向家坝水电站库区泥沙淤积特性

Sedimentation Characteristics in Reservoir Area of Xiangjiaba Hydropower Station

泥沙淤积是约束水电站调度运行的关键因素之一,为厘清向家坝水电站运行以来的淤积进程,基于实测资料分析库区泥沙淤积特性。结果表明,向家坝水库2013~2018年在正常蓄水位下共淤积泥沙4620×10^(4) m^(3),淤损水库库容0.9%,防洪库容损失0.4%,死库容减少1.0%;淤积主要分布在常年回水区的坝前段、新市至屏山河段,干流泥沙淤积主要集中在天然深泓线附近,干流淤积纵剖面与天然河道纵剖面形态基本一致,支流淤积形态则多为三角洲淤积或锥体淤积。人类活动和滑坡等因素导致库区多处出现较大幅度的点状冲淤。研究成果对金沙江下游梯级水库和三峡水库的联合调度运行有重要意义。

Sedimentation is one of the factors which have to be considered in hydropower station regulation.In order to make out sedimentation process in Xiangjiaba Reservoir since impoundment,the sedimentation characteristics were analyzed based on measured topographical data.A total of 46.2 milllion m^(3) of sediment was trapped in the Xiangjiaba Reservoir from 2013 to 2018,which reduced total storage by 0.9%,decreased flood control storage by 0.4%,and caused 1.0%loss of inactive storage.The sediment was basically deposited in the permanent backwater region and followed natural channel thalweg,with primary deposition zones being near dam region and Xinshi to Pingshan reach.The deposited longitudinal profile in the main stream differed slightly from that of natural condition,while the tributaries showed delta or conical depositions.There existed some discrete local erosion/deposition in the reservoir due to the human activities,landslides and other factors.The results are of significance to the joint operation of cascade reservoirs on the lower reaches of the Jinshajiang River and the Three Gorgers Reservoir.