海床演变对山海关旅游海滩生态修复工程的响应特征

Effects of Ecological Restoration Project on Seabed Evolution at Shanhaiguan Tourism Beach

针对海滩侵蚀问题展开了包括滩肩补沙和离岸潜堤在内的海滩修复工程.为评估工程效果,采用Delft3D软件建立了山海关海域的泥沙输运和海床演变模型,使用2015年至2016年的实测资料验证模型.基于验证后的数学模型对工程海域泥沙输运与海床演变变化特征进行分析.结果表明:工程引起了近岸区域泥沙浓度的减小,减小幅度随离岸距离的增大而减小.工程建设前工程海域的侵蚀较为严重,工程的建设大大减小了近岸海域的冲刷深度,有效地保护了工程岸段海滩.工程后冲淤变化幅度第1年最大,然后逐年减少.

Aimed at protecting beach from erosion, a restoration project was developed covering beach nourishment and offshore breakwater. For assessment of the project, a model of sediment transport and bed evolution at Shanhaiguan Coast was established based on Delft3D and validated with field measurements from 2015 to 2016. Then, the model was used to investigate the influence of the restoration project on sediment transport and bed evolution. The results indicate that there is a lower sediment concentration after the restoration project is completed and the reduction of sediment concentration decreases with the increase in offshore distance. There is severe erosion before the restoration project starts and little erosion after the restoration project is completed. Hence, it is proved that the restoration project achieves the goal of beach restoration by reduction of erosion. The change of erosion and deposition after the project is the maximum in the first year, and then decreases year by year.