三峡水库首次蓄水对泥沙输移特性的影响

以2003年三峡库区及坝下游水文站水沙整编资料为基础,分析了水库上游来水来沙情况,并与2002年比较,讨论了不同阶段水库悬移质泥沙输移的不同特征。结果表明,在水库135m蓄水以前,库区河道微冲;蓄水期间排沙比最小,仅10%左右;两次蓄水过程后排沙比约15%左右;全年排沙比约30～40%,其中约85%左右的泥沙输移是在两次洪水过程中完成的,两次洪水过程排沙比近50%。来水来沙量大时,泥沙主要淤积在万县—大坝区间,来水来沙量小时,主要淤积在清溪场—万县区间。水库的输沙特性主要受库尾地形、水面比降、流量、含沙量等因素的影响。

The impact of initial water impoundment on sediment transport of Three Gorges Reservoir

Based on the flow and sediment compilation data of Three Gorges Reservoir(TGR) areas,the properties of the incoming water and sediment and the different characteristics of suspended sediment movement are analyzed for TGR at different stage.The results show that before the initial water impoundment to the water level of 135m,the incoming sediment load is small and the river channel in the reservoir area is under slight scour.During the period of the initial water impoundment,the sediment delivery ratio is at the least,only about 10%;after twice the water impoundment processes,the ratio is increased to about 15% and the ratio for the whole year ranges from 30% to 40%,in which nearly 85% of the sediment has been delivered during two high flood process when the ratio is nearly to 50%.During periods of large inflows and sediment,the sediment mainly deposits on the section from Wanxian to the dam site.While during periods of small inflows and sediment,the sediment mainly deposits on section from Qingxichang to Wanxian.The main factors that influence the sediment transport are the terrain at reservoir head,the water surface slope,the magnitude of discharges and sediment concentrations.