Beaches Morphological Variability Along a Complex Coastline (Sinis Peninsula, western Mediterranean Sea).

Wave climate, sediments, topographic features and tides influence the morphology and the short-term dynamics of beaches. The interactions between these different forcings affect the features of the beach system. In this work the morphological beach responses in relation to the most energetic period of the year were studied in a coastline with high geomorphological complexity. Three beaches, located along the Sinis Peninsula (western Mediterranean Sea, western Sardinia), were monitored for about 6 months. In order to estimate morphological changes, repetitive beach profiles were acquired by means of Differential Global Positioning System. Wave data were collected by an offshore wave buoy and the grainsize features of each beach was determined. A coupled 3D hydrodynamics-wave, finite element model was also applied in order to investigate the current dynamics and the wave propagation along the selected coastal area. During the monitoring period, the beaches experienced relevant changes when consecutive storms occurred. In sediment deprived embayed beaches, the presence of headlands interacting with waves, favored beach rotation and lead to a crenulate shape of the shoreline. In addition, on sediment abundant beach, cross-shore sediment transport and simultaneous shoreline retreats were observed during storms events. Finally, the effects on the wave heights and directions, due complex coastline features of the Sinis Peninsula, were discussed in relation to the morphodynamics response of each beach.