长江口深水航道减淤工程实施效果评价

Evaluation on effect of silting reduction project in deep-water channel of Yangtze Estuary

为降低长江口深水航道常态回淤量,分先期工程和完善工程两阶段实施长江口深水航道减淤工程南坝田挡沙堤加高工程。利用北槽深水航道减淤工程实施前后的实测数据,综合分析了工程实施前后水沙通量、含沙量、流场、周边河势、航道减淤等方面的变化情况。结果表明:1)先期工程实施后,南导堤涨潮越堤水沙显著减少,北槽含沙量明显降低,航道南侧横向水沙输移得到有效抑制,工程实际减少常态回淤量约17.4%;2)完善工程实施后,南导堤涨潮越堤水沙基本阻断,北槽中下段含沙量也有所减小,北槽潮流方向更加归顺,常态回淤量降幅约5.6%;3)工程达到了预期的航道减淤目标,工程治理方案合理,航道减淤效果符合预期。

To reduce the normal siltation amount of the Yangtze Estuary deep-water channel,the jetty heightening project in the southern groin field of the siltation reduction project of the Yangtze Estuary deep-water channel is carried out in two stages:the previous project and the perfect project.Based on the measured data before and after the siltation reduction project in the deep-water channel,the changes of water and sediment flux,sediment concentration,flow field,surrounding river regime and siltation reduction in the channel are comprehensively analyzed.The results show that:1)after the previous project of the siltation reduction project,the water and sediment flow over the southern groin field decreased significantly,the sediment concentration in the north channel decreased significantly,the lateral water and sediment transport in the south side of the channel was effectively suppressed,and the actual normal siltation amount decreased by about 17.4%.2)After the perfect project of the siltation reduction project,the water and sediment flow over the southern groin field are basically blocked,the sediment concentration in the middle and lower parts of the north channel also decreases,the tidal current direction of the north channel becomes more smoother,and the normal siltation amount decreases by about 5.6%.3)The project achieves the expected channel siltation reduction target,the engineering treatment scheme is reasonable,and the channel siltation reduction effect meets the expectation.