Creating a Water Risk Index to Improve Community Resilience

Flood risk reduction is an existent discourse and agenda in policy and insurance. Existing approaches such as linking hydrological models to economic loss models may be highly inequitable between areas of different socio-economic vulnerability. To our knowledge no one has tried to adapt the more advanced known heat risk theory by first informing flood risk with the socio-economic vulnerability, and then investigating the sensitivity of risk reduction policies to that flood risk. Here we demonstrate two methods to combine water hazard data with a derived water vulnerability index to characterize water risk. We then compare the costs of two potential government policies: buyout of the home versus funding for foundation elevation. We use the case study area of Pittsburgh, PA, which faces severe precipitation and riverine flooding hazards. We find that while small differences in characterizing flood risk can result in large differences between flood risk maps, that the cost of the flood risk reduction policy is not sensitive to the method of representing the socio-economic vulnerability. This suggests that while validation of flood risk incorporating socio-economic data is needed, for some policies, policy makers can prioritize environmental justice with little to no additional cost.