T Batzella

Short-term evolution of the Budoni beach on NE Sardinia (Italy)

Dynamics and evolution trend in Budoni beach are described. The beach (long about 4km) is composed of fi ne to gravelly quarz sand, few seasonal lagoons are developed behind the dunes. Shortterm variations have been periodically monitored since October 09. Sedimentary and hydrodynamic characteristics were studied. Short-term evolution was tested using topo-bathymetric digital models, derived from data acquired in 3 different field; models of wave motion and hydrodynamics were created using Delft3D software. The results obtained from these models (wave ray direction, deep current distribution, structure and surfzone dynamics) allowed to visualize the response of beach to wind/waves stress, forced from NE, E, SE (wind intensity 18m/s, 10m/s). Gregale and Sirocco are the winds that generate the widest surfzone, the currents created by the these winds cause mainly longshore transportation in the early hours of the meteo-marine event. The beach shows an homeostatic behavior characteristics typical of balanced systems.

Coastal dunes vulnerability. GAVAM checklist method used at three mediterranean microtidal wave dominated beaches (Gulf of Cagliari)

The study shows the results achieved by using Geomorphology, Aeolian, Vegetation, Anthropogenic, Marine influences, (GAVAM) checklist, in three coastal dune zones of beaches located in southern Sardinia. The aim is the experimentation of reproducibility of GAVAM checklist in three Mediterranean microtidal wave dominated beaches.The studied dune zones are located at three Site of Community Importance (SCI) sites: ITB 042230 Porto Campana, ITB 042218 Stagno di Piscinni e ITB 040020 Isola dei Cavoli, Serpentara, Punta Molentis (southern Sardinia).By the application of GAVAM checklist the Partial Index Vulnerability (IVp) and the Dune Vulnerability Index (DVI) or total (IV) values are sequentially derived. IV index either partial or total ranges between 0 and 1, and as the index increases, the ability of the dune system to withstand further interventions decreases.The methodology has allowed an objective deduction to both potential vulnerability and the main source of imposed changes, as well major threats/stress factors have been assessed. DVI values range between 0.47 e 0.59 and indicate medium to high vulnerability.Moreover, the use of aerial photographs also highlighted the need for the implementation of the checklist using additional parameters related to fluvial-lacustrine processes and of particular anthropogenic activities.