Recently Unmanned Aerial Vehicles (UAVs), i.e. drones, have become a popular tool for aerial photography. In the framework of STENCIL we are now investigating how drone surveys could be used to monitor dunes and beaches.
In September the Ludwig Franzius Institute (LuFI), together with colleagues of the Alfred Wegener Institute (AWI), used a drone to survey 70 ha of coastal area in List on Sylt. In a controlled flight path, the drone is steered over a specific area and takes aerial photographs in regular time intervals. The flight takes about 30 min and almost 900 pictures of the surveyed area are saved. Afterwards the pictures are assembled to create a first 3D model of the beach showing the topography of the area.
In the next step the model will be calibrated and validated. GPS data will be linked to the model and used to complete any blank spots. Supported by the GPS data, the model can then be used to determine the volume of the dunes along the surveyed stretch of coastline.
The first preliminary results show that a UAV-based survey is a promising approach for the future monitoring of beach nourishments and their surroundings. The usage of drones is a simple, cheap and environmentally friendly method to survey the topography of a beach. Conducted in regular time intervals, the quick and simple method can help to identify erosion and to balance the sediment loss by nourishment. However, further investigations of the List model and other survey sites are necessary.