Estimation of storm surge inundation and hazard mapping for the southern coast of Korea

Abstract

The coastal area of Korea is damaged by the approach of typhoons every year. The most serious inundation damage, with loss of lives and properties, was caused by typhoon Maemi in September 2003. After this event, there has been increased interest in addressing these coastal zone problems. It is therefore desirable to accurately forecast the storm surge height. In this study, using a numerical finite-volume coastal ocean model (FVCOM), a storm surge was simulated to investigate its inundation characteristics for the coastal area at Masan, Yeosu and Busan cities on the southern coast of Korea. In the model, a moving boundary condition (wet-dry treatment) was applied to examine inundation propagation by storm surge. The model grids were extended up through the lowland area by applying the DEM, made by precisely combining the airborne-LiDAR survey and bathymetry data. A minimum 30 m resolution unstructured triangular mesh was applied to calculate the storm surge and inland inundation. Simulated inundation range and depth were compared with the inundation map made from field measurements after the typhoon event. The results of inundation simulations in this study show good correspondence with not only the observed inundation area but also inundation depth. We also estimated the special inundation level distributions for each return period. The numerical model system adopted in this study could be a useful tool for analyzing storm surges, and for predicting coastal inundation. In addition, it is necessary for preparing detailed evacuation plans, including hazard maps for associated storm surge inundation problems.