Applicazione di nuove tecnologie per il monitoraggio di ambienti marino-costieri

In my PhD project, two low cost detection systems have been tested: a marine one to acquire high resolution data in the bathymetric range between 0 and -10m and, a terrestrial to acquire high resolution data on the beaches. High resolution Side Scan Sonar data acquisition strategies have been developed in shallow water (-5 and -2.5m), capable of communicate integrating data acquired with non-oceanographic systems (Georadar “G.P.R.”). These integrations allowed us to study the emerged shallow and deep submerged areas, and to create very detailed cartographies of the seabed of the Alghero bay, of the Bay of Porto Conte (De Luca et al., 2018) and of the some areas of the Asinara island. In addition to the Side Scan Sonar and the Remote Operated Vehicle (ROV), the classic satellite detection systems have been used as well as high resolution images acquired with drones (UAVs). This latest technology, simple to use and very cheap, allows the creation of aerial photographs of marine areas close to the coast, where the oceanographic instruments, at the moment are unable to acquire data (depth less than 2.5 m). The information acquired made possible to evaluate the state of thePosidonia oceanicaseagrass, the coastal dynamics present in the Alghero harbour and to characterize two temporary storage sites used for the accumulation of the banquettes ofPosidonia oceanica. The coast of Alghero has a unique peculiarity in Sardinian realm, that is; the accumulations of Posidonia leaves. These per year are about 3000 m3, mostly concentrated in the beaches of San Giovanni, Maria Pia and Punta Negra. The large accumulations of leaves are a problem for the recreational use of the beach. The formed banquettes can frequently reach one meter in height, occasionally exceeding two meters. CurrentlyPosidonia oceanica(both leaves and banquettes) is moved by tractors and stored in temporary accumulation sites located near the beaches. For this reason, an action plan was prepared for the dismantling of the temporary storage sites of San Giovanni and Villa Segni. This was aimed to recover as much sand as possible the beach. The Ground Penetrating Radar (G.P.R.) was used to obtain information on the subsurface deposits in the San Giovanni are, to better correct management of thePosidoniaaccumulated leaves.The area has a surface layer composed of 10 to 50 cm ofPosidoniaresidues mixed with sand, overlying about 3 meters of sand. Between the layers, some wastes with an expiry date or production date were found, useful for stratigraphic dating. These analyses allowed us to establish that the temporary storage areas are not a dump sites and that an accurate managing of them could reclaim sand to the beaches.