水电能源科学

为了阐释自然与人类活动对河源区水沙演变的影响，以颍河源流区为例，根据告成水文站1975～2020年水沙实测数据，采用Mann-Kendall检验、累积离均差率法、R/S分析、双累积曲线、累积距平等方法研究其水沙变化趋势与特征。结果表明，源流区年径流表现为不明显下降趋势，年输沙量则呈极显著下降态势，两者的Hurst指数分别为0.596 8、0.860 6,表明其下降趋势在未来几年内还将持续；年水沙系列分别表现为6个、2个明显的变化阶段，两者变化的局部过程不同，但总体趋势大体一致；年际水沙关系演变反映在3个阶段(1975～1983、1984～2002、2003～2020年)双累积曲线线性关系的斜率依次递减，分别在1984、2003年发生明显的转折，可见随着人类活动的加剧，降低了输沙量对径流量的响应程度。

To explain the influence of natural and human activities on the evolution of water and sediment in the headwater region, taking the headwater region of Yinghe River as an example, the trend and characteristics of water and sediment change were studied by Mann-Kendall test, cumulative deviation rate method, R/S analysis, double accumulation curve and cumulative distance equality method based on the measured data of water and sediment from 1975 to 2020 in the hydrology station of Gaocheng. The results were as follows: The annual runoff in the source area showed insignificant downward trend while the annual sediment discharge was very significant downward trend, and this trend would continue in the next few years because Hurst exponent of the two were 0.596 8 and 0.860 6, respectively. The annual water and sediment series showed 6 and 2 distinct change stages, respectively. Local changing processes of the two were different, but the overall trend was the same. The evolution of the inter-annual water-sediment relationship was reflected in the slope of the linear relationship of the double accumulation curve decreasing successively in three stages(1975-1983, 1984-2002, 2004-2020), and obvious turning points occurred in 1984 and 2003, respectively. With the intensification of human activities, the response degree of sediment discharge to runoff is being reduced.