Coastline Change Measurement Using Shipborne Mobile LiDAR in Anmok Beach, Gangneung, Korea

Abstract

Coastal areas, used as human utilization areas like leisure space, medical care, ports, and power plants, etc., are regions that are continuously changing and interconnected with ocean and land. Regular monitoring of coastline changes is essential at key locations with such volatility. For effective monitoring coastal changes, KIOST (Korea Institute of Ocean Science & Technology) has constructed a shipborne mobile LiDAR system. The shipborne mobile LiDAR system, installed in a research vessel, comprised a terrestrial LiDAR (RIEGL LMS-420i), an IMU (MAGUS Inertial+), a RTKGNSS (LEICA GS15 GS25), and a fixed platform. The shipborne mobile LiDAR system is much more effective than terrestrial LiDAR systems for the measurements without shadow zones in foreshore areas. We conducted coast area measurements at January 2016 (winter season) and September 2016 (summer season) in Anmok Beach, Gangneung, Korea. The study area is located in the north of the Gangneung port. Coastal erosion occurs frequently in the study area and coastal terrain changes continuously. Based on the measured mobile LiDAR data, the coastline of the Anmok Beach was extracted. Compared to the winter coastline, the summer coastline has undergone many changes. The shoreline curvature of the summer was larger than that of the winter and the summer coastline alternated between landward migration and seaward migration in the northern part of the study area. In the southern part, the landward migration of the shoreline mainly appeared. The concomitant wave data, including wave directions, significant wave height, and energy spectrum, showed strong correlation with the coastline change. The statistical results of high wave data indicated that high waves coming from NNE and NE in winter and from ENE in summer were dominant. Effective monitoring of the coastline changes using the shipborne mobile LiDAR system will be able to contribute to coastal erosion management and response.