Probabilistic Flood Risk Assessment Under Climate Change Scenarios in the Humber River Watershed

Flood frequency is expected to increase due to climate change. This research uses the CAPRA method to perform flood risk assessment in the Humber River watershed. The economic and social damages are quantified under current and future climate conditions. First current and future stochastic precipitation maps are generated. The future precipitations consider the climate scenarios from the IPCC AR5 for three time periods. Next the corresponding floodplain maps are generated using hydrological (HEC-HMS) and hydraulic models (HEC-RAS). Finally, flood risk is calculated by integrating the floodplain maps with the vulnerability of exposed elements. Results reveal an increase in the flood risk for most of the climate scenarios by the end of the 21st century, where the highest and lowest flood risk are for the RCP 8.5 and RCP 4.5 scenarios, respectively. The long-term period shows the highest increases. Further sensitivity and uncertainty analysis is recommended for future research.