Sandy beaches characterization and management of coastal erosion on western Sardinia island (Mediterranean Sea).

Coastal erosion is a global problem, affecting sandy and rocky shores worldwide, and can be triggered by several causes. Local processes can generate erosion hot spots, whereas at the global scale, the main forcing are sea level rise, changes in storm climate and human interference. Beaches along the Mediterranean sea are strongly affected by coastal erosion. Recently, the Protocol on Integrated Coastal Zone Management in the Mediterranean (PAP/RAC 2007) recommended the prevention of the erosion processes by restoring the natural adaptive capacity of the coast and by improving the knowledge on the state, development and impact of coastal erosion. In order to achieve the objective of the PAP/RAC protocol, we characterized 24 sandy beaches along ~270 km of the western coastline of the Sardinia island (western Mediterranean). Grain size and mineralogy of the foreshore sediments were analyzed and the intertidal elevation/bathymetric profile was measured using Differential Global Positioning System. Aerial photos were used to identify the shoreline configuration, the number of bars and morphodynamic features. A digital elevation model (DEM)of the adjacent shelf was produced and acoustic backscatter, grab and box-corer sediment samples were collected in order to characterize the seafloor and to identify the substrate lithology, particularly the distribution of sandy sediments.The investigated coastline is characterized by linear, multibarred beaches and wide transgressive dune fields formed by terrigenous sand and coarse sand. These linear beaches are alternated with embayed beaches which locally show a mixed terrigenous/bioclastic carbonate composition. Large sandy bodies were found in the inner shelf, often forming dune fields uncovered by mud drape. A database was created to facilitate the characterization of the beach systems along the studied coastline and adjacent inner shelf. It is anticipated that the database will be used by policy makers in support of the implementation of coastal erosion management strategies.