基于氢氧稳定同位素示踪的秦岭森林小流域径流水源解析  

Water Source Analysis of Runoff in Qinling Forest Small Watershed,China Based on H-O Stable Isotope Tracing

作　　者：马天文 徐国策[1] 赵超志 毛金沙 徐明珠[1] 熊海晶 魏全 方康 万顺 MA Tian-wen;XU Guo-ce;ZHAO Chao-zhi;MAO Jin-sha;XU Ming-zhu;XIONG Hai-jing;WEI Quan;FANG Kang;WAN Shun(State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China,Xi an University of Technology,Xi an 710048,Shaanxi,China;Shaanxi Transportation Holding Group Co.,Ltd.,Xi an 710065,Shaanxi,China)

机构地区：[1]西安理工大学西北旱区生态水利国家重点实验室,陕西西安710048 [2]陕西交通控股集团有限公司,陕西西安710065

出　　处：《地球科学与环境学报》2022年第3期545-557,共13页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(51979219);陕西省交通运输厅科技项目(2015-11K)。

摘　　要：江河源头区和水源涵养区的径流水源解析对深入理解流域水资源演变规律和水资源安全具有重要意义。选择汉江支流丹江的二级支流闵家河森林小流域,基于两次降雨事件下不同水体的氢氧稳定同位素采集分析,利用端元混合模型计算了两次典型降雨事件下事件水(降雨)和事件前水(流域前期储水)对河道径流的贡献比例及其动态变化特征。结果表明:小雨和暴雨事件下,河道径流的δD值分别为-64.23‰~-53.95‰和-81.35‰~-67.68‰,电导率分别为328~413和301~426μS·cm^(-1),总体上先下降后上升,洪峰滞后最大降雨强度的时间分别为22和16 h;小雨和暴雨事件下事件前水的贡献比例为93.5%和77.1%,洪峰时事件前水的贡献比例均高于事件水;小雨和暴雨事件时间来源划分的平均不确定性在95%置信区间分别为34.4%和28.9%,说明划分结果总体较为可靠;流域对降雨的拦蓄作用显著,小雨和暴雨事件下事件水的贡献量转化为径流深后分别为0.20和3.04 mm,仅分别占对应降雨量的1.7%和5.9%。降雨前包气带湿润程度和降雨强度对降雨径流的形成过程具有重要影响。包气带越湿润,降雨强度越大,事件水对河道径流的贡献比例越高。因此,流域径流水源变化定量分析可以为变化环境下秦岭水源涵养、水源地保护和径流变化归因分析提供科学指导。The analysis of runoff water sources in the river headwater and water conservation areas is of great significance for understanding the evolution of water resources in the basin and the safety of water resources in China.Minjiahe forest watershed of Dan River,which is a branch of Han River,was selected as the study area.Based on H-O stable isotope collection and analysis of different water bodies under rainfall,the contribution ratio and dynamic change characteristics of event water(rainfall)and pre-event water(pre-watershed water storage)to river runoff under two typical rainfall events were carried out by end-member mixing analysis model.The results show that theδD values of runoff under light rain and heavy rain events are-64.23‰--53.95‰and-81.35‰--67.68‰,respectively;EC values are 328-413 and 301-426μS·cm^(-1),respectively.In general,the trend first decreases and then increases,and the time lag behind the maximum rainfall intensity of the flood peak is 22 and 16 h,respectively.Contribution ratios of pre-event water under light rain and heavy rain events are 93.5%and 77.1%,respectively.At the flood peak,the contribution ratio of pre-event water is higher than that of event water.The average uncertainties of the water source classification results under light rain and heavy rain events in the 95%confidence interval are 34.4%and 28.9%,indicating that the classification results are generally reliable.The watershed has a significant effect on the interception of rainfall.The contributions of event water under light rain and heavy rain events convert into runoff depths of 0.20 and 3.04 mm,respectively,which only account for 1.7%and 5.9%of the corresponding rainfall.The wetness degree and rainfall intensity of the vadose zone before rainfall have important influence on the formation process of rainfall-runoff.The wetter the vadose zone,the greater the rainfall intensity,and the higher the contribution ratio of event water to river runoff.Therefore,the quantitative analysis of water source in watershed run

关 键 词：水源解析 氢氧稳定同位素 电导率 端元混合模型 森林流域 径流分割 产流机制 秦岭 

分 类 号：P343.1[天文地球—水文科学] S715[天文地球—地球物理学]