Abstract

This study evaluates the impact of key factors of marine hydrodynamics, such as waves or currents on transformation process of topography, bottom and coast geomorphology in Truong Sa Island area of Truong Sa archipelago based on a continuous database of many years. MIKE model was used to calculate and simulate the impact of the wave and current on the sedimentation and erosion process that changes the seabed's topography. Calculated results show that wave height and flow rate compared to actual measured data of 73.5% and 60.6%, respectively, which are qualified according to Nash criteria. There is quite a large accumulation of sediment In the coastal area to the North, where the thickness of the sediment sometimes reaches 13 m and the accretion rate may sometimes be up to 0.3 m/day. On the other hand, erosion occurs along the south to the eastward coast, causing the sediment thickness to decrease from 5 to 10 m, sometimes up to 12 m. At a location 200 m north of the island, seafloor erosion is about 5 m to 8 m. The research results contribute the scientific basis for planning, advising and proposing the construction of marine defence works, as well as planning the maintenance and dredging of the channel to minimize the negative natural impacts, providing information for training, maneuvering and combat activities to ensure the effectiveness of the Navy's operations in remote islands.