Assessment of groundwater vulnerable zones using conventional and Fuzzy-AHP DRASTIC for Visakhapatnam district, India

Given the increasing impact of extreme climate change and the unpredictability of monsoons, the importance of preserving groundwater resources has never been more critical. Conducting a thorough groundwater vulnerability assessment enables one to pinpoint the zones most susceptible to contamination and take proactive measures to safeguard them. This paper is an attempt to enhance the conventional DRASTIC method by integrating Fuzzy Logic and Analytical Hierarchy Processes (FAHP) and applying this approach to the Visakhapatnam district. Spatial data for the seven parameters used in this study were created and analyzed using ArcGIS. The study determines and compares the groundwater vulnerability index using both the conventional DRASTIC method and the FAHP-DRASTIC method. Based on the index values, the groundwater zones in the study area have been classified into five categories: Very Low, Low, Medium, High, and Very High Vulnerability. Model validations were conducted using the ROC-AUC technique against Nitrate concentration. The results reveal that the FAHP-DRASTIC model, with an AUC of 0.92, is the most suitable model for the present study. [Display omitted] •Groundwater vulnerability assessment in Visakhapatnam district using the DRASTIC method and FAHP optimization.•Extensive use of Geographic Information System (GIS) for spatial differentiation and overlay analysis of parameters.•FAHP-DRASTIC method yields more reliable results compared to the conventional DRASTIC method.•About 30% of the study area is highly vulnerable to groundwater contamination.•Validation with nitrate concentration shows FAHP method outperforms with an AUC of 0.92.