三峡坝址来水变化及水利工程对其影响分析

气候变化和人类活动导致长江流域水资源年际、年内均发生变化。利用不同趋势分析和突变分析法,选取1890—2020年三峡坝址来水资料分析来水变化趋势以及溪洛渡、向家坝、三峡水库建库前后三峡坝址处年均、消落期、汛期、蓄水期来水变化。结果表明:三峡坝址在年均、汛期、蓄水期来水减小趋势显著,消落期减小趋势不显著,三峡坝址来水变化趋势突变时间在1960年左右。溪洛渡和向家坝水库在枯水期向下游补水导致三峡坝址来水增加,造成溪洛渡、向家坝建库后三峡消落期来水比历史反向增大,说明巨型水库对长江上游及金沙江流域水资源时空分布影响较大。

Impact of Water Conservancy Projects on Variation of Water Inflow at the Three Gorges Dam Site

Climate change and human activities have led to changes in the water resources of the Yangtze River Basin in both annual and monthly scales. By using different trend analysis and abrupt change analysis methods, the water inflow trend at the Three Gorges dam site was examined based on inflow data from 1890 to 2020. The changes of water inflow in annual average scale, in water level drawdown period, in flood season, and in impoundment period at the Three Gorges dam site before and after the construction of the Xiluodu, Xiangjiaba, and Three Gorges Reservoir projects were also scrutinized. Results revealed that the inflow at the Three Gorges dam site showed a significant decreasing trend in annual average, in flood season, and in impoundment period, but an insignificant decreasing trend in the water level drawdown period. The inflow trend changed abruptly around 1960. The Xiluodu-Xiangjiaba Reservoir’s water supply downstream during dry season led to an increase in the inflow of the Three Gorges dam site, implying that giant reservoirs have a great impact on the temporal and spatial distribution of water resources in the upper reaches of the Yangtze River and the Jinsha River.