秦岭北麓沣河流域地下水-地表水化学特征及转化关系  

Chemical Characteristics and Transformation Relationship of Groundwater and Surface Water in Fenghe River Basin at the Northern Foot of Qinling Mountains,China

作　　者：吴志豪 高燕燕 温芮 钱会[1,2,3] 洪敏 WU Zhi-hao;GAO Yan-yan;WEN Rui;QIAN Hui;HONG Min(School of Water and Environment,Chang'an University,Xi'an 710054,Shaanxi,China;Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education,Chang'an University,Xi'an 710054,Shaanxi,China;Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources,Chang'an University,Xi'an 710054,Shaanxi,China;Shaanxi Satellite Application Technology Center for Natural Resources,Xi'an 710154,Shaanxi,China)

机构地区：[1]长安大学水利与环境学院,陕西西安710054 [2]长安大学旱区地下水水文与生态效应教育部重点实验室,陕西西安710054 [3]长安大学水利部旱区生态水文与水安全重点实验室,陕西西安710054 [4]自然资源陕西省卫星技术应用中心,陕西西安710154

出　　处：《地球科学与环境学报》2024年第3期334-350,共17页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(42341102,42102288);陕西林业科技创新重点专项项目(SXLK2023-02-1);中央高校基本科研业务费专项资金项目(300102263401)。

摘　　要：秦岭北麓沣河是“长安八水”之一,对其水环境现状、影响因素及地表水-地下水转化关系进行深入研究是河流生态修复的关键。根据2022年7月在沣河流域采集的62个地下水样和17个地表水样的分析结果,采用数理统计法、Piper图、Gibbs图、离子比法和氢氧同位素分析了地下水和地表水化学特征及其影响因素,探究了地下水和地表水的转化关系。结果表明:①研究区地下水为弱碱性,约有50%为极硬水、25%为硬水,溶解性总固体(TDS)较大,最大值高达1916 mg·L^(-1),NO_(3)^(-)浓度较高;地表水为弱碱性,为软水或微硬水,溶解性总固体较小,有机物含量较高;地表水和地下水阳离子均以Ca^(2+)为主,阴离子均以HCO_(3)^(-)为主,地表水基本是HCO_(3)-Ca型水;地下水化学类型主要有HCO_(3)-Ca、HCO_(3)·SO_(4)-Ca、HCO_(3)-Ca·Mg和HCO_(3)·SO_(4)-Ca·Mg型,分别占比24.19%、24.19%、16.13%和9.68%,且水化学类型空间变化较大。②研究区水化学特征主要受到岩石风化作用的控制,蒸发浓缩和大气降水也有一定影响;水中Na^(+)除岩盐溶解外,还有硅酸盐风化的影响,Ca^(2+)、Mg^(2+)和HCO_(3)^(-)主要来源于方解石、白云石等碳酸盐的风化溶解;地下水中阳离子交替吸附作用普遍发生,对Ca^(2+)和Na^(+)浓度影响较大;人类活动增加了部分地下水中SO_(4)^(2-)、NO_(3)^(-)和Cl^(-)浓度,相比之下地表水受到人类活动的影响较小。③研究区洪积扇扇顶-扇中主要是地表水补给地下水,补给比例为46.62%;洪积扇前缘主要是地下水补给地表水,补给比例为13.62%;下游平原主要是地表水补给地下水,补给比例为38.39%。The Fenghe River is one of the“Eight Waters of Chang'an”,and in-depth research on the status quo of its water environment,influencing factors,and the relationship between surface water and groundwater transformation is the key to the ecological restoration of the river.Based on 62 groundwater samples and 17 surface water samples collected in Fenghe River Basin in July 2022,the chemical characteristics and influencing factors of groundwater and surface water were analyzed by mathematical statistics,Piper diagram,Gibbs diagram,ion ratio method and hydrogen and oxygen isotopes,and the transformation relationship between groundwater and surface water was explored.The results show that①the groundwater in the study area is weakly alkaline,about 50%is extremely hard water,25%is hard water,and the total dissolved solids(TDS)is large,the maximum value is as high as 1916 mg·L^(-1),and NO_(3)^(-) concentration is high;surface water is weakly alkaline,soft or slightly hard water,with less TDS and more organic matter;the cations of surface water and groundwater are mainly Ca^(2+),the anions are mainly HCO_(3)^(-),and the surface water is basically HCO_(3)-Ca water;the main chemical types of groundwater are HCO_(3)^(-)Ca,HCO_(3)·SO_(4)-Ca,HCO_(3)^(-)Ca·Mg and HCO_(3)·SO_(4)-Ca·Mg types accounted for 24.19%,24.19%,16.13% and 9.68%,respectively,and the spatial variation of water chemistry type is large.②The water chemical characteristics of the study area are mainly controlled by rock weathering,and evaporation concentration and atmospheric precipitation are also affected;in addition to the dissolution of rock salt,Na^(+) in water should also be affected by silicate weathering,and Ca^(2+),Mg^(2+) and HCO_(3)^(-) mainly come from the weathering and dissolution of carbonates such as calcite and dolomite;the alternating adsorption of cations in groundwater is common,which has a great impact on Ca^(2+)and Na^(+)concentrations;human activities have increased the concentrations of SO_(4)^(2-),NO_(3)^(-) and Cl^(-) in some

关 键 词：水化学 影响因素 转化关系 地下水-地表水 离子比 补给比例 氢氧同位素 渭河流域 

分 类 号：P64[天文地球—地质矿产勘探]