Mapping of Groundwater Salinity Using Dual Reciprocity Boundary Element Method in Nuq Region, Rafsanjan

In this study, a new numerical method based on Dual Reciprocity Boundary Element Method (DRBEM) is presented to interpolate scattered data. For this purpose, water samples were taken from 120 wells in Nuq region, Rafsanjan, for salinity measurements. The proposed estimator was compared with respect to its precision with the conventional ones, i.e., ordinary kriging and inverse distance weighting (IDW) while the spatial mapping of ground water salinity was performed in the study area. Besides, a more revealing measure of performance was obtained by computing the mean rank of each interpolation method. Results revealed the superiority of DRBEM over the kriging and IDW methods due to its lower root mean square error (RMSE) and relative root mean square error (RMSE%) as well as its higher goodness of prediction index (G) . It was also found that DRBEM is the most accurate one when the mean rank and standard deviations of the ranks are used to avoid the outlier effects in assessing the prediction performance of the three methods. Nevertheless, further research is required before DRBEM could be properly combined with ancillary variables to improve the interpolation performance and to develop a user-friendly algorithm that can be implemented in a GIS package