Shoreline Change Analysis using Airborne LiDAR Bathymetry for Coastal Monitoring

Abstract

Shoreline is commonly defined as the boundary between land and sea. As a consequence of global climate changes and human interventions, shoreline is constantly changing by erosion and accretion. Korea is also faced with the coastal erosion problem. Therefore, the coastal monitoring method needs to quantitatively analyze the shoreline locations and differences in past and present. For this, our research for coastal monitoring is to adopt the quantitative analysis of shoreline change using airborne bathymetry LiDAR. Bathymetry data is useful for coastal monitoring, since the water depth provide geospatial information of 3D point cloud data, including the shallow water as well as the near-shore. In this study case, bathymetry data was collected by CZMIL in 2013 at Gyeongpo and Wonpyeong beach. Topography data collected by ALTM in 2010 was used to check trend of shoreline change at the same sites. In order to extract shoreline position from the LiDAR data, the shoreline definition is referenced as AHHW (Approximate Highest High Water). As a result, East coast has eroded about 347 m(2) of Gyeongpo beach and about 23819.5 m(2) of Wonpyeong beach. From this analysis, the average annual rate of erosion is 1.6 m per year. Shoreline change at East coast resulted in a landward retreat by 5 m at the last four years.