近70年黄河流域水沙情势及其成因分析

深入剖析黄河水沙现状及成因是精准预测黄河未来水沙情势的前提与基础。为此，以黄河干流潼关断面以上4个主要干流水文站及7个主要一级支流把口站1950-2016 年水沙实测资料为基础，采用双累积曲线等多种统计分析方法，系统剖析了黄河流域水沙演变规律及水沙主要源区变化特征，定量评估了不同环境要素对黄河水沙变化影响。结果表明：1）黄河干流兰州、头道拐、龙门及潼关水文站年径流及年输沙量均呈显著减少趋势（P<0.05），其中，年径流减幅17.93%~40.79%，年输沙量减幅均在46.74%以上。受多种因素影响，黄河水沙在20世纪80-90年代发生减少突变；2）兰州-潼关区间年均径流量沿程变化表现为由总体递增状态向递减趋势转变，年均输沙量递增状态虽未转变，但递增幅度平均减小90%以上；3）黄河泥沙主要来源区由头龙区间向龙潼区间发生转移特征明显，龙潼区间水土流失治理有待进一步加强；4）人类活动对黄河中游水沙锐减占据主导作用，平均贡献率达到90%以上。而上游兰州站年均径流量受气候影响较大，贡献率达到66.57%。研究结果可为深刻认识黄河水沙时空现状及成因提供依据，并对未来水土流失治理区位方向确定提供参考。

Analysis on runoff and sediment regimes and its causes of the Yellow River in recent 70 years

Abstract: The future trend of runoff and sediment variation is closely related to the governance of the Yellow River. To accurately predict the future runoff and sediment regimes of the Yellow River, the spatial distribution and its variation process of runoff and sedimentation in the main stream of the Yellow River in various periods were systematically analyzed. Specifically, runoff and sediment loads from 4 main stem hydrometric stations and 7 major primary tributaries above Tongguan section on the Yellow River, during the period from 1950 to 2016, were analyzed by using multiple methods such as double cumulative curves. In this paper, we systematically analyze the characteristics of runoff and sediment yield and changes in its main source areas, and the impact of different environmental factors on runoff and sediment changes in the Yellow River were also discussed. The results showed that, 1) The annual runoff and sediment yield at the Lanzhou, Toudaoguai, Longmen, and Tongguan hydrometric stations of the Yellow River showed a significant decrease (P<0.05) in the past 70 years, the annual runoff decreased by 17.93% to 40.79%, and the annual sediment transport decreased by more than 70%. Under the influence of changes in various environmental factors, the runoff and sediment in the Yellow River have reduced mutations in the 1980s and 1990s. 2) The evolution process of average annual runoff in the Lanzhou-Tongguan section changed from an accumulative increase along the distance from the river source to the trend of an accumulative decrease. Although the average annual sediment accumulation amount did not change, the increase rate decreased by 90% more. 3) It is obvious that the transfer characteristics of the main sediment source area of the Yellow River from the Toudaoguai-Longmen section change to the Longmen-Tongguan section, and we argued that soil erosion control in the Longmen-Tongguan section needs to be further strengthened. At last, human activities play a leading role in the sharp decline in runoff and sediment yield in the middle reaches of the Yellow River, with an average contribution rate of 91.52%. The reduction in average annual runoff of Lanzhou is mainly affected by the climate change, and the contribution rate reaches 66.57%. The results can provide a basis for a deep understanding of the temporal and spatial status and causes of runoff and sediment in the Yellow River, and provide a reference for future direction of soil and water conservation.