaths, approximately 600 are determined to be associated with exposure to floodwaters. Additionally, it is estimated that approximately 63,000 persons were exposed to floodwaters. The ratio of flood deaths to flood‐exposed population, termed the flood fatality rate, provides an empirical measure of flood risk. Georeferenced datasets on both the flood deaths and the flood‐exposed population are developed, and then used to estimate and map the flood fatality rate. For the overall event, the flood fatality rate is estimated to be 7 11 deaths per 1,000 persons exposed, which is consistent with other coastal flood disasters. At the blockgroup level, the highest values of the flood fatality rate are observed in the Lower Ninth Ward, while comparatively lower values are observed in New Orleans East. A preliminary univariate regression model with water depth as the independent variable is presented, and applied to Hurricane Gustav, which impacted the region in August 2008.