Numerical Simulation of Hydrodynamic Processes for East Shantou Reclamation Engineering

A wave-current coupled mathematical model (MIKE21) was adopted in this paper to simulate the hydrodynamic changes (tidal level, tidal current, wave field) in the coastal waters surrounding the reclamation project of the Eastern Urban Economic Belt in Shantou, before and after the project implementation. The results show that: (1) Tidal level: After reclamation, the tidal level in the project area changed slightly within a range of 2~4 cm; the offshore low tidal level was 1~2 cm lower than pre-project. Shantou Port waterway’s high tidal level increased by 2~4 cm and low tidal level decreased by 2~4 cm, mainly caused by channel dredging. (2) Tidal current: The flood current velocity in the reclamation area increased with a changed direction; during ebb tide, the ebb current velocity increased at Xinjin and Waisha River estuaries, decreased along the reclamation coast, and increased in southeastern waters of Laiwu Island (flow direction unchanged). The reclamation had little impact on the waterway’s tidal current. (3) Wave field: Pre-project, natural horn-shaped coastline and barrier shoals induced nearshore wave refraction/breaking, with significant wave height of 0.0~0.2 m (nearshore) and 0.4~0.8 m (offshore). Post-reclamation, the straight artificial coastline and local sand extraction pits reduced wave energy loss, but the absence of shoals and topographic changes led to wave energy concentration in the reclamation front, with H₁/₃ increasing by 0.1~0.3 m (most notably at the two estuaries, rising from 0.0~0.2 m to 0.2~0.4 m). The research results reveal the influence mechanism of the reclamation project on the hydrodynamic environment of the coastal waters around the Eastern Urban Economic Belt in Shantou, and provide technical support for the feasibility evaluation of the construction project and the marine environmental risk management and control of the Eastern Urban Economic Belt in Shantou.