黄河中游昕水河流域水沙变化及归因研究

Study on the Variation and Attribution of Runoff and Sediment in Xinshui River Watershed of Middle Yellow River

为了探讨人类活动和气候变化对黄河流域水沙情势的影响,选取黄河中游典型流域——昕水河流域为研究区域,分析流域1958—2015年水文气象年际变化规律,采用Mann-Kendall检验法和Pettitt检验法对流域径流量、输沙量及含沙量进行趋势分析和突变检验,并分别利用双累积曲线法、回归分析法和弹性系数法对水沙变化的归因进行了对比评价。结果表明:(1)流域多年平均径流量、输沙量和含沙量分别为32.0 mm,1289.1 t/km^(2)和33.7 kg/m^(3),年径流量、输沙量和含沙量均呈现显著下降趋势,且其突变时间均出现在1980年附近;(2)在1958—1980年和1981—2002年期间,流域年水沙关系表现出较好的线性关系,但是2003—2015年期间流域年径流—输沙关系的相关性明显减弱,水沙关系难以用确定的回归方程来表征,其主要原因为流域内水土保持工程措施的实施特别是淤地坝的建设,削弱了流域的水沙关系;(3)双累积曲线法、回归分析法和弹性系数法的计算结果较为接近,人类活动是引起昕水河流域水沙变化的主要驱动因素,传统的经验统计法确实有一定的可靠性和适用性。研究成果可为黄河流域生态恢复及水沙调控提供科学依据。

In order to explore the effects of human activities and climate changes on the runoff and sediment yield in the Yellow River,a typical watershed in the middle reaches of the Yellow River——Xinshui River watershed,was selected as the research area to analyze the annual variation of hydrometeorological factors from 1958 to 2015.The Mann-Kendall test and Pettitt test were used to analyze the trend and mutation of runoff,sediment discharge and sediment concentration.In addition,double cumulative curve method,regression analysis method and elastic coefficient method were used to evaluate the attribution of runoff and sediment yield.Results show that:(1)The annual average runoff,sediment discharge and sediment concentration were 32.0 mm,1289.1 t/km^(2) and 33.7 kg/m^(3),respectively.They all exhibited a significant decreasing trend on the annual scale.The results of mutation test showed that the abrupt change in annual runoff,sediment discharge and sediment concentration all occurred in 1980.(2)Before 2002,the relationship between annual runoff and sediment yield showed a good linear relationship.However,the correlation between annual runoff and sediment yield was significantly weakened during 2003—2015,which was difficult to be represented by a definite regression equation.The main reason was that the implementation of soil and water conservation engineering measures,especially the construction of check-dam,weakened the runoff-sediment relationship.(3)The results of double cumulative curve method,regression analysis method and elastic coefficient method were relatively close.Human activities were the main driving factors of runoff and sediment variations in the Xinshui River watershed.The traditional empirical statistical method does have certain reliability and applicability.This study can provide scientific basis for ecological restoration and regulation of runoff and sediment in the Yellow River watershed.