MANAGEMENT OF ENVIRONMENTAL RISKS IN COASTAL AREAS

The present work deals with the assessment and management of environmental risk conditions in a typical costal area of Southern Italy. This area, located in the Salento peninsula, is subject to recurrent widespread instability phenomena due to the presence of steep rocky cliffs. Along the coast there are numerous beach resorts that are very crowded in the summer season. The environmental hazard deriving from the possible rock falls is unacceptably high for the people safety. Moreover, the land-based mapping of the dangerous natural structures is very difficult and time and resources expending. In this context, we carried out an UAV survey along about 1 km of coast, near the towns of San Foca, Torre dell'Orso and Sant' Andrea ( Lecce, Southern Italy). The UAV platform was equipped with a photogrammetric measurement system that allowed us to obtain a mobile mapping of the fractured fronts of dangerous rocky cliffs. UAV-images data have been processed using dedicated software (Agisoft Photoscan). The total error obtained was of centimeter-order that is a very satisfactory result. The environmental information has been arranged in an ArcGIS platform in order to assess the risk levels. The possibility to repeat the survey at time intervals more or less close together depending on the measured levels of risk and to compare the output allows following the trend of the dangerous phenomena. In conclusion, for inaccessible locations of dangerous rocky bodies the UAV survey coupled with a GIS methodology proved to be a key engineering tool for the management of environmental risks.