近年来,随着长江流域来沙量的减少,河口水沙动力条件以及河床地形必将发生一定程度的变化。通过对长江口南、北港河道连续9d小潮至大潮水沙定点观测发现,小潮期含沙量较低,但随着潮流速增强,大潮期含沙量较高,表明泥沙再悬浮明显。通过实测数据分别给出大、中、小湖南、北港河道挟沙力经验公式,显示出潮流与含沙量具有良好的相关性,同时显示出潮流流速与挟沙能力的方次变化有良好的对应性。
In recent years, the hydrodynamics and riverbed topography of the Changjiang River Estuary is inevitably experiencing some new changes due to the decrease of the runoff and sediment load. Successive 9- days fixed point observations during neap-mean-spring tide show that the sediment content was relatively low for neap tide, increased with the increase of flow velocity and was higher for spring tide, which indicated evident sediment resuspension. Analysis of the observed data gave out empirical formula of sediment carrying capacity of neap, mean and spring tides for the South and North Channels of the Changjiang River Estuary, and showed good correlation between the sediment content and tidal current, and also good correspondence of their power changes.