Estimation of spatio-temporal variability of groundwater balance components in Kupwara district, Kashmir

Abstract

Groundwater is a critical resource for sustaining agriculture, domestic supply, and ecosystems in the Himalayan region, yet its availability is increasingly threatened by climatic variability, land-use change, and unsustainable extraction. This study assessed the spatial and temporal variability of groundwater balance components in Kupwara district, using the WetSpass-M water balance model. The model integrated meteorological data (rainfall, potential evapotranspiration, temperature, wind speed), land use/land cover, soil texture, topography, and groundwater depth to simulate actual evapotranspiration (AET), surface runoff, and groundwater recharge at monthly, seasonal, and annual scales from 2012 to 2024. Results revealed that annual rainfall averaged 655.7 mm, of which 38–40% was lost to AET, 12% contributed to runoff and 18% percolated as recharge, underscoring the recharge-supportive nature of the basin. Seasonal analysis showed that summer contributed the largest rainfall (291 mm) but was dominated by ET and runoff, while spring exhibited the highest recharge efficiency (43% of rainfall). Autumn and winter emerged as water-stressed seasons, with minimal recharge and ET losses exceeding rainfall inputs. Spatial patterns indicated recharge hotspots in the central and southern basin, while high-runoff zones in the northeast posed localized flood and erosion risks. The study concludes that it maintains a positive water balance but is subject to strong seasonal and spatial heterogeneity. These findings provide a scientific basis for sustainable groundwater management, emphasizing the need to couple ET-reducing practices with recharge-enhancing measures. The outputs also serve as essential input for predictive groundwater models, supporting adaptive strategies under changing climate and land-use pressures.