Nitrate measurements The nitrate concentration was selected as a parameter for the initial contamination in the calibration ofthe DRASTIC model. Analysis and sampling were conducted on 27 agricultural wells. The significance of this study is on its three-year monitoring of nitrate samples. Three samples were collected onMay 2010,May 2011, and May 2012. In this study, the 2010 and 2012 nitrate samples were usedbecause the last sample ismore reliable andcloser to the actual