Study On The Spatial Variability Of Chemical Characteristics Of Groundwater In Keriya Oasis, Xinjiang

Keriya oasis is located in the Northwest extreme arid region of China, where there is less precipitation and a deficiency of groundwater. In the Oasis, it depends mainly on agriculture and animal husbandry. Agricultural production depends on exploitation of groundwater while the growth of crops is related closely with the quality of groundwater. Therefore, it is significant to the reasonable utilization of groundwater, effective utilization of water resource, and preventing the ecological environment from deterioration to study the chemical characteristics of groundwater and evaluate the distribution of groundwater quality.In this paper, groundwater samples were collected in Keriya Oasis. Chemical characteristics were analysed for the groundwater samples, and the ion contents of Ca²⁺, Mg²⁺, K⁺+Na⁺, HCO₃^-,CO₃^2-, Cl^-, SO₄^2-, the total soluble solids and pH value were measured. The measured data of the chemical characteristics of groundwater were analyzed and examined by SPSS statistical software. The ions, such as HCO₃^-, K⁺+Na⁺ and Cl^-, which related closely with the quality of groundwater were extracted by using the principal component analysis and the regression analysis. The quality of groundwater is alkaline, and it is weak hard-water or extremely hard water. The fresh water, low mineralized water and middle-mineralized water all exist in the study area. The two groundwater types, HCO₃^-Na type and HCO₃^-Cl^-Na type, exist in the study area. The principal component model and the regression model between the total dissolved solids and ions content were established in this paper.The spatial variation characteristics of the groundwater were studied in this paper. It shows that the total dissolved solids, HCO₃^-, Cl^- and K⁺+Na⁺ all have an increasing trend from the top to the middle and the edge of the alluvial fan. In the perpendicular profiles of the flow, the top profile of the alluvial fan, the middle profile of the alluvial fan and the edge profile of the alluvial fan, all show that the total dissolved solids, HCO₃^-, Cl^- and K⁺+Na⁺ in the east are all bigger than those in the west. The total dissolved solids, content of the HCO₃^-, Cl^- and K⁺+Na⁺ in the soil water decreases along the flow. In the perpendicular profile of the flow, the total dissolved solids, content of the HCO₃^-, Cl^- and K⁺+Na⁺ all have an decreasing trend from the west to the east.