Enhancing Coastal Flood Resiliency in Canada Through Hazard and Life Safety Assessments

Abstract

Home to the world’s longest coastline, Canada has experienced devastating economic and social from coastal flooding events. While there have been a variety of mitigation methods employed over the years to increase a community’s resistance to coastal hazards, it is unrealistic to think that there exists a solution to guarantee a community’s safety under all possible flood hazards. Instead, the community’s efforts to raise their resistance to flood hazards should be augmented with careful planning and management to increase a community’s resilience to flood hazards, allowing them to recover quickly after a natural disaster. The first step in elevating a community’s resilience is to better understand the expected hazards that it may experience. This thesis presents two unique case studies to better understand the flooding hazards present on the Canadian coastline. A large-scale numerical model that accounts for the presence of ice was developed to investigate storm surges in Canada’s western Arctic. It was found that the quality of the climatic forcing data used, ERA5, was poor in capturing peak wind speeds, but could be compensated for by using elevated wind drag coefficients. The use of non-traditional high-water marks such as driftwood lines were validated and were shown to significantly alter expected flood return periods compared to the return periods estimated from only the incomplete tide gauge measurements present on the Arctic coastline. The second case study extends the results of a tsunami hydrodynamic simulation on Canada’s Pacific coastline through a life safety assessment. The performance between an agent-based and GIS-based approach to modelling tsunami evacuation were directly compared and were shown to yield different magnitudes in fatality rate and facility demand, but similar trends. Both models agreed on a mitigation option that can significantly reduce the loss of life during a tsunami.