| In this study, we analysed both groundwater evolution and hydrogeochemistry mechanisms after collecting and sorting hydrogeology conditions and history information of local groundwater. We also found out the processes of recharge characters of surface water and groundwater, groundwater flow paths, hydrogeology effects on groundwater and groundwater movement by analysing the characteristics of deuterium and oxygen-18 isotopes and hydrochemistry. There are three main parts of this study. Firstly, the distribution of hydrochemistry is in striation evidently and some shallow groundwaters are contaminated by nitrate. Along the flow path, there are several physical and chemistry processes like strong evaporation, dissolution of dolomite and gypsum, deposition of calcite, cation exchange and mixing process. Secondly, Local Meteoric Water Line (LMWL):δ2H=7.05δ180+2.03(‰, R2=0.61) of Liyuan River Basin was reconstructed by weighted average of water isotopes in monthly rainfall records of Zhangye station. Finally, we ran hydrochemistry model (PHREEQC inverse modelling) for groundwater flow paths analysis by setting water isotopes as important bound variable. Results indicated that there are intense interactions between surface water and groundwater. And fine soil plain is possible the area for those interactions, which may make big sense for environmental indication. However, those interactions are not simple mixing or transformation. We knew the flow direction in total clearly, but local small water circulations could exist in some areas.This research effectively showed hydrogeochemistry characteristics of Liyuan River Basin. Groundwater evolution fully reached by PHREEQC inverse modelling at last. This is a very essential supplement for hydrology cycle research of this area. And it is also a good reference for sustainable water use in this place or other arid and semiarid basins.
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