Flood vulnerability curves and household flood damage mitigation measures: an econometric analysis of survey data

Natural disasters, such as flood events, are expected to increase in their frequency and severity, which results in higher flood risk without additional adaptation measures. The information gained from flood risk models is essential in flood risk management. However, vulnerability model components in the form of depth-damage curves are often a large driver of uncertainty and empirical vulnerability curves are rarely estimated due to a lack of damage data from flood events. This study uses a unique dataset with experienced damages and the implementation of flood damage mitigation (FDM) measures on the household level, collected after the flood event in the Netherlands in 2021. Two main findings emerge from an analysis of this dataset. First, depth-damage curves that control for several hazard, exposure and vulnerability indicators are estimated. These curves serve as an update to current input in flood risk models, where previous vulnerability estimates from the Netherlands are based from a flood event in the 1950s. Second, it is found that previous studies on the effectiveness of FDM measures are prone to a selection bias, as households that do and do not take FDM measures systematically differ in their risk profiles. By using an Instrumental Variable (IV)-estimation, this study overcomes this selection bias and finds significant reductions in flood damage to both buildings and household contents due to FDM measures.