Abstract: Tieshan Bay is located in the northeast Beibu Bay. It has clean water and long shoreline. In this study, a two-dimensional (2-D) hydrodynamic model and a 2-D advection-diffusion model were set up to simulate the water exchange capability before and after the port construction in Tieshan Bay. The 2-D hydrodynamic model was verified by measured data, and the 2-D advection-diffusion model was used to calculate the half-life time of different area in Tieshan Bay. The simulation results show that the water exchange capability of Tieshan Bay is strong; and that before the port construction the half-life time of water exchange is 129 days and the water exchange capability is mainly affected by tidal action. The strong tidal action, large tidal range and wide harbor entrance all provide good conditions for the water exchange in Tieshan Bay. After reclamation the half-life time of water exchange would be 142 days, just 13 days more than before, so the port construction should have little effect on the water exchange capability of Tieshan Bay.

Key words: Tieshan Bay, water exchange, port construction, half-life time, tide