三峡水库入库水沙变化规律及驱动因素分析

Variations and driving factors of water flow and sediment transport in the Three Gorges Reservoir

基于流域内1956-2018年长序列实测径流泥沙资料,利用M-K突变检验、双累积曲线等方法分析了三峡水库入库水沙不同时段变化规律,确定了减沙的主要因素,进而采用产沙函数模型结合灰色关联分析量化计算各因素对减沙的贡献比并对比例变化进行了简单预测。研究结果表明:径流量无明显的趋势性变化,年际间输沙量呈减小的趋势,年内泥沙输移量的减少主要集中于汛期。1993年和2003年分别为减沙趋势显著增强的起始年份和泥沙序列减沙速率持续加快的突变点。1993年以来,水库拦沙的减沙贡献量超过50%。今后较长时期水库拦沙仍将是主导性减沙因素,近期水保工程和降水的减沙比重分别有所上升和下降,预计之后将分别有所下降和维持在较低水平。

Based on the runoff and sediment data during 1956-2018 in the basin,the variation law of inflow water and sediment in different periods of the Three Gorges Reservoir are analyzed by using M-K mutation test model and double accumulation curve,and the main factors of sediment reduction are determined.The contribution ratio of each factor to sediment reduction is calculated by sediment yield function model combined with grey correlation analysis,and the change of proportion is simply predicted,Results show that there is no obvious trend change in runoff,the annual inter sediment transport is decreasing,and the decrease of sediment transport in the annual distribution is concentrated in the flood season.In 1993 and 2003,the sediment reduction trend increas significantly and the sediment reduction rate of sediment sequence continued to accelerate.Since 1993,the sediment reduction contribution of reservoir sediment retention has accounted for more than 50%,and it is expected that it will still be the dominant sediment reduction factor for a long time in the future.Recently,the sediment reduction proportions of soil and water conservation project and precipitation are increase and decrease respectively.