Assessing the Effect of Land use Changes on Groundwater Quality of Zarand Plain using Satellite Images and Geostatistical

Population enhancement and consequently increasing of land use changes and excessive exploitation of ground water resources, not only has reduced the quantity of groundwater resources but also has degraded the quality of these resources. The study and investigation of groundwater resources quality can lead to the correct management of these resources. So the purpose of this study was investigation of the effect of land use changes process on groundwater resources quality and also comparison of different Geostatistical methods for water quality zoning in terms of EC and SAR parameters for agriculture and irrigation using Wilcox method. For this aim Landsat satellite images of the TM 2000 and OLI 2014 sensors using Maximum Likelihood Method was used. Wilcox method was used for determining the quality of groundwater resources in terms of EC and SAR parameters. Also, RMSE and R criteria were used in order to compare symmetry of fitted models to data. The results showed that Simple Kriging method with Circular Variogram Model and the amount of RMSE equal to 1782.19 and R equal to 0.81232 was the best method for EC and Ordinary Kriging Method with Gaussian Variogram Model and the amount of RMSE equal to 3.29534 and R equal to 0.79791 was the best method for SAR in terms of groundwater quality zoning. The conclusion showed that an increase of the area of urban and agricultural uses and also 13% increase in groundwater destruction have happened in study area which the most important causes were excessive exploitation and using organic fertilizer. Generally, due to the increasing of the area of urban and agricultural uses, an increase of 2% of pollution in terms of EC and an increase of 5.5% of pollution in terms of SAR has occurred in groundwater resources.