A methodology to estimate storm-induced morphodynamic risks is presented. The storm-induced coastal response is separately assessed in terms of inundation, beach profile and transport potential. Inundation is calculated by means of the run-up Ru2% at the peak of the storm. Erosion is characterized by the eroded volume from a beach profile and, overall sediment transport is parameterized in function of the integrated wave power during the storm impact. These three parameters are used to calculate the resulting risk by estimating their probabilities of occurrence using the event and response methods. In the first one, the probability of occurrence is assigned from the extreme wave distribution (events) which is used to calculate the corresponding morphodynamic processes. In the response approach, storm wave data are used to build a data set of storm-induced responses which are later fitted to an extreme distribution. These two methods have been applied to characterize storm wave-induced morphodynamic risks at Costa Brava (NE Spanish Mediterranean coast). Results show that for this case, the use of the event approach significantly under-predicts the morphodynamic response for any probability of occurrence and, in consequence, its use will under-predict storm risks.
