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

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

ir DESERT 19-1 (2014) 83-90 Zoning of Groundwater Contaminated by Nitrate Using Geostatistics Methods (Case Study: Bahabad Plain, Yazd, Iran) Z. The two interpolation techniques of kriging and inverse distance weighting (IDW) were used to obtain the spatial distribution of groundwater qualityparameters by means of Arcview GIS 10 software. The results of this study showed that the kriging method is more accurate than IDW for groundwater quality mapping, based on the lower root mean square error (RMSE) of kriging. At present, most arid and semi-arid regions, such as Iran, are facing high nitrate concentrations in drinking water, the most important reason for which is the introduction of agricultural runoff and urban and industrial sewage to groundwater resources (Firat, Ersoy et al. , 2010; Motaghian and Mohammadi, 2012; Jafari et al. As there is no study which investigates nitrate concentrations in the groundwater of the Bahabad plain in Yazd, this research aimed to range the contamination of groundwater resources with nitrate using kriging and IDW methods. Figures 4 and 5 show the zoning of nitrate contamination in groundwater of the Bahabad plain by kriging and IDW methods, respectively. (2013) evaluated geostatistical methods for estimating spatial variables, including nitrate and sodium, in the groundwater of 276 wells in Mashhad (Iran). 5. Conclusion According to the results of the current study, kriging seems to be more appropriate than IDW for estimating the nitrate content in the groundwater of the Bahabad plain. Application of Geostatistical Methods for determining nitrate concentrations in Groundwater (case study of Mashhad plain, Iran).