长江口北支近期河床演变分析

Analysis on recent evolution of North Branch Channel of Yangtze River Estuary

根据20世纪80年代以来北支实测水下地形资料,全面分析了长江口北支河段近期河床演变特征。分析表明:近期北支河床呈累积性淤积。在目前河势条件下,堡镇港以下崇明北沿边滩淤积速度将会加快;随着河宽大幅度缩窄,北支深泓线趋于稳定;为维持北支一定的水深,保障河道一定的航运功能,满足沿江两岸有关县市的引、排水需要,可对进口段进行一定的疏浚,适当增加分流比。

According to measured underwater topography data of North Branch since 1980s,a comprehensive analysis on recent evolution characteristics of North Branch Channel is conducted.The results show that the recent deposition in the riverbed of North Branch is accumulative.At downstream of Baozheng Port,the deposition rate along north-side beaches in Chongming Island is accelerating under the present river regime.With significant narrowing of river width,the thalweg of North Branch tends to be stable.In order to maintain a certain depth of the north branch,protect the navigation functions and meet requirements of diversion and drainage of the cities along the North Branch Channel,dredging should be carried out in the entrance reach to increase diversion ratio appropriately.