Zoning of Groundwater Quality by Using Geostatistical Methods: A Case Study of Razan - Qahavand Plain

Groundwater quality is one of the most important issues in managing of water resources in many arid and semi-arid regions.Changes in the ground water quality endangers agricultural development.The main aim of this study was torange spatial distribution of electrical conductivity (EC) and total dissolved solids (TDS) in groundwater resources in razan- Qahavand plain Using geostatistical Methods.Kalmogorov-Smiranov test in SPSS software was used to evaluate normality of data. Between different interpolation methods, the best one was selected via MAE, MBE, RMSE and R2. Ordinary kriging and local polynorman interpolation method were the best methods of interpolation for EC and TDS respectively. The results of the study showed that the quality of water for drinking, according to Schoeller diagram, is divided into five groups of good (8.72 percent), accepted (46.09 %), inadequate (26.7 %), bad (18.59 %) and temporarily drinkable (0.51 %).