# Wind-Wave-Current Coupled Modeling of the Effect of Artificial Island on the Coastal Environment
## 1 Introduction  
With the rapid development of society and economies in coastal areas of China, the contradiction between the shortage of land resources and development is becoming more and more prominent. Artificial islands became an effective method for human beings to expand production and living space into the sea and alleviate the human-land contradiction in coastal areas [1]. Hainan is a province seeing the rapid development of artificial island. According to statistics, from 2000 to 2014, Hainan approved the construction of 11 artificial islands, totaling 1845.34 hm\({}^{2}\). However, unreasonable land reclamation also brings about corresponding negative environmental and ecological effects, such as the decline in the quality of the marine environment, habitat degradation, destruction of the ecological balance, changes in the hydrodynamic environment, erosion and siltation of the shoreline, etc., which is particularly significant for sandy coasts and coastal areas [2; 3]. Under current national policy and because of the demand for the construct of an ecological civilization and basal restoration, research on the coastal erosion and siltation caused by artificial island is also being carried out by various scientific and technological workers. The traditional method is to use multi-stage remote sensing interpretation analysis to check the scale of the impact of the artificial island's construction on the adjacent coastline. For example, [PERSON] et al. [4] analyzed the changes in the coastline before and after the construction of an artificial island by using remote sensing image interpretation. [PERSON] [5] applied a one-dimensional coastal shoreline evolution model based on the principle of the conservation of mass to evaluate the development of changes to theerosion and siltation of the nearby shoreline before and after the construction of man-made islands. However, using remote sensing image analysis and one-dimensional simulation, it is difficult to understand the dynamic development process of artificial island' impacts on the nearby sea area at high spatial and temporal resolutions. Most studies on the stability of the shorelines of artificial island were carried out by establishing relevant numerical models and conducting a comprehensive analysis and evaluation of the influence of artificial islands on the stability of the shoreline through the simulation of regional wave, tide, and sediment change characteristics before and after the island's construction. [PERSON] [6] studied the feasibility of constructing an artificial island at the Pacific entrance of the Panama Canal in 2002. The artificial island was filled using earth excavated for the expansion of the Panama Canal. [PERSON] [7] studied the impact of Palm Tree Island in Dubai on the marine environment in the Persian Gulf in 2006. They analyzed the impact of artificial island construction on marine organisms and marine sediment movement and evaluated the compliance of artificial island construction with local marine environmental protection laws and regulations. In China, [PERSON] et al. [8] used the DELFT3D model based on a structural grid to discuss the influence of building sun and moon islands under different schemes on the hydrodynamic conditions and sediment transport in coastal areas. However, a structural grid is unable to reflect the complex coastline and local geometric features of artificial islands. [PERSON] and [PERSON] [9] applied the FVCOM model of ocean dynamics based on an unstructured grid to evaluate the influence of the proposed construction of the new Sanya Airport artificial island in Hainan Province on the surrounding hydrodynamics. The results showed that the unstructured grid model can accurately reflect the boundaries of local buildings and is suitable for simulating problems across physical scales, which can significantly improve the simulation accuracy. However, there is a nonlinear response relationship between artificial island and natural driving forces (such as typhoons and waves, etc.).