1969-2018年黄河实测径流与天然径流的变化

Variation of Observed and Natural Runoff of Yellow River from 1969 to 2018

[目的]分析黄河实测径流与天然径流的变化规律,为探究人类活动对径流的影响提供依据。[方法]基于1969—2018年黄河干流8个水文站的天然径流和实测径流数据,使用Mann-Kendall趋势检验与突变检验法,对比分析近50 a黄河干流实测径流和天然径流的变化规律。并结合近15 a各分区耗水数据探讨人类活动对于径流的影响。[结果](1)1969—2018年黄河上中下游实测径流整体呈降低趋势,兰州、花园口、利津3个代表站多年平均降低速率分别为5.10×10^7,3.55×10^8,4.13×10^8 m^3/a。(2)近50 a天然径流和实测径流趋势突变主要集中在1986和1990两个年份,结合前人研究和重要水事分析,1986年突变可能与1984年以来一系列水土保持措施实施以及1986年龙羊峡水库修建有关;而造成1990年径流突变的原因可能是80—90年代黄河流域用水量激增和流域下垫面改变。(3)天然径流与实测径流的差值从上游至下游水文站断面逐渐增大,这主要与近15 a平均耗水量也沿程增大相一致;另外多年平均实测径流在利津站仅占天然径流的42%。耗水量最大的两个分区为花园口以下和兰州—头道拐段,分别达到了1.06×10^10和1.04×10^10m^3。[结论]人类活动中的各项耗水(尤其是农田灌溉)是造成兰州站以下地区天然径流与实测径流差值大的主要原因,因此,应进一步推进黄河流域节水农业的发展,合理分配各项耗水量。

[Objective]The variation of the observed runoff and natural runoff of the Yellow River was analyzed to explore the impact of human activities on runoff in the study area.[Methods]Based on the natural runoff and observed runoff of eight hydrological stations in the main stream of the Yellow River from 1969 to 2018,the variation of the observed natural runoff in the last 50 years was analyzed using a Mann-Kendall trend test and mutant test.In addition,the impact of human activities on runoff was considered based on the water consumption data of each region in the last 15 years.[Results]①The observed runoff in the upper,middle,and lower reaches of the Yellow River all decreased from 1969 to 2018.The average annual reduction rates at the Lanzhou,Huayuankou,and Lijin stations were 51,355,and 413 million m^3/a,respectively.②In the last 50 years,the greatest alteration of natural runoff and observed runoff occurred during 1986 and 1990.Combined with previous studies and important water events of the Yellow River,the runoff alteration in 1986 may have been related to the implementation of soil and water conservation measures since 1984 as well as the construction of Longyangxia Reservoir in 1986.The runoff alteration in 1990 may have been due to the surge of water consumption in the 1980s and 1990s in addition to the underlying surface water variation of the basin.③The difference between the natural and observed runoff gradually increased from the upper reach to the lower reach,which was generally consistent with the increased average water consumption over the past 15 years.In addition,the annual average observed runoff only accounted for 42%of natural runoff at Lijin Station.The two regions with the highest water consumption were the lower part of Huayuankou and the area between Lanzhou and Toudaoguai,reaching 1.06×10^10 m^3 and 1.04×10^10 m^3,respectively.[Conclusion]The main reason for the large difference between the natural and observed runoff in the area below Lanzhou station was the water consumption associated with human activities,especially for farmland irrigation.Therefore,it is necessary to promote the development of water-saving agriculture in the Yellow River basin and to reasonably allocate water consumption.