In addition, three groundwater samples were collected every 2 months at each point. Chemical components, including HCO3, SO42, Cl, Ca2+, Mg2+, Na+ and K+ , were measured at the Institute of Geography Sciences and Natural Resources Q3 Research, Chinese Academy of Sciences. Levels of SO4 2 and Cl were analysed by ion chromatography, and HCO3
anions were analysed by titration (001 N H2SO4). Cations were analysed by inductively coupled plasma. TDS represent the sum of the cations and anions in the water.