围垦工程影响下的淤涨型潮滩演化:以江苏弶港潮滩为例

The geomorphologic response of accreting intertidal flat to reclamation: a case from Jianggang, Jiangsu

通过对受到围垦工程影响的江苏弶港海岸两条潮滩剖面的多期高精度实测高程及沉积物粒度数据进行分析,探讨淤涨型潮滩剖面对围垦工程的响应特征及剖面演化模式。结果表明,在物源充足的淤涨型潮滩围垦,可导致沉积物在围垦堤附近海域快速堆积、沉积物粒径变细;离海堤越远,沉积速率及沉积物粒度参数的变化越不显著。围垦堤附近海域是潮滩低能区,沉积物在此汇聚,造成潮滩剖面凸点的向岸迁移及双凸型剖面的塑造。另外,大型潮沟及其迁移也是影响剖面发育的重要因素。未来需结合海平面变化,研究围垦背景下的长周期潮滩演化趋势。

On the basis of the high-resolution elevation and grain size data collected from intertidal flats at Jianggang （Jiangsu） coast, we distinguish the geomorphic response of accreting intertidal flat to reclamation, and also proposed a conceptual model. The results show that reclamation at upper accreting intertidal flat with sufficient sediment supply could resuh in fast fine sediment accumulation outside the sea wall. However, sedimentation rates and sediment grain size parameters change none significant far from the sea wall. The upper intertidal flat changes into low energy status due to the sea wall construction, which results in sediment accumulation with a maximum sedimentation rate. Thus, the convex point of tidal flat profile would move towards sea wall and then a dual convex profile could develop. In addition, large-scale tidal creeks and their migration are important factors changing the profile shape of intertidal flat. In the future, the long-term evolution of intertidal flat due to sea level changes is required the long-term climate change study.