长江口深水航道工程对盐水入侵的影响

长江口地区是我国经济发展的核心地带,但盐水入侵常常对当地的工农业生产及人民生活产生影响。对此,基于MIKE21水动力及盐度输移模块,建立了长江口—杭州湾大范围的二维潮流盐度数学模型,采用实测数据资料,在验证良好的基础上,探讨了深水航道治理工程对长江口盐水入侵的影响。结果表明,丁坝的修建改善了北槽水流条件,北槽上工程后盐度明显增大,涨憩时盐度变化最大,达6.4‰,北槽中大、中潮期间盐度工程后盐度增大,且在落憩时盐度增幅最大,达9.5‰,北槽下盐度亦有明显增加,但变幅相对较小;而南槽工程后盐度减小,且盐度过程线相对平稳;深水航道以北水域盐度等值线有前进趋势,而以南水域盐度等值线则有后退的趋势,杭州湾北岸水域盐度等值线工程后则略微前进。

Impacts of Deep Water Channel Project in Yangtze River Estuary on Saltwater Intrusion

The Yangtze River Estuary is the core area of China’s economic development,but saltwater intrusion often has an impact on the local industrial and agricultural production and people’s lives.Based on the MIKE21 hydrodynamic and salinity transport module,a two-dimensional tidal current salinity mathematical model of the Yangtze River EstuaryHangzhou Bay was established.According to the analysis of salinity change of the North trough and the South trough,the construction of spur dike improved the flow condition of the North trough,the salinity of the North trough increased obviously after the project,and the salinity change was the biggest when the project rose and fell,which reached 6.4‰.The salinity of the North trough increased after the project during the middle tidal periods,and the salinity increase was the biggest when the project fell,which was 9.5‰.The salinity of below the north trough also increased obviously,but the change range was relatively small.The salinity decreased after the South trough project,and the salinity process line was relatively stable.The analysis of the whole salinity field shows that the salinity isoline in the north of the deep water channel is advancing,while the salinity in the south is retrogressing,and the salinity isoline in the north coast of Hangzhou Bay is advancing slightly.