基于稳定同位素的黄土塬区地下水补给规律研究  

Research on the Groundwater Recharge in Loess Plateau Based on Stable Isotopes

作　　者：赵思远 贾仰文[1] 唐颖栋[2] 牛存稳[1] 龚家国[1] 甘永德 ZHAO Si-yuan;JIA Yang-wen;TANG Ying-dong;NIU Cun-wen;GONG Jia-guo;GAN Yong-de(The State Key Laboratory of Simulations and Regulations of Water Cycles in River Basins,China Institute of Water Resources and Hydropower Research,Beijing 100038,China;Huadong Engineering Corporation Limited,Hangzhou 311122,China;The State Key Laboratory of Three Rivers Source Ecology and Plateau Agriculture and Animal Husbandry Co-sponsored by Qinghai Province and Ministry of Water Resources,Qinghai University,Xining 810016,China)

机构地区：[1]中国水利水电科学研究院流域水循环模拟与调控国家重点实验室,北京100038 [2]中国电建华东勘测设计研究院有限公司,杭州311122 [3]青海大学省部共建三江源生态与高原农牧业国家重点实验室,西宁810016

出　　处：《中国农村水利水电》2022年第8期63-69,77,共8页China Rural Water and Hydropower

基　　金：国家自然科学基金项目(51779272);流域水循环模拟与调控国家重点实验室自主研究课题(SKL2020ZY04);国家高层次人才特殊支持计划(WR0166A012019);国家重点研发计划(SQ2018YFE020049,2018YFC0406406)。

摘　　要：选择典型黄土塬区——长武塬及长武塬边的王东沟小流域作为研究区,对研究区内降水、不同地表植被类型下0~15 m深度范围内的土壤水、井水和泉水样品进行采集,对比分析了各水体氢氧稳定同位素的组成特征,进而对黄土塬区地下水补给方式进行判定。结果发现:降水同位素组成与氘盈余呈现出“先减小后增大的趋势”的季节变化趋势;土壤水样氢氧同位素点样分布于当地大气降水线(Local Meteoric Water Line,LMWL)的右下方,分布较为离散,土壤水入渗过程中活塞流与优先流共同存在;地下水样氢氧同位素点样分布于LMWL和土壤水分蒸发线(Soil Water Euaporation Line,SWEL)之间,其离散程度远小于雨水与土壤水样品;黄土塬区地下水主要接受土壤水通过活塞流和优先流的双重入渗补给。The typical loess plateau area-Changwu Plateau and the Wangdonggou small watershed on the edge of Changwu Plateau is selected as the study area.The precipitation,soil water within the depth range of 0~15 m under different surface vegetation types,well water and spring water are selected.The composition characteristics of the stable isotopes of hydrogen and oxygen in each water body are compared and analyzed,and then the groundwater replenishment method in the loess plateau area is judged.The results show that:①The local atmospheric precipitation line formula(LMWL)isδ^(2)H=7.38δ^(18)O+4.75(R^(2)=0.94,n=60),and the isotopic composition of precipitation and the deuterium surplus shows a seasonal trend of decreasing first and then increasing.②The hydrogen and oxygen isotopes of soil water samples are distributed at the lower right area of LMWL,and the distribution is relatively discrete.The local soil water evaporation line(SWEL)isδ^(2)H=6.15δ^(18)O-13.78(R2=0.79,n=178).The soil water stability isotope changes in the 0~3.5 m soil layer are relatively drastic,while the lower layer changes in a wave-like manner with depth.The distribution of stable isotope soil water in the deep profile has a small abrupt change point,indicating that plug flow and preferential flow co-exist during the process of soil water infiltration.③Combined with an analysis of the hydrogen and oxygen stable isotopic characteristics of rainwater,soil water and groundwater,groundwater in the loess plateau area is mainly recharged by the dual infiltration of soil water through plug flow and preferential flow.

关 键 词：黄土塬区 地下水补给 稳定同位素 活塞流 优先流 

分 类 号：S152.7[农业科学—土壤学]