Determining the most suitable interpolation method for groundwater chemical characteristics mapping

Selection and accuracy of the appropriate methods for zonation and preparing the map of groundwater quality parameters depend on regional condition and availability of data which is an important stage for groundwater management of the region. The purpose of this research is determining the most suitable interpolation method for determining salinity (EC)، nitrate (NO3)، pH and total dissolved salts (TDS) parameters of groundwater and mapping of them by using of geographic information systems in Neyriz plain located in southeast of Fars province. For this aim، different methods of geostatistics including ordinary kriging (OK) and simple kriging (SK) as well as deterministic methods such as inverse distance weights (IDW)، radial basis function (RBF)، local polynomial interpolation (LPI) and global polynomial interpolation (GPI) were used. The result based on the lowest root mean squared error (RMSe) and mean absolute error (MAE) showed that simple kriging (SK) method is the most appropriate method for salinity (EC) mapping (RMSe=3907. 53 and MAE=2911. 05)، TDS mapping (RMSe=2587. 19 and MAE=1936. 48)، pH mapping (RMSe=0. 196 and MAE=0. 143) and NO3 mapping (RMSe=4. 868 and MAE=3. 839) among all the methods in the study area. Finally، the results of this research indicated that geostatistical methods have higher priority than deterministic methods and thus are selected as suitable methods in Neyriz plain.