Catastrophic beach erosion induced by littoral drift on nearby beach after Samcheok LNG's massive coastal reclamation project

Abstract. Large-scale construction projects, such as port construction and reclamation endeavors, can alter inshore wave dynamics, leading to severe coastal erosion. In South Korea, recent large-scale reclamation projects have resulted in the catastrophic erosion of sand along nearby coastlines. This study focuses on Wolcheon Beach, where the complete sand loss occurred due to robust longshore sediment transport (LST) induced by a reclamation project for the construction of the nearby Samcheok liquefied natural gas (LNG) terminal in Gangwon Province. A shoreline change model was employed to simulate this phenomenon, and the results were validated using satellite imagery. The model accuracy was assessed by comparing the LST rate vectors indirectly estimated from the changes in the shoreline delineated in satellite images with those directly derived from the model. Furthermore, a response methodology was proposed using the parabolic bay shape equation, which can effectively mitigate coastal erosion by controlling LST by installing a small-scale groin group on the adjacent beach before commencing reclamation or port projects. These findings are anticipated to significantly contribute to averting catastrophic coastal erosion issues, such as those witnessed at Wolcheon Beach, before performing large-scale construction in coastal regions.