南汇东滩圈围工程对长江口河势影响的数值模拟分析

Numerical analysis of the impact of the Nanhui East Tidal Flat reclamation project on river regime evolution in the Yangtze Estuary

基于验证的MIKE21软件长江口二维潮流数值模型,计算和重点分析了南汇东滩促淤圈围工程对长江口南槽、北槽和横沙通道的影响。结果表明:南汇东滩促淤圈围工程束窄了南槽下段河道,较大幅度地减小了该段的潮流量;但南槽中段以下河段流速增加幅度较大,河槽将会刷深,河势将得到发展;江亚北槽将会得到发展,北槽中段泥沙淤积现象将会加剧;横沙通道涨落潮流量大幅减少,横沙通道涨落潮流量与南槽涨落潮流量存在非常高的相关性,这对横沙通道作为航道开发和利用会带来较为不利的影响。

To study the impact of the Nanhui East Tidal Flat reclamation project on river regime evolution in the Yangtze Estuary,a two-dimensional tidal flow numerical model of the estuary was established based on the MIKE21model.The model was calibrated with field data and the analysis focused on the North,South,and Hengsha Passages.The numerical results show that after the reclamation project the tidal discharge greatly decreases and the velocity significantly increases in the South Passage due to a reduction in river width.This results in river bed scour and the river regime developing downstream from the middle of the South Passage.Although the Jiangya North Passage will be developed,the sedimentation in the middle of the North Passage will be intensified.The tidal discharge in the Hengsha Passage shows a high correlation with that in the South Passage and dramatically decreases.This may have a negative effect on the development and utilization of the Hengsha Passage as a navigation channel.These research results present significant scientific guidelines on both unpredictable problems in river regime control and the reclamation project itself.