摘要：
Tidal inlet, which connects water inside and outside a bay, and maintains water exchange and channel's navigation, is the core and foundation of an inlet system. Based on observational data, sea charts and topographic maps, the hydrodynamic and sediment transport processes affected by natural and human activities in Zhelin Bay were studied with SELFE (semi-implicit Eulerian-Lagrangian finite-element) model, and the evolutions of the tidal inlets were revealed. It was confirmed that tidal areas of Zhelin Bay with 125 km2 before the reclamation were independent and large for each inlet, whose stability was maintained. After the 1970s, the reclamation made the tidal water areas dropped to 50%, the hydrodynamic structure of tidal inlets changed accordingly, and the suspended sediments from the outside of the bay transported into Zhelin Lagoon and deposited into the Sanbaimen Channel. The tidal area of Xiaojinmen Inlet changed little, so the hydrodynamic and sediment transport of inlet was still ebb-tidal dominant. The circulation of Xiaojinmen Inlet was enhanced, which resulted in the adjustment of erosion and deposition. The tidal area induced by Dajinmen Inlet dropped 1/3 to 40 km2, which weakened the asymmetry of flow velocity. The circulation of Dajinmen Inlet promoted the deposition in the west and the erosion in the east of the inlet section. The tidal area of Xiaomen Inlet collapsed by more than half, which resulted in narrowed inlet width,extended length and shallower water depth; and the circulation between Dajinmen Inlet and Xiaomen Inlet intensified the deposition and instability of Xiaomen Inlet.%潮汐汊道是连接内湾和外海、维持港口通航和水体交换的枢纽, 其演变特征是整个澙湖、海湾地貌体系研究的基础.选取典型多汊型潮汐汊道系统——柘林湾为研究对象, 以实测资料和历年海图、地形图为基础, 结合 SELFE (semi-implicit Eulerian-Lagrangian finite-element)模型,研究多汊型潮汐汊道水动力结构、泥沙运动及自然和人类活动影响下的演变特征.结果显示, 20世纪70年代澄饶大联围之前,共享柘林湾125km2纳潮水域的5个汊道同时维持稳定;围垦工程后, 西侧 2 个汇潮口门封闭, 纳潮面积减少 50%, 导致湾内动力减弱, 韩江来沙中断, 湾外浅滩冲刷, 泥沙向湾内输送, 30多年来三百门水道显著淤积,小金门稳定,大金门冲淤调整,小门水道淤积不稳.围垦工程后小金门水道的纳潮面积变化甚少, 水动力及输沙仍为落潮占优, 汊道环流发育, 汊道断面冲淤微调, 维持稳定; 大金门汊道所控制的纳潮面积减小 1/3, 口门涨、落潮流速不对称性减弱, 汊道冲淤调整; 小门水道纳潮面积剧减一半以上, 汊道延长弯曲,大金门与小门水道的环流结构加剧了该汊道的淤积和不稳定.
