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This work deals with the estimation of beach susceptibility to storminess in the Bay of Cadiz (SW Spain), and the concomitant environmental implications. For this purpose a comparison was made between the natural behaviour of beaches and the type and amount of coastal damage made by energetic waves in every beach type. Knowledge on the morphodynamic behaviour of beaches was obtained from a monthly topographic monitoring of 32 beach transepts normal to the coastline, performed during 30 consecutive months. Widely used morphodynamic parameters, like the Surf Similarity and the Surf Scaling parameters, were applied to the data, resulting in a general morphodynamic characterization of beaches, represented in a map of beach type distribution. Maximum coastal damage by storms was estimated by visual observations. Clear relationships between morphodynamic beach trends and amount of coastal damage have been obtained, and are presented in the form of a Beach Susceptibility Matrix. The matrix permits predictions of expected coastal damage associated with storms in other nearby beaches by means of a simple beach monitoring programme. [ABSTRACT FROM AUTHOR]

Variations in the disturbance depth were measured across four open mesotidal beaches on the Gulf of Cadiz coast of Spain during single tidal cycles, using rods and plugs of marked beach sands inserted in the foreshore. The studied beaches show a wide range of morphological variations and are distributed along a broadly homogeneous straight coast where energetic conditions remain more or less constant. Several parameters like wave height, beach gradient and grain size distribution have been compared with the variability of the recorded disturbance depth. As a conclusion, it is suggested that the morphodynamic regime is the characteristic that best explains the spatial variation of the disturbance depth, as well as the different response of the beaches under broadly similar energetic conditions. Three main morphodynamic classes have been observed in the studied beaches: reflective, barred dissipative and dissipative. In each case the morphodynamic situation controls the distribution and relative intensity of wave processes acting across the beach profile and, hence, the different rate of disturbance depth. The morphodynamic study of a beach permits an initial prediction of its morphological response under variable wave conditions. [ABSTRACT FROM AUTHOR]