An investigation of groundwater vulnerability in the North 24 parganas district using DRASTIC and hybrid-DRASTIC models: A case study

Abstract The identification of a groundwater contamination risk zone has been found to be a useful approach for managing ground water resources. As such, despite the fact that North 24 Parganas in West Bengal has been in the spotlight since the mid-2000s due to significant groundwater contamination, no work has been done on groundwater vulnerability zonation mapping. The current study is, therefore, aimed to identify the major susceptible zones of aquifer contamination in various parts of the North 24 Parganas district using the DRASTIC and certain improved version of DRASTIC techniques, as well as eight hydro-geological parameters. A sensitivity analysis was also carried out in order to determine the most sensitive parameter for ground water vulnerability. Furthermore, a total of 64 ground water samples were collected across the district, and the water quality was compared to the DRASTIC results to determine their accuracy. The results from four DRASTIC models show that about 14.20% of the study area is covered by low vulnerable zone, 24.28% by moderately high, 37.67% by high, and about 20.45% of the area is under very highly vulnerable zone. Despite the inclusion of four models in this study, a comparison of the four models shows that the modified DRASTIC AHP is the most suited and reliable for evaluating groundwater susceptibility, with an accuracy level of 87.50 percent. Consequently, the ideas and vulnerability zone maps might provide a scientific foundation for long-term planning and management and groundwater conservation in the North 24 Parganas and peripheral zones.