Evaluation of the SINTACS-LU model capability in the analysis of aquifer vulnerability potential in semi-arid regions

Detection of aquifer vulnerable areas can highlight preventive actions for groundwater contamination. Different models have been presented for the evaluation of vulnerability that one of the most regular and well-known models of the overlapping index as the SINTACS-LU (Soggiacence, actual infiltration, non saturated zone, typology of overburden, hydrogeological characteristics of the aquifer, hydraulic conductivity, topographic Slope) model was considered in this research. In fact, this model has been extended based on the impact of land use parameters in the vulnerability evaluation. Purpose of this study is the qualitative evaluation of Birjand plain aquifer vulnerability using the SINTACS-LU model. For this, the Birjand plain aquifer in the statistical periods of 2013-2018 has been evaluated. According to the results of this assessment, the SINTACS-LU vulnerability zoning map reveals that 15 percent of the studied region has the vulnerability of medium to high, 75 percent of the area has a high vulnerability, and 10 percent has the too high vulnerability. In order to the verification of the SINTACS-LU model, the relationship between the vulnerability index and the obtained nitrate concentration values from 21 groundwater samples were assessed. The correlation coefficient between the SINTACS-LU vulnerability index and the nitrate concentration was 75 percent, which indicates the appropriate correlation of this model with the nitrate concentration as the indicator of the groundwater contamination.