Social inequalities in flooding inside and outside of floodplains during Hurricane Harvey

Abstract

While previous research often finds flood impacts outside of conventional flood risk zones such as FEMA’s 100-year floodplain maps, we have less of a sense of the social and demographic composition of the areas outside of floodplains that experience these impacts, even though social inequalities in flood risk and impacts more broadly is well-documented in the United States. Using data on 100-year floodplains, flood impacts, socio-demographic characteristics, and residential parcels, this study focuses on race as a primary marker of socio-spatial inequality to examine flooding inside and outside of floodplains during Hurricane Harvey in Greater Houston. Descriptive findings show that a large majority of flooding occurred outside of 100-year floodplains. Regression models show that while there is limited evidence of racial inequalities in flood risk as conceptualized as location in 100-year floodplains, there are substantial racial inequalities in flood extent during Hurricane Harvey. Results further show that these overall racial inequalities in flood extent are primarily driven by impacts that occurred outside of 100-year floodplains. Conclusions center on how and why conventional delineations of flood risk can underestimate racial inequalities to natural hazards.