region of investigation. The other significant point of this research is surveying the nitrate samples in the same month which gives us more accurate correlation. In spite of the difficulty of data collection, the authors gathered data in three years to monitor nitrate concentrations and identified which model is the most suitable for Kerman plain by using correlation coefficient. For that correlation coefficient, the last nitrate sample was normalized. A global positioning system was used to determine the exact location of the wells (Fig. 6).