Water quality and interaction between groundwater and surface water impacted by agricultural activities in an oasis-desert region

•Water quality and groundwater-surface water interaction in the oasis-desert region of Tarim Basin were examined.•Stable isotopes and EC of phreatic water in non-irrigation areas were much greater than those in irrigation areas.•Phreatic water in the study area is generally not suitable for agricultural irrigation at present.•Large-scale land reclamation and irrigation in arid region have caused a strong interaction between phreatic water and surface water.