Assessment of storm surge damage to coastal settlements in Southeast Florida

Coastal cities are growing at a very rapid pace, in terms of both population and physical assets, and great uncertainty surrounds the future evolution of hurricane intensity and sea-level rise. The combination of these trends will contribute to large financial losses due to property damage in the absence of specific protections. Southeast Florida represents a clear hot spot of coastal flood exposure: more than 5 million inhabitants live in the counties of Miami Dade, Broward, and Palm Beach, and the population is still growing. It is also a low-lying area where tropical hurricanes hit frequently. This article illustrates a methodology to assess coastal flood damage in urban settlements and it aims to determine more general lessons useful for all coastal cities. We consider the impact of different storm surges predicted by the SLOSH model and investigate flood risk considering different types of hurricanes. For each event, we apply a specific damage function and determine whether the considered storm surges potentially lead to an asset loss, considering both properties and their contents. The results show that, in the absence of protections, losses will be very high for large storm surges, reaching up to tens of billions of US dollars. In the second part of the analysis, we demonstrate how economic impact changes when protections are built up, considering different heights of protections. These results could be used as inputs into a robust decision-making process to determine the future of coastal protection in southern Florida.