Groundwater resilience and recharge enhancement policy for the East Kolkata Wetlands

Abstract

Enhancing groundwater resilience in ecologically sensitive wetlands requires reliable identification of recharge-prone areas to support evidence-based management. This study develops an integrated geospatial framework for delineating groundwater recharge potential zones (GWRPZ) across the East Kolkata Wetlands (EKW), a Ramsar-listed urban wetland. Fifteen geo-environmental conditioning factors were integrated with three multi-criteria decision-making models, TOPSIS, VIKOR, and EDAS, using a statistically optimized pixel-based sampling strategy based on Cochran’s formula (n = 16,468). Model performance was evaluated using ROC-AUC, coefficient of determination (R²), sensitivity analysis, and bathymetric-based validation. EDAS achieved the highest predictive performance (ROC-AUC = 0.939; R² = -0.803), identifying 36.60% of the wetland as having high recharge potential. Bathymetric-based validation confirmed a significant relationship between water depth and recharge potential (R² = 0.451), supporting the reliability of spatial predictions. Sensitivity analysis identified NDWI, NDVI, canal density, and lithology as dominant positive controls, whereas rainfall and groundwater storage showed negative responses associated with urbanization and altered hydrological processes. The framework supports targeted recharge enhancement through Managed Aquifer Recharge (MAR) and Aquifer Storage and Recovery (ASR) while providing a transferable decision-support approach for wetland restoration, climate adaptation, sustainable groundwater governance, and advancing SDGs 6, 13, and 15.