Identifying the factors controlling surface water and groundwater chemical characteristics and irrigation suitability in the Yarkant River Basin, northwest China.

This study investigated the geochemical processes and the suitability for irrigation purposes of surface water and groundwater in the Yarkant River Basin, northwest China. The results showed that the surface water was moderately alkaline and neutral to slightly alkaline in the groundwater. The mean values for most ions in the groundwater were higher than those in the surface water. Geochemical method and hydrogen and oxygen isotope revealed that hydrochemical were mainly affected by dissolved evaporite minerals, ion exchange processes, and anthropogenic activities. Still, the geochemical processes of in surface water and groundwater were different. Additionally, three and four factors were extracted by factor analyses of surface water and groundwater, respectively, which distinguished the hydrochemical from natural origins and anthropogenic activities in more detail. The surface water and some groundwater in the south of the study area were suitable for irrigation processes. However, many groundwaters in the north were unsuitable for irrigation, because of their high sodium levels and salinity. The study results provide a theoretical basis for the sustainable utilization of regional water resources.