在对渭河流域407组地下水的水化学数据及139组含水层岩土样数据分析的基础上，运用图解法、数理统计法、Gibbs半对数法及PHREEQC模拟等方法对渭河流域地下水的水化学特征及形成机制进行了研究，取得了一些新的认识。根据地下水系统划分原则，将整个渭河流域的地下水系统划分为5个二级地下水系统：陇西黄土高原子系统、陇东黄土高原子系统、陕北黄土高原子系统、关中盆地子系统以及秦岭北麓子系统。渭河流域水化学类型主要是以HCO3-Ca、HCO3-Na为主，北部和中部还分布有HCO3.SO4-Na、HCO3.SO4.Cl-Na、SO4.Cl.HCO3-Na及Cl.SO4-Na型水，大部分地区地下水中的TDS为小于1g/L的淡水。地下水化学成分的形成主要受含水层矿物的溶解/沉淀、蒸发浓缩及阳离子交换作用的影响。

Based on analysing 407 hydro-chemical data and 139 aquifer rock soil samples date of groundwater fromWei River basin, China, the graphical method, mathematical statistics, Gibbs semi-logarithm diagram and phreeqc simulation method were applied to study the chemical characteristics and formation mechanism of groundwater. According to the principle of division of the groundwater system, the study area can be divided into five secondary groundwater system, namely, Longxi Loess Plateau subsystem, Longdong Loess Plateau subsystem, Shanbei Loess Plateau subsystem, Guanzhong basin Loess Plateau subsystem and Qingling mountains subsystem. The hydro-chemical type of the groundwater in the Wei River basin mainly HCO3-Ca and HCO3-Na, in northern and central there is also distributed HCO3.SO4-Na, HCO3.SO4.Cl-Na, SO4.Cl.HCO3-Na and Cl.SO4-Na type water, most areas groundwater TDS is less than 1g/L of fresh water. the formation of the chemical composition of groundwater were impacted by aquifer mineral dissolution/ precipitation, evaporation concentration and cation exchange.

中国地质调查局地质大调查计划项目 (1212010634700)