Effects of offshore artificial islands on beach stability of sandy shores:case study of Hongtang Bay,Hainan Province

Artificial island-type reclamation often exerts certain impacts on near-shore sandy shoreline resources and coastal ecological landscapes.The relationship between artificial islands and offshore beach evolution has attracted considerable attention in coastal protection and engineering construction.In this study,we consider Hongtang Bay in Hainan Province,China,as the research object.We adopted the Gao-Collins model to investigate the substrate transport trend in this sea area based on the analysis of the measured hydrologic and sediment data.The shore section from Nanshanjiao to Hongtangling(Taling),including the flat and straight shore sections,is dominated by the lateral transport trend of the vertical shore.The near-shore water has a strong lateral sediment transport capacity,while the outer deep-water area exhibits a sediment transport trend consistent with the tidal current movement.Using multi-year topographic data,the shoreline and seabed alterations in Hongtang Bay were analyzed,and the LITLINE beach evolution model was adopted to simulate the effects of three artificial island layouts with different island filling areas,offshore distances,and plan forms on the near-shore shoreline deformation.The results obtained indicate that the artificial island arrangement with a large offshore distance and a small area has relatively substantial advantages,such as minimizing the adverse effects of artificial island implementation on the near-shore beach.