Identifying the Binary Mixing of Groundwater——an Example as Groundwater in the Shallow Aquifer of the Guanzhong Basin

Environmental tracers of CFCs were used to identify the binary mixing of groundwater from the shallow aquifer in the Guanzhong Basin.Theoretical analyses indicate that the CFC ratios keep conservative no matter whether mixing processes have occurred.The ratio ages and CFC concentration ages can be used to identify and estimate the binary mixing in groundwater.The CFC concentrations in groundwater from the piedmont recharge area was high,whereas decreased to the Wei river valley,indicating that the shallow groundwater flow was predominated in lateral pattern and the young portion recharged in the piedmont area mixed with old groundwater along its flowing path.Over 50% of young fraction in the mixture of groundwater was observed,which indicates that the aquifer system in the Guangzhong basin was mainly recharged by modern recharge.