Coastal flooding in the Peel Harvey Estuary and the effects of mean sea level rise

With global mean sea levels expected to rise rapidly throughout the 21st century, there is potential for an increased likelihood of coastal flooding around many of the world's coastlines. Mandurah, located on the southwest coast of Western Australia, is especially vulnerable to coastal flooding as canal estates and lowlying land around the Peel Harvey Estuary place a large portion of the population and infrastructure in this region in flood prone areas. An increase in the number and scale of extreme sea level events could prove extremely destructive for the city. The aim of this study is to assess the exposure of the Peel Harvey Estuary to coastal flooding under present conditions and possible future sea-level rise scenarios. A high-resolution process-based numerical model of the estuary has been configured using the Mike21 modelling suite. The model was validated against five tidal gauges in the estuary. The extent of inundation around the estuary has been assessed for mean higher high water tide conditions and several extreme sea levels ranging from 1 in 1 to 1 in 1000 year events. These scenarios have also been analysed with reference to future changes in mean sea level of 0.5, 1.0 and 1.5m.