长江口深水航道治理一期工程实施对南槽冲淤演变的影响

根据长江口深水航道治理一期工程开工以来南槽的多次地形资料和分流比资料,详细分析了一期工程实施以来南槽河床的冲淤变化。结果表明:随着一期工程的实施,南槽上段的水流动力不断增强,河床刷深,深槽展宽。南槽中、下段受南槽上段冲刷、底沙下泄的影响,曾出现阶段性的淤积,但随后河床水深便得以恢复。1998-2003年南槽上段共冲刷近0.85亿m3泥沙。一期工程完成后,南槽上段和中、下段季节性冲淤规律不同,上段洪冲枯淤,中、下段洪淤枯冲,季节性冲淤幅度通常都在0.7m以内。南槽南、北两侧的南汇东滩和江亚南沙在淤涨的同时,也分别呈现出洪冲枯淤和洪淤枯冲的季节性变化规律。

Effect of the implementation of the first-stage project of the deepwater channel regulation in the Yangtze River Estuary on the erosion and deposition in the South Passage

Based on the topographical maps and the flow discharge ratios of the South Passage, the erosion and deposition of channel bed in the South Passage after the implementation of the first-stage project of the deep-water-channel regulation in the Yangtze River Estuary is studied. The results show that channel bed erosion happened in the upper reach of the South Passage after the implementation of the first-stage project, and the channel bed in the middle and lower reaches of the South Passage exhibited deposition first and then erosion. The total sediment eroded from the upper reach is nearly 8500 million m3 during the period of 1998 to 2003. Besides, the upper reach of the South Passage appeared erosion in flood seasons and deposition in non-flood seasons, meanwhile the middle and lower reaches exhibited deposition in flood seasons and erosion in non-flood seasons. Generally, the seasonal erosion or deposition intensity is less than 0.7m.