Salmas- Plain Aquifer Vulnerability Mapping by SINTACS and GIS Models

Evaluation of groundwater resources vulnerability to pollution can be considered as an effective tool for management decisions. In this study, vulnerability of Salmas plain aquifer to pollution was assessed using SINTACS model and geographic information system (GIS). The SINTACS model consists of seven parameters including: Depth of water table, Infiltration, Unsaturated zone, Soil media, Aquifer media, Hydraulic conductivity and Topography. The vulnerability mapping showed three main zones; low groundwater vulnerability risk zone (risk indexes: 114-82), moderate groundwater vulnerability risk zone (risk indexes: 146-114) and high groundwater vulnerability risk zone (risk indexes:  178-146). The results showed that about 31.47%, 53.42% and 15.11% of the studied area had low, moderate and high vulnerability, respectively. Two tests of sensitivity analyses were carried out: map removal method and single-parameter method, for evaluating the influence of each parameter to pollute the aquifer. The results of both analyses indicated that parameters with most significant impact on the vulnerability risk zones in Salmas area were unsaturated zone and depth of water table.