Study on hydro-geochemical evolution of groundwater in Yanchi area

Yanchi country is located in the eastern part of Ningxia Hui Autonomous region. Water resources in Yanchi area are scarce, groundwater is the main source of water supply. On the basis of hydrogeology, the mass balance model is used, to model the evolution of hydrogeochemistry of groundwater in Yanchi area. The calculated saturation indices indicated calcite and dolomite are supersaturated with groundwater, while gypsum and fluorite are undersaturated with groundwater along the flow path. The results of mass balance showed along the flow direction, the desorption of Na+ and the dissolution of gypsum are the main reactions in groundwater system. The dissolution/precipitation of calcite, dolomite, halite etc. have different effects on the chemical composition of groundwater in different flow paths.