Flood Hazard Assessment Approaches for Climate Change (PAP014391)

Código

PAP014391

Autores

Monica Mannerström, Malcolm Leytham, Mariza Costa-Cabral, GUILHERME DE LIMA

Tema

Impact of climate change on flood risk

Resumo

This paper discusses different flood hazard assessment approaches to account for climate change in Western Canada. Three recent flood hazard assessment studies in British Columbia that accounted for climate change are presented. The study areas are quite different in terms of population, geophysical conditions and spatial extent, and each area will need to confront distinct flood hazards and flood management challenges. However, similarities also exist. The first study describes the Lower Mainland experience centered on the City of Vancouver on the south coast. With sea levels expected to rise by as much as 1 metre or more over the current century, increased flooding in the Vancouver area will primarily be a function of rising seas, increased storminess and coastal erosion. Rainfall, which is concentrated in winter, and is expected to become more intense, would challenge current drainage systems. The combination of increased river flows and rising sea levels will exacerbate flooding in coastal areas. The second case study is for City of Prince George, in the geographical center of the province. Flooding in the Prince George area occurs both in the early summer during snowmelt and during late fall or early winter during river freeze up. An understanding of the flood mechanisms is required to assess how the anticipated changes in temperature and precipitation may affect future flood hazards. The third example evaluates flooding at small aboriginal communities in the Coastal Mountains along the Lillooet River. The Lillooet River has seen unusually large peak-flow increases over the past several decades and an adequate future degree of flood protection must be determined for these isolated communities. Flood hazard assessment approaches for each of the three regions, and how they can incorporate the specific climate changes (including marine climate) that are projected for each region, will be reviewed. Recommendations for adaptive actions will be presented for each region. The flood hazard assessment approaches discussed in this paper are believed to be applicable to a number of locations.