Evaluation of surface water–groundwater interaction using environmental isotopes (D, 18O and 222Rn) in Chongli Area, China

In order to understand the interaction between surface water and groundwater in Qingshuihe Basin of Chongli Area, the environmental isotopic D, 18O and 222Rn in surface water and groundwater have been analysis, the study results show that: the calculation results based on the D and 18O, the surface water in middle stream of Donggou River has been recharged by groundwater and river water upstream, the percentage of groundwater recharge is 56%; the calculation results based on the 222Rn, the average seepage rate of surface water is 27.8 m3/d/m in the upstream section, and the average recharge rate of groundwater is 17.6 m3/d/m. It is concluded that, the groundwater and surface water interaction is the main characteristics and processes of water cycle in Qingshuihe Basin, and groundwater recharge is the main sources of surface water in draught seasons.