Comparison of GIS-Based Intrinsic Groundwater Vulnerability Assessment Methods: DRASTIC and SINTACS

Abstract

The possibility of contaminants percolating and diffusing into the groundwater system is referred to as groundwater vulnerability. When groundwater once gets polluted it is very difficult to process/clean it so, measures must be taken to assess the vulnerability of the groundwater for effective groundwater conservation and management planning. This study aims to evaluate and map the vulnerability of Raipur city using the SINTACS and DRASTIC models and to compare their effectiveness between them. To assess the hydrogeological setting and evaluate aquifer vulnerability, each model includes seven environmental parameters (aquifer hydrogeologic features, effective infiltration, topographic slope, soil media, water table depth, unsaturated conditions, and hydraulic conductivity). The parameter data sets are evaluated in a Geographical Information system (GIS) environment to get the vulnerability index (VI), the index is categorized into five classes that show low to high vulnerability. The area under the low class for DRASTIC and SINTACS is 26.14% and 20.34% respectively whereas for the highly vulnerable class it is 15.54% and 22.54% respectively of the total area. By comparing the 15-groundwater sample value of nitrate concentration on the two vulnerability maps it was found that the SINTACS method result was shown to be significantly associated with the nitrate concentration with an accuracy of 86.7 percent.