Event-based approach for probabilistic flood risk assessment

An event-based approach for probabilistic flood risk assessment for financial and civil protection applications is proposed. The risk parameters are evaluated in an event-based probabilistic framework for a set of hazard events and then all these results are probabilistically integrated, including, in a formal way, all uncertainties related to each and every part of the process. The hazard is defined as a stochastic or historic set of events, collectively exhaustive and mutually exclusive, that describes the spatial distribution, the annual frequency, and the randomness of the hazard intensity. The risk is expressed in different economic terms: the average annual loss, the pure risk premium, and the loss exceedance curve. As an illustrative example, this approach is applied to Acapulco city located on the Pacific coast of Mexico. These metrics are of particular importance for risk retention (financing) schemes or risk transfer instruments, and, therefore, they will be a particularly valuable contribution to further studies in defining strategies for financial protection against disasters. With these results, further results may be obtained for civil protection and land use applications.