Assessment of Khoy Aquifer Vulnerability Using a Combined Method

Population growth, agricultural and industrial development has led to a sharp increase in water use, a decrease in the quantity, quality and pollution of groundwater resources. Appropriate measures to prevent pollution of groundwater resources are the identification of vulnerable aquifers. In this study, combined method (DSM) is the combination of DRASTIC and SINTACS methods, was used to evaluate the vulnerability of Khoy plain aquifer. Both methods use hydrological and hydrogeological parameters of this area to investigate the aquifer vulnerability and zoning of susceptible areas, but each of these methods has inherent characteristics and presents different results. Therefore, in this study due to the similarity of the results of these two. The method has been used simultaneously using combination of their advantages. Validation of each of methods were carried out with measured nitrate values from 26 wells in the study area. The Correlation Index (CI) was calculated between vulnerability maps and nitrate values to validation and compare these methods. The results showed that the CI of combined method is high; therefore, this method is more suitable for assessing the vulnerability of this region. Based on the results of the combined method, 19, 42 and 39 percent of Khoy plain aquifer are located within low, medium and high vulnerable areas.