Evaluation of GIS and Interpolation Methods in Determination of Spatial Distribution and Classified Groundwater Quality

Groundwater is the most important water resource in arid and semiarid areas. Therefore, groundwater pollution is also important. In this study, spatial distribution of groundwater quality was evaluated in Shoor River basin in Dehaghan County, south of Esfahan Province. For this propose, Kriging, Cokriging and IDW methods were used to predicting spatial distribution of groundwater quality parameters related to 48 wells and Qanats. According to Anderson Darling test, data of water quality weren’t normal distributed, so, they were became normal by COX-BOX transformation. After that, variograme of each parameter was drawn for fitting the best interpolation model. Then, spatial distribution maps of groundwater quality were drawn by ArcGIS. Result showed that, ordinary Kriging was the best interpolation method for most of parameters. According to spatial distribution maps, pollution was aggregated in north of basin that its agreed with hydro geology condition in basin. Also spatial distribution of water quality index (WQI) was determined in area according to Water Health Organization Standard.