Relazione tra idrodinamica e processi di sedimentazione nella spiaggia di Santa Margherita di Pula (Golfo di Cagliari – Sardegna Sud-Occidentale)

This paper presents the monitoring survey results in Santa Margherita di Pula beach (SW of Cagliari Gulf ) between 2006 and 2007. The aim of this study was to evaluate the beach dynamic on foreshore and drybeach which have been realized by sediments analysis, periodic morpho-bathymetrical surveys and by studying hydrodynamic models which simulated the responses of the coastal environment subjected to different swell events. Sediments analysis, periodic morpho-bathymetrical surveys and hydrodynamic models, which simulated the responses of the coastal environment subjected to different swell events, were analysed in order to evaluate the foreshore and drybeach dynamic. Drybeach - foreshore morphology models combined with summer – winter settings allowed a better understanding of sedimentary processes and enabled to evaluate the resulting profiles and the sand volumes distribution (height, slope, dune ridges, berms, shoreline, bars, troughs, etc.). The Sirocco wind events (120°) were the most significant. Sediment samples were mainly classified as “medium sands” with siliciclastic composition. Furthermore Santa Margherita beach is caracterized by several anthropic infrastructures, which influence the sediments distribution and suggest to simulate his evolution trend (accretion, equilibrium, erosion). Santa Margherita beach was classified as “intermediate-dissipative”. Bars and troughs zone(surfzone) can extends up to 500 m from the shoreline. The beach shows a stable structure while presenting seasonally marked variations.