万家寨水库排沙效果及影响因素分析

Analysis of Sediment Discharge Effect and Influencing Factors of Wanjiazhai Reservoir

降水冲刷是恢复水库库容的有效手段。2011年以来万家寨水库在排沙期多次开展降水冲刷运用,取得了较好的排沙效果。基于实测资料,分析了2011年以来万家寨水库排沙效果及其影响因素。结果表明:2011—2021年(不含2016年)万家寨水库累计排沙7.173亿t;排沙主要集中在排沙期;2018—2020年来水较丰,水库降水冲刷历时长,3 a累计排沙4.840亿t;水库排沙影响因素众多,长历时大流量洪水过程有利于水库排沙;运用水位降低时,蓄水量减小,沿程冲刷距离长,壅水输沙距离缩短,有利于提高水库的排沙效果。通过回归分析,建立了不同水位下出库输沙率与主要影响因素的关系。

Lowering water level and scouring is an effective measure to restore reservoir capacity.Since 2011,Wanjiazhai Reservoir has used this measure for many times in the period of sediment discharge and achieved a good effect of sediment discharge.Based on the measured hydrological data,this paper analyzed the effectiveness and influencing factors of lowering water level and scouring of the Wanjiazhai Reser-voir since 2011.The results show that a total of 717.3 million tons of sediment has been discharged by the reservoir from 2011 to 2021(ex-cluding 2016).The sediment discharge is mainly concentrated during the sediment discharge period.From 2018 to 2020 water is abundant,the time of lowering the water level and scouring of the reservoir is long and a total of 484 million tons of sediment is discharged during the three years.There are many factors affecting sediment discharge in reservoirs,and long-term large inflows are beneficial to reservoir sediment discharge.When the operational water level is decreased,the storage is decreased,the scouring distance along the channel is longer,and the backwater sand transport distance shortened,which is conducive to improving the sediment discharge effect of the reservoir.Through regres-sion analysis,the relationship between the sediment transport rate and the main influencing factors under different water levels is established.