Hydro-geospatial modelling of groundwater potential zones in the soar valley and adjacent terrains of the Kumaon Lesser Himalaya using an integrated AHP–GIS framework

Abstract Groundwater depletion has emerged as a critical challenge for sustainable urban development, particularly in the Himalayan terrain where complex terrain, geological heterogeneity, and dynamic environmental conditions hinder recharge processes. The present study delineates groundwater potential zones (GWPZs) in the densely populated and rapidly urbanizing Soar Valley and adjacent terrains of Pithoragarh district of Kumaon Inner Lesser Himalaya, by integrating Remote Sensing (RS), Geographical Information System (GIS), and the Analytic Hierarchy Process (AHP) within a multi-criteria decision analysis (MCDA) technique. The study utilized IMD rainfall data (2021–2024), Valdiya’s (1980) geological map, 2025 ASTER GDEM Version 3-derived slope, drainage density and elevation datasets, lineament data derived by integrating DEM-based lineament extraction with structural information obtained from the Geological Survey of India (GSI-Bhukosh), 2025 Sentinel-2 LULC data (Esri), and 2025 geomorphological data from GSI-Bhukosh. A total of eight thematic layers- rainfall, geology, lineament density, land use/land cover (LULC), geomorphology, drainage density, slope, and elevation were standardized, weighted using AHP, and integrated through a weighted overlay approach to generate the GWPZ map. The AHP-generated criterion weights showed reasonable consistency, with a consistency ratio (CR) of 4.4%, which is significantly below the acceptable threshold of 10%. The results reveal that only 0.01% of the study area falls under very high groundwater potential, while 92.76% lies in high to moderate potential zones and 7.23% in low to very low categories, indicating a predominance of high to moderate groundwater potential zones under the selected criteria, weights, and classification thresholds rather than directly indicating groundwater availability. Rainfall, geology, and lineament density received the highest relative weights in the AHP assessment, followed by LULC, geomorphology, drainage density, slope, and elevation, reflecting their greater importance within the adopted AHP weighting framework. Model validation using the Area Under the Receiver Operating Characteristic Curve (AUC-ROC) yielded an AUC of 0.795, indicating good discriminatory performance with respect to the field-observed spring locations and available secondary spring locations. The novelty of the study lies in the utilization of an integrated AHP-GIS framework for spatially explicit groundwater potential evaluation in a fast-urbanizing Himalayan valley, which evaluates topographical, geo-hydrological, and land-use factors simultaneously. The derived GWPZ map provides a spatial assessment of relative groundwater suitability under the selected criteria, weights, and thresholds and can serve as a screening framework for identifying areas for detailed hydrogeological investigation, recharge and conservation planning, and climate-adaptive urban planning in the Himalayan terrain.