三峡工程下游宜昌至湖口河段河道演变研究

Study of river channel evolution from Yichang to Hukou at downstream of Three Gorges Project

三峡工程建成运用后,水库下泄泥沙数量大幅减少,长江中下游河道将经历长时期、长河段的冲刷过程。采用一维恒定非均匀悬移质不平衡输沙数学模型,计算了三峡工程下游河道的冲刷状况,对河道冲刷过程、河型变异及河势调整等进行了预测评估。将计算结果与三峡水库2003年蓄水运用后宜昌至湖口河段的实测资料进行对比分析。结果表明,冲刷过程中河道水沙状况发生了一定变化,但原有的基本河型仍保持不变;总体河势稳定,局部河段河势有不同程度的调整。河床冲刷过程和河道演变状况尚在预测范围以内。

After the impoundment of Three Gorges Project,the sediment released from the reservoir is reduced largely and the mid-lower reach of Yangtze River would experience a scouring process in long distance and for a long time.The erosion of the downstream river channel of the Three Gorges Project is calculated by 1D constant non-equilibrium non-uniform suspended sediment model.The erosion process,river type changes and river regime adjustment are predicted and evaluated.The results are compared with the measured data from Yichang to Hukou at downstream after the impoundment of Three Gorges Reservoir in 2003.It shows that the flow and sediment situation changed during erosion process;however,the original river type keeps the same;the river regime is stable,only with adjustments in some local reaches.The erosion process of riverbed and evolution of river channel is within the range of prediction.