三峡水库175m试验性蓄水以来库区河床冲淤特性分析

三峡水库175m试验性蓄水以来入库沙量大幅减少,水库冲淤特性与论证阶段成果存在一定差异。针对这一问题,基于三峡水库蓄水以来库区航道泥沙原型观测资料,系统分析了进出库水沙特性、库区泥沙冲淤变化以及泥沙淤积分布特点。结果表明:1)入库沙量较预期大幅减少;2)淤积主要集中在清溪场以下的常年回水区,淤积量多、淤积强度大的河段主要是常年回水区的开阔与分汊河段;3)泥沙淤积呈现主槽淤平和以一侧淤积为主的不对称淤积的特点。

Analysis on sediment scouring and silting characteristic of Three Gorges Reservoir area since 175 m tiral impoundment

Since the 175 m tiral impoundment of the Three Gorges Reservoir,the amount of sand entering the reservoir has been greatly reduced,and there is a certain difference between the sediment scouring and silting characteristics of the reservoir and the research achievements in the argumentation stage.In response to this problem,based on the prototype observation data of sediment in the channel of the Three Gorges Reservoir since the impoundment of the Three Gorges Reservoir,we systematic analysis the characteristics of inflow-outflow of the water-sediment characteristics,and the sediment scouring and silting situation in the reservoir area and the sediment deposition distribution.The results show that:1)The amount of sand entering the reservoir is significantly reduced than expected.2)The siltation is mainly concentrated in the perennial backwater area below Qingxichang,and the river sections with a large amount of siltation and strong siltation intensity are mainly open and branched river sections in the perennial backwater area.3)Sediment silting presents the characteristics of flat silting in main channel and asymmetric siltation dominated by siltation on one side.