长江口北支水道水沙特性分析

Analysis on flow and sediment characteristics of north branch of the Yangtze estuary

从实测资料出发,结合水流数值计算成果,对长江口北支水道的水流、泥沙和含盐度等资料进行分析,得出了北支水道的水沙特性,并分析了水沙变化与河床变化的相互关系。北支水道在1958年南通河段河势控制后,径流分流比逐年下降,并渐趋稳定于3%左右。北支水道受径流影响越来越小,主要受潮流作用。随着水沙特性的逐年变化,北支水道0m以下槽蓄容量逐年减小,并渐趋稳定,北支上段为逐年淤积最快的区域。由此反过来影响了水沙条件的进一步变化,使北支上段平均潮差增加,北支的会潮点由崇头附近下移至青龙港附近。

Based on surveyed data and combined with numerical computation results of flow, the analysis on the data of flow, sediment and saline concentration etc. of north branch of the Yangtze estuary was carried out and the flow-sediment characteristics of north branch was obtained. The interrelation of flow-sediment variation and river bed variation was also analyzed. After river regime of Nantong reach was controlled in 1958, flow diversion ratio decreased year-by-year and gradually stabilized at 3% or so. The influence of stream flow on the north channel becomes less and less and tidal influence becomes major one. Along with the year-by-year variation of flow-sediment, the channel storage of the north branch under elevation 0 m decreases gradually and tends to stable, the upper reach is the fastest silting area in the north branch. The river channel variation inversely influences further variation of flow-sediment condition, causing the average tidal range increases, the confluence point of tide and stream flow moves down from nearby Chongtou to Qinglong port.