SWASH BAR BEHAVIOUR ON A PROTECTED MICROTIDAL BEACH: LIDO DI DANTE, ITALY

The morphodynamics of a microtidal protected beach during medium-wave energy conditions is examined in this paper. The significant wave attenuation due to the inshore protection structures permits to assess the action of swash processes on swash bar morphodynamics. Under very low energy conditions (Hs < 0.1 m) no significant morphological changes were observed. However, the swash bar situated in the upper part of the intertidal beach migrated landward by ~ 1m/tide during two consecutive tides when the significant wave heights were around 0.4 m. The migration processes ended in the change of the morphology of the swash bar from a low-amplitude bar to a slip-face ridge. A high resolution shallow water model (SWAN) was used with the local wind and wave measurements to produce wave induced force (WIF) vectors predictions over the study area. A significant relationship between the WIF vectors thickness and bed response was found