Groundwater Vulnerability Assessment from a Drinking Water Perspective: Case Study in a Tropical Groundwater Basin in Eastern India

This study assessed the groundwater vulnerability of the Rana groundwater basin, Odisha, India. The study attempts to optimize the DRASTIC method by modifying the weights and ratings assigned to the DRASTIC parameters using the analytical hierarchy process. Sensitivity analysis has been carried out to quantify the influence of each parameter. The groundwater vulnerability results obtained from both DRASTIC and modified DRASTIC methods were validated using the water quality index (WQI) values computed through groundwater quality data at 25 sampling locations. The results revealed that the index values generated through modified DRASTIC possessed a higher correlation with the WQI compared with the original DRASTIC method. The groundwater level and net recharge were found to be having a greater influence on groundwater vulnerability. The obtained vulnerability maps from the modified DRASTIC method revealed that about 70% of the area was under very low to low vulnerable zones, whereas 14% of the area was under high to very high vulnerable zones. It was also observed that most of the high to very high vulnerable zones were located on the agriculturally dominated areas lying in the northern part of the basin. The result obtained will play an immense role in adopting management practices to conserve the groundwater quality of the study basin. (C) 2021 American Society of Civil Engineers.