黄河中游区间干支流径流变化特征与归因分析

Analysis on runoff regime in middle Yellow River and its driving factors

为探究黄河中游径流时空变化特征及其驱动因素,本文采用Spearman秩相关系数、水文情势突变指标及双累积曲线法对中游头道拐-花园口区间干流4个水文站及11条典型支流1957—2018年实测降雨、径流数据进行统计分析。结果表明:黄河中游干流站年径流量呈显著减少趋势(显著性水平0.001),各站年径流发生两次突变,且都出现在1969年与1987年前后;区间11条支流多年径流深自1970s后显著减少,头道拐–龙门区间径流占整个中游区间径流的比例由2000年前的31%减至之后的23.5%,龙门断面以下区间占比则明显上升;人类活动对头道拐–龙门与龙门–潼关区间多年平均径流变化贡献率分别为62.68%和79.85%,坝库工程、引水灌溉及梯田林草等水利水保工程措施是黄河中游径流锐减的主要驱动力。

This paper presents a systematic analysis on spatiotemporal variations in the runoff in the middle Yellow River and its driving forces, using the methods of Spearman rank correlation test, regime shift index, and double mass curve, based on the 1957-2018 hydrological series at four mainstream stations and eleven typical tributaries in Toudaoguai-Huayuankou reach. The results reveal a significant decreasing trend at the significance level of 0.001 in the annual runoff in the middle Yellow River mainstream and two abrupt changes in its hydrological regime in 1969 and 1987. Since the 1970 s, the runoff depth in these tributaries has reduced with time significantly;the runoff proportion of ToudaoguaiLongmen reach to the entire middle Yellow River has decreased from 31% to 23.5% around the year 2000, while the proportions of all the reaches below Longmen have increased obviously. The average contribution rate of human activities to runoff variations was 62.68% in Toudaoguai-Longmen reach and 79.85% in Longmen-Tongguan reach. The major driving forces of runoff reduction are the operation of water conservancy projects and the implementation of soil and water conservation measures, such as reservoirs, check dams, irrigation water diversion works, and terraces.