Investigation of possibility of groundwater quality zonation in arid regions using geostatistic (case study: Yazd-Ardakan plain)

Nowadays، due to water resources scarcity (especially in arid regions)، groundwater resource quality and quantity management is essential. In this research، spatial variations of chemical characteristics of groundwater such as EC، Na، Mg، Ca، HCO3، TH and TDS were investigated in one-year period (2010-11) based on the data collected from 42 deep wells of Yazd-Ardakan Plain. In order to prepare zonation characteristics of water quality، Simple kriging was used. The results showed that the fitted model to the variogram of Ca، TDS and EC are Gaussian. Homogeneity of variogram model of these three parameters can be considered due to positive، significant and strong correlation between them and the same spatial variation in aquifer. Best Model variogram for Na، Mg، HCO3، TH is spherical. Effective range of investigated indices was approximately obtained between 5 to 104 kilometers. Effective range of EC، TDS and TH and the effective range of Na and HCO3 were very similar in the plain. RMSE criteria was obtained less than 40 percent for all indices that shows the accuracy of estimates. Agreement of correlation between the observations and the maps showed good accuracy of variogram model and Simple kriging method for zonation of characteristics of ground water quality in Yazd-Ardakan plain.