 The effects of an artificial island on the geomorphic processes in the coastal area are complex and multi-scale. A unified, unstructured grid model and a topographic evolution model were employed to simulate the dynamics of the offshore environment under the influence of the artificial island. The results show that the coupling system with an unstructured mesh accurately reproduced the flow and sediment transport processes. Additionally, the contracted flow zone between the artificial island and the coastline, the runoff and the longshore current from the river, and the tidal flow from the ocean all contributed to shaping the local morphology around the artificial island. This modeling system, supported by parallel computing, can be used to study coastal environments with small-scale weighting structures. This article was authored by Guo Weifu, Jianli, Kun Yuan, and others.