Assessment of Groundwater Vulnerability of Golpayegan Plain Using DRASTIC Method Optimization

Assessment of Groundwater Vulnerability of Golpayegan Plain Using DRASTIC Method OptimizationQualitative and potential of contamination evaluation of groundwater resources is necessary for contamination protection and their effective management. The Golpayegan study area as one of the most important plains of Isfahan province and one of the most important agricultural areas, has been exposed to nitrate contamination. Therefore, investigation of vulnerable areas of the aquifer in this area with proper method has a more importance. In this study, at first, DRASTIC method was applided to determining the vulnerable areas of Golpayegan plain. Then, to optimizing the DRASTIC method using genetic algorithm, the objective function was defined to the genetic algorithm and by maximizing the objective function, the optimum weights of the DRASTIC parameters were obtained. Also Sugeno fuzzy logic method was used to improve the weights of the DRASTIC method. Nitrate concentration data and its correlation index with vulnerability were used to evaluate the validity of the proposed methods. Correlation indices showed that the optimized DRASTIC using the genetic algorithm has a higher correlations with nitrates and presented the better results than the genera DRASTIC for the region. Optimized map using Genetic Algorithm method showed respectively 6, 23, 34, 21 and 16% of the plains are located in areas with very low, low, moderate, high and very high vulnerability.Correlation indices showed that the optimized DRASTIC using the genetic algorithm has a higher correlations with nitrates and presented the better results than the genera DRASTIC for the region. Optimized map using Genetic Algorithm method showed respectively 6, 23, 34, 21 and 16% of the plains are located in areas with very low, low, moderate, high and very high vulnerability.Keywords: Aquifer, Contamination, DRASTIC, Fuzzy Logic. Golpayegan Plain.