Assessing the groundwater quality by applying fuzzy logic in GIS environment– A case study in Southwest Iran

Water quality is a key environmental issue concerning the agricultural sector. Here, the application of fuzzy set theory for decision-making in the assessment of groundwater quality for agricultural purposes is being discussed. The experiments conducted in this study area located, Shahrekord plain that, lies in the Chaharmahal and Bakhtiari province, in the southwest Iran. Four groundwater parameters (EC, Mg, Na and Ca) are selected for water quality analysis and thematic maps are drawn for each of the parameters with the Kriging model. Different Fuzzy membership functions obtained from the related literature were employed and the weights for each parameter were calculated according to Analytic Hierarchy Process (AHP) that relies on pair wise comparisons. The Fuzzy theory showed 14.22% of the study area as having high groundwater quality, 19.86 % as having moderate quality, 48.90% as having margin quality and 16.99% as having poor quality. In order to evaluate the accuracy of this method, eight different points were randomly selected. It is concluded that the Fuzzy method allows for obtaining results that correspond to the current conditions in the study area.