Analysis of S. João da Caparica beach vulnerability to a maritime storm event

Abstract

The morphological response of the S. João da Caparica beach, Almada, to the maritime storm Hercules that occurred in January/2014, was studied through mathematical modelling, for three of twelve topo-bathymetric configurations surveyed between 2008 and 2017: the two with the lowest and the one with the highest volume of sediment in the topographic part. This study aimed to quantify indicators of beach vulnerability, such as sand volume above three reference vertical levels, average and maximum retreat of two reference isobaths and maximum topo-bathymetric lowering, in order to provide guidance for future nourishment interventions. Hydrodynamic models at regional and intermediate scales were used to determine the forcing of the morphodynamic local model applied, XBeach. Besides the beach vulnerability indicators, the results revealed that the morphological configuration of the submerged zone plays an important role in the beach response when submitted to a storm with the characteristics of Hercules.