长江河口水下三角洲冲淤分析

The Yangtzerier delta under water sediment analysis

长江河口泥沙主要来自于长江流域,三峡水库蓄水以后,流域来沙量明显减少,必会导致长江河口的冲淤发生变化,对河口稳定有较大的影响。长江河口水下三角洲40多年的实测资料分析表明,当大通站的年均径流量为26452 m^(3)/s,年均输沙量为3.66亿t时,长江河口水下三角洲等深线变化不大。分别运用资料分析及一维数模预测了三峡水库运行20年大通站的水沙情况,结果表明三峡水库蓄水运用前20年大通站的年均径流量基本不变,而年均输沙量约为2.17亿t,较三峡蓄水前减少48.5%。因此长江河口水下三角洲等深线将退蚀。

the sediment of the Yangtze estuary primarily comes from the Yangtze drainage area.After the operation of Three Gorges reservoir,the sediment discharge of the Yangtze drainage has greatly decreases,leading to the change in the Yangtze estuary,it has tremendous influence on the estuary stability.The analytical result which bases on more than 40 years the field data indicates that,when the annual runoff is 26452 m^(3)/s and the annual sediment discharge is 3.66×10^(8)tons at Datong station,the isobaths in the Yangtze Estuary subaqueous delta remain unchangeable.The paper will separately adopt the material analysis and one dimensional mathematical model,which are used to forecast the runoff and sediment discharge at Datong station after the Three Gorges reservoir running 20 years.the results indicate,the annual runoff is invariable basically,but the annual sediment discharge at Datong station is about 2.17×108 tons,reduces by 48.5%compared with before the operation of Three Gorges reservoir,so the Yangtze Estuary subaqueous delta will be eroded.