Utility of Morphodynamic Characterisation in the Prediction of Beach Damage by Storms

Abstract

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.