Determination of Groundwater Quality Using a GIS-AHP Based System and Compared with Wilcox Diagram (Case Study: Rafsanjan Plain)

Determining the quality of groundwater is one of the key elements of water usage in drinking, agriculture and industry sectors. Rafsanjan plain is one of the most economical plains in the country due to the existence of pistachio orchards. Therefore, proper management and careful study of groundwater in this plain is essential. The present study was conducted to evaluate the groundwater quality of the Rafsanjan plain with agricultural applications. In the first stage, after selecting the effective parameters in water quality assessment, weighting was performed by Analytic Hierarchy Process (AHP) and then the groundwater quality of the study area was modeled using GIS software. According to the results of the final zoning of groundwater quality, about 1.6% of the study area has very good quality water, 20% has medium quality, 52.7 has poor quality and 25.7 has very poor quality. In addition, based on the statistical analysis of Wilcox diagram, 1.5%, 16.2%, and 60.2% of the wells in the study area had good, medium and poor quality, respectively. Moreover, 22.1% of the wells are not included in the diagram due to very poor quality. This research revealed that a GIS-AHP based method can analyze this kind of data spatially and consistent results could be obtained.