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近年来,受人类活动和气候变化等因素的影响,长江流域的来水来沙特性发生了一些变化。以大通水文站为例,选取1986~2012年的实测水沙资料,分析了水沙关系特性及悬沙中值粒径、悬沙颗粒组成变化规律。结果表明,月均流量与输沙率变化过程具有良好的一致性,且存在着输沙率峰值超前或滞后于流量峰值的现象;三峡水库蓄水后,大通水文站的水文泥沙特性发生了明显变化,洪季泥沙中值粒径大于枯季,汛初流量增大阶段泥沙粗于汛末流量减小阶段,多年平均中值粒径基本不变,但泥沙有逐年变粗的趋势。
In recent years, due to the influence of human activities and climate change, some changes have taken place in the characteristics of incoming and outgoing water and sediment in the Yangtze River Basin. Taking Datong Hydrological Station as an example, the measured water and sediment data from 1986 to 2012 were selected to analyze the relationship between water and sediment characteristics and the variation of suspended sediment median particle size and suspended sediment particle composition. The results show that there is a good consistency between monthly average flow rate and sediment transport rate, and there is a phenomenon that the peak value of sediment discharge rate leads or lags the peak flow rate. After the Three Gorges Reservoir is charged, the hydrological and sediment characteristics of Datong Hydrologic Station occur In the flood season, the median diameter of sediment is larger than that in dry season, and the sediment is thicker than the end of flood season at the beginning of flood season. The average median diameter of sediment is basically unchanged in many years, trend.