Coastal dunes vulnerability indexes: a new proposal and aplication to Ria Formosa Coast (Portugal)

Abstract

In the present work it is proposed a new coastal dune vulnerability index based on its exposure (and resistance) to overwashing and erosion under storm events, focusing solely on the short-term events. The methodology is applied and validated against the available data for the Ria Formosa (Algarve, Portugal) coastal beaches. The overwash index is determined as a function of the dune crest height in relation with the maxima water levels for different return periods, and the storm-erosion index is computed as function of the remaining beach/dune volume after the impact of the 10-year return period extreme-wave conditions in relation to the pre-storm volume. It is discussed the results of this application, enhancing the necessity of further validation.