Multitemporal analysis of coastal dynamics by high-resolution reconstruction of topography using UAVs

Dynamic networks of Unmanned Aerial Vehicles (UAVs) can be used in a broad range of missions like monitoring and surveillance of the coastal environments to detect shoreline changes. The aim of this study is to evaluate topographic changes along a stretch of coastline in the Silivri, which is outside metropolitan Istanbul (along the Sea of Marmara) in Turkey, by means of an UAV coupled with Structure from Motion (SfM) and multi-view stereo techniques. This region was surveyed over 11 months from September 2016 to July 2017 in order to produce digital elevation models and orthophotos of the coastal area by using dense point clouds. Changes in the shore topography associated with usual tide and human activities were assessed in terms of sediment activity and wet±dry boundary shifting that defines the shoreline. The results showed that UAVs can be used for regular coastal monitoring purposes and that they can provide new insights into the processes related to natural and/or human-related topographic coastal changes.