Shoreline Movement Monitoring and Geomorphologic Changes of Beaches Using Lidar and UAVs Images on the Coast of the East Sea, Korea

Abstract

Sandy beaches are important habitats for coastal organisms and act as buffer zones during coastal disasters. Most of the coastal zone along the eastern coast of Korea consists of sandy beaches. However, beach erosion has been accelerating in recent years. In this study, shoreline movement and topographical changes were analyzed in Uljingun on the East Sea coast of Korea using remotely sensed data from airborne Lidar and unmanned aerial vehicles (UAVs). The shoreline changes extracted were statistically quantified using net shoreline movement (NSM) and linear regression rate (LRR) in the digital shoreline analysis system (DSAS). Morphological changes were quantified based on a comparison of the digital surface maps (DSM) generated by Lidar and UAVs. Shoreline movement and morphological changes were analyzed over the short-term (February 2016 to February 2019) and long-term (June 2008 to June 2018). Seaward migration was dominant for 7.02 m, 1.64 m, and 9.22 m along three defined subareas over the long-term. Over the short-term, LRR results showed landward migration as 0.7 m and 1.10 m in two of the subareas. Morphological change showed erosion and accretion occurring at approximately 0.08 m(3) and 0.42 m(3), respectively. This reverse trend indicates that a detailed DSM can detect volumetric change due to relocation of the sediment around artificial construction.