Vulnerability Analysis of Groundwater by Using DRASTIC Method (Case Study: Najafabad Aquifer)

The existence of important sources of point and non-point pollutants that resulted from human activities on the ground and their infiltration to the groundwater, reduces water quality, therefore, prevention of this pollution is important in water resources management. The objectives of this study include mapping vulnerable places of Najaf-abad plain using DRASTIC method, determining and mapping hydrogeological parameters of contaminant transfer, comparison of groundwater contamination parameters in different places with study area and ranking conservation-management practices in Najaf-abad aquifer in each city. This study is a descriptive-analytical type of study. In this research, seven information layers including groundwater table depth, pure recharge, aquifer, soil, topography, unsaturated parameters, and hydraulic conductivity of aquifer were used to assess vulnerability of groundwater contamination. According to the results, 1.744 % (162.74 hac), 16.188% (1510.52 hac), 54.615% (5096.29 hac), 17.761 % ( 1657.37 hac), and 9.693% (904.44 hac) out of the total area are prone to free, low, moderate, high, and very high risk of pollution, respectively.