Zoning of groundwater contaminated by Nitrate using geostatistics method (case study: Bahabad plain, Yazd, Iran)

Abstract

Groundwater quality management is one of the most important issues in many arid and semi-arid regions, including Iran.<br />Nitrate (NO3<br />-) is one of the most common anions contaminating groundwater. This study aimed to range nitrate<br />concentrations in water resources in Bahabad plain in Yazd province. To evaluate the nitrate data in this descriptive study,<br />260 nitrate samples from 13 wells in Bahabad were assessed from 2003 to 2013. The two interpolation techniques of<br />kriging and inverse distance weighting (IDW) were used to obtain the spatial distribution of groundwater quality<br />parameters by means of Arcview GIS 10 software. The results of this study showed that the kriging method is more<br />accurate than IDW for groundwater quality mapping, based on the lower root mean square error (RMSE) of kriging.<br />Nitrate levels in samples from regional wells were lower than standard levels for Iran and the world. However, nitrate<br />contamination tended to increase from 2003 to 2013. Furthermore, the greatest nitrate contamination was found in the<br />southern part of Bahabad. In conclusion, kriging seems to be an appropriate method for estimating nitrate levels in<br />groundwater in Bahabad. We recommend action be taken in order to stop the increasing trend of groundwater nitrate<br />contamination in this area.<br /><br />