Assessment Of Groundwater Pollution In Bajestan Plains For Agricultural Purposes Using Indicator Kriging

Unethical and inequitable exploitation of groundwater resources has led to reduce the amount and the quality of these water. In this study Ordinary Kriging (OK) and Indicator Kriging (IK) methods were used as geostatistical approach for preparation of thematic maps of the groundwater quality in Bajestan plain for agricultural purposes. First each of the measured parameters was compared with the acceptable standard limits based on the FAO standard. Three parameters such as Na، SAR and EC were greater than their respective groundwater pollution cutoff value. First، data normality was investigated and Log-transformed was applied to some parameters. The variogram analysis for each parameter was calculated. The evaluation criteria were ME and RMSE with the Cross Validation method. Then OK was used to analyze the spatial variability and quantitative potential maps، whereas IK was used to analyze groundwater quality parameters equal to or greater than the pollution threshold values. The results showed that the parameters of EC، SAR، and Na in most wells were higher than the threshold value and the salinity and sodium adsorption ratio was high in most of the wells. Most of the groundwater in the study area is restricted to EC. More than 59 wells in which water quality is the most important factor in reducing and uncontrolled utilization of them for long time caused salinity and reduce soil permeability.