长江口北港近期河床演变分析与治理对策

根据20世纪70年代以来北港实测水下地形资料，全面分析了北港河段近期河床演变特征。分析表明，近期北港随着河宽的缩窄，河槽表现为淤滩冲槽，河道水深呈持续增大之势。长兴岛头护滩与圈围工程的实施，稳定了北港分流鱼嘴，但进口上游扁担沙尾时有沙体被切割下移，给北港稳定分流造成了极大的隐患。为了维护目前南、北港良好的河势条件，应及时加强扁担沙南缘及下边缘的固滩整治工程。

Analysis on recent evolution of Beigang branch of Yangtze River Estuary and its regulation countermeasures

Based on the measured underwater topography data of Beigang branch since 1970s,a comprehensive analysis on recent evolution characteristics of Beigang branch is carried out.The results show that with the decreasing of river width,the riverbed is scoured and the floodplain is deposited,and the water depth has a continuous increasing trend.The implementation of beach protection and enclosure protection of Changxing Island has stabilized water-diversion of Fish-mouth of North Channel.But the tail of Biandan sand shoal in the upstream of the entrance is being cut and moving downstream from time to time,which will become a potential threat to the stable water-diversion of Beigang branch.In order to maintain the river regime of Nangang branch and Beigang branch,the regulation and reinforcement must be carried out at the southern and lower edge of Biandan sand shoal in time.