Risk of Surface Sediment Erosion in the Bohai Sea, North Yellow Sea and Its Indication to Tidal Sand Ridge Occurrence

Abstract

Bottom geomorphological evolution and sediment distribution are under strong control of tidal forcing along China's coast. To quantify and assess the temporal-spatial change of bottom environment, a risk-based probabilistic concept of erosion is applied and maps of erosion risk are constructed. Sediment data categorized into 5 classes, together with hydrodynamic data in a temporal resolution of one hour and a model time of one month, are used to calculate the potential of erosion of surface sediments in the Bohai Sea, North Yellow Sea. Comparison with results of the tidal ellipse and bottom shear stress from model output shows that the highest risk of erosion is located in the Yalujiang Estuary, West Korea Bay, north of the Bohai Bay and in the surroundings of the Laotieshan channel of Bohai Strait, which may explain the occurrence of tidal sand ridges in the modeling domain.