SWASH ZONE MORPHODYNAMICS OF COARSE-GRAINED BEACHES DURING ENERGETIC WAVE CONDITIONS

Abstract

A 2D laser-scanner was deployed on four different coarse-grained beaches (Chesil, Loe Bar, Hayling Island and Seascale - all in UK) to measure the swash morphodynamics during energetic wave conditions (offshore Hs > 2m). Field observations performed with the laser-scanner showed that different types of coarse-grained beaches present contrasting morphological responses under energetic hydrodynamics. The surf scaling parameter, a proxy of the morphological condition and wave steepness on the swash, showed an inverse relationship with the extreme vertical runup illustrating that runup is enhanced by low steepness swell waves for a given coarse-grained beach\slope; nevertheless additional parameters are needed to explain the entire runup variability.