Vulnerability of Khash-Plain Aquifer, Eastern Iran, to Pollution Using Geographic Information System (GIS)

Abstract

This research is an evaluation of vulnerability of Khash-plain aquifer to pollution, using DRASTIC model and Geographic Information System (GIS). Seven environmental parameters have been used to represent the hydrogeological nature of the aquifer. These parameters are: depth of water table, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity. This study shows that the Khash aquifer consists of two main zones: low groundwater vulnerability risk zone (risk indexes 92-121) and moderate groundwater vulnerability risk zone (risk indexes 122-148). Areas with moderate and low risk zones comprise 75.5% and 24.5% of the studied area, respectively. Statistical analyses have been carried out using nitrate ion concentration. Two tests of sensitivity analyses were carried out: the map removal and the single-parameter sensitivity analyses. Based on the characteristics of the studied area, the results from both map removal and single-parameter sensitivity analyses showed that the net recharge parameters have the most significant impact on the vulnerability risk zones.