窟野河流域水沙变化及其驱动因素

Runoff and Sediment Load Variation and Driving Factors in the Kuye River Basin

[目的]探究窟野河流域径流和输沙变化特征,量化气候变化及人类活动对流域水沙变化的贡献,以期为窟野河流域水资源合理利用和水土保持措施的优化配置提供科学依据。[方法]基于窟野河流域新庙、王道恒塔、神木和温家川水文站1960—2020年径流、输沙及降雨资料,采用线性趋势法、Mann-Kendall趋势检验和Pettitt突变检验法分析了流域径流输沙时空变化特征,结合双累积曲线法定量分析了不同时期气候变化与人类活动对河流水沙变化的贡献。[结果]窟野河流域1960—2020年径流输沙均呈现极显著减少趋势(p<0.01),新庙、王道恒塔、神木和温家川4站径流量减少速率分别为0.024亿m^(3)/a,0.034亿m^(3)/a,0.081亿m^(3)/a,0.106亿m^(3)/a,输沙量减少速率分别为43.8万t/a,69.3万t/a,160.3万t/a,272.1万t/a,且各水文站年径流量和输沙量均在1979年、1996年发生突变,由此可将径流输沙序列划分为基准期(1960—1979年,P 1期)和变化期(1980—1996年,P 2期;1997—2020年,P 3期)。研究时段内不同子流域多年平均径流深和输沙模数均呈减小趋势,但在空间上存在差异。[结论]流域不断增强的人类活动(水利水保措施与煤矿开采等)是窟野河流域水沙变化的主导因素,相较基准期,各水文站径流输沙量在P 2期、P 3期均减少,且P 3期减少幅度更剧烈,不同水文站在P 2和P 3期内,人类活动对径流输沙减少的贡献高于降雨变化。

[Objective]The aims of this study are to investigate the spatial and temporal changes of runoff and sediment load in the Kuye River Basin,to quantify the contribution of climate change and human activities to variation of runoff and sediment load,and to provide scientific basis for the rational use of water resources and the optimal allocation of soil and water conservation measures in the Kuye River Basin.[Methods]Based on the runoff,sediment load and rainfall data of Xinmiao,Wangdaohengta,Shenmu and Wenjiachuan hydrological stations in Kuye River Basin from 1960 to 2020,the spatial and temporal variation characteristics of runoff and sediment load were analyzed by the linear trend method,Mann-Kendall trend test and Pettitt mutation test,and the double mass curve was used to quantitatively analyze the contribution rate of climate change and human activities to runoff and sediment load variation in different periods.[Results]Annual runoff and sediment load in the Kuye River Basin showed a significant decreasing trend from 1960 to 2020(p<0.01).The runoff reduction rates of Xinmiao,Wangdaohengta,Shenmu and Wenjiachuan hydrological stations were 2.4 million m^(3)/a,3.4 million m^(3)/a,8.1 million m^(3)/a,10.6 million m^(3)/a,the reduction rates of sediment load were 0.438 million t/a,0.693 million t/a,1.603 million t/a and 2.721 million t/a,respectively.The annual runoff and sediment load of each hydrological station changed abruptly both in 1979 and 1996,so the runoff and sediment load sequences could be divided into the reference period(1960—1979,P 1)and the change period(1980—1996,P 2;1997—2020,P 3).During the study period,the average annual runoff depth and sediment load modulus of different sub-basins showed a decreasing trend,but there were differences in space.[Conclusion]The increasing human activities(water conservancy and soil conservation measures,coal mining,etc.)are the dominant factors on variation of runoff and sediment load in the Kuye River Basin.Compared with the base period,the runoff and sediment load of each hydrological station decreased in both P 2 and P 3 periods,and reduction was more intense in P 3 period.In the P 2 and P 3 periods,the contribution of human activities to the reduction of runoff sediment transport was higher than that of rainfall changes.