长江口横沙通道演变对北槽深水航道上段回淤的影响

Study on the influences of fluvial processes of Hengsha Watercourse to deep water channel

根据长江口横沙通道1992-2013年海图及2013年含沙量、表层沉积物及床面微地貌等实测资料,分析长江口横沙通道演变及对北槽入口深水航道的影响,结果表明：二十多年来,横沙通道整体呈冲刷态势,北口刷深远大于南口,其原因主要由北港青草沙水库、北槽深水航道等工程所致;横沙通道中洪季平均水体含沙量为0.11kg/m3,且床面发育有大量不同形态尺度的沙波,波长在6.5~21m之间,波高在0.17~1.09m之间;目前推移质运动是横沙通道泥沙输移的主要形式之一,横沙通道河床刷深和推移质输沙对北槽深水航道上段圆圆沙航道淤积产生一定的影响。

The influences induced by fluvial processes of Hengsha Watercourse to deep water channel were studied based on the nautical chart from 1992 to 2013, the observed data of sediment concentration, sedimen- tation particles of the river bed, and the micro topography of Hengsha channel in the Yangtze River Estuary. Analysis of data shows that the overall trend of the Hengsha Watercourse was scouring over the past 20 years, and the north is the deeper than the south, which was induced by the engineering construction,such as Qing- caosha fresh water source project at North Channel and deepwater channel project at North Passage. The aver- age suspended sediment concentration is 0.11kg/m^3 in Hengsha Watercourse. There are different dune forms at the Hengsha Watercourse. The length of dunes is between 6.5 to 21m, and the height of dunes is between 0. 17 to 1.09m. One of main forms of sediment movement is bed load at present. As a result, the channel scour and bed load movement at the Hengsha Watercourse induced some influences on Deep-Water channel at Yuanyuansha at the North Passage.