长江口北槽深水航道工程对九段沙冲淤影响研究

Study of influence on erosion and accumulation of Jiuduansha Tidal Island by Deep-Water Channel Project at North Passage of the Yangtse River

根据1989～2003年长江口九段沙附近地形图,在地理信息系统软件MapInfo的支持下,分析了北槽深水航道工程对九段沙冲淤演变的影响.在长江来沙减少总的情势下,九段沙总的淤积速率在明显下降,但北槽深水航道工程使局部冲淤形势发生逆转:九段沙顶端到江亚南沙大片区域淤积速率显著增强,沿北槽深水航道南导堤外缘形成一个10 km长的淤积带;九段沙东侧水下三角洲受工程的影响不大,淤积速率持续降低并底端发生冲刷.

Based on the topographic map of 1989 - 2003 around the Jiuduansha tidal island at the mouth of the Yangtse River and supported by the software of Maplnfo, this paper has analyzed the influence on the erosion and accumulation of Jiuduansha by the deep-water channel project at the North Passage. The purpose is to find the change of its erosion and accumulation under the project. It is found that with the reduction of bedload from the Yangtse River in general, the silting speed of JiuDuanSha is evidently falling, while the project has made it reverse in some areas： the silting obviously speeds up from the top of Jiuduansha to Jiangya South Shoal, which forms a silting strip about 10 km along the south bank of the passage; meanwhile, a little effect occurs on the delta under the water east to Jiuduansha; the depositing speed continues to fall and erosion appears down to the delta.