A Method of Identifying Coastal Dunes in Front of Cliffs by UAV Mapping—An Application to Omotehama Coast, Aichi Prefecture, Japan

This study provides a method to identify coastal dunes in front of sea cliffs as part of the study of the dunes (Hsin et al. in JSCE Ser B2 Coast Eng 78(2), I_523-I_528 (2022)). Sand dunes in front of sea cliffs are special type of coastal dunes, where the cliffs behind the dunes built them up. Coastal dunes not only have the function of coastal protection to prevent waves from directly eroding cliffs, but also serve as ecological preservation and amenity. Dunes under sea cliffs need to be effectively surveyed because they are often located below the cliffs and are not easily accessible. This study was conducted for the Omotehama coast of the Atsumi Peninsula, Aichi Prefecture, Japan. The dune complex here has various growth periods, including incipient, established, mature, and erosion periods. This makes it an excellent place to examine the dunes in front of the sea cliffs. In this study, coastal images were taken by real-time kinematic (RTK) drones, and coastal digital surface model (DSM) was produced using the structure from motion (SfM) method. The slope analysis was performed, and various characteristics of the dunes in front of the sea cliffs were extracted, such as the boundary of the dunes, the water flow, and the erosion by waves.