Assessing the costs of coastal inundation
Using customised models, we assessed the extent of potential flooding and flood damage, including wind and storm surge, to the inundated area for current and future climate change scenarios.
Climate change is aggravating the risks of coastal inundation through an increase in sea level and the potential changes in storm surges, driven by changes in cyclone frequency and intensity. This could cause an increase in damage to coastal properties over time if business as usual prevails. For this project, we assessed the potential damages for the coastal area of Baie du Tombeau in Port Louis, Mauritius.
Using our methodology from an earlier project in the Pacific Ocean, we modified our approach for the Baie Du Tombeau area. We applied customised models for the analysis of flood damage potential.
Data is never perfect, so it was necessary to be able to work with locally available data that wasn’t in a format that could be readily applied and identify the inputs and proxies used when inputs weren’t readily available. We looked at how these inputs are used to assess the flood level and the extent of flooding. From this, we could identify the expected damage to the properties in the inundated area for both the current situation and a future climate change scenario.
Our analysis of wind and storm surges was distinctive in this case, as world-class model applications and probability assessments could be made that provided transparency for decision-makers when considering adaptation options.
Our report was written as part of the Islands Project, supported by the Indian Ocean Commission. It outlined 1-in 50-year event changes, the annual expected damages, and the projected increase in damages from more frequent extreme events. Although no adaptation options were evaluated for their cost-benefit characteristics, the US$1.7 million increase in damage costs (recurring yearly) formed a benchmark against which adaptation decisions could be evaluated.