Lidar and UAV system data to analyse recent morphological changes of a small drainage basin

In this paper, the preliminary results of an integrated geomorphological study carried out in a 1.6 ha catchment area located on the eastern side of the Crati River valley (northern Calabria, South Italy) have been presented. An orthophoto and shaded relief map of the study catchment, obtained by 288 unmanned aerial vehicle (UAV) images, integrated with field geomorphological surveys have been used to produce a detailed map of landslides and water erosion phenomena. The study area is characterized by active morphodynamic processes that result in the occurrence of water erosion phenomena and several landslides. In particular, 29 slides and 37 earth slides that evolve into earth flows have been recognized. Spatial and temporal development of geomorphic processes (erosion/depletion and sedimentation/accumulation) have affected the catchment area in the last seven years. Indeed, the comparison between light detection and ranging digital terrain models (LiDAR-DTM) of 2012 and UAV-DTM of 2019 showed depletion values between -0.01 and -5.76 m, with a mean value of -0.96 m; whereas for the accumulation the mean value is 0.94 m, with a maximum thickness of the deposited material of about 2.98 m. The results obtained highlight the usefulness of the methodology to provide detailed information on geomorphic processes and related short-term landscape development in a small drainage basin.