Modeling groundwater recharge dynamics in the jewha watershed using the WetSpass-M model under tropical conditions

Effective and sustainable groundwater management necessitates a thorough understanding of the spatial and temporal patterns of groundwater recharge, particularly in data-scarce regions such as the Jewuha watershed in tropical Northern Ethiopia. This study applied the GIS-based WetSpass-M model to quantify key water balance components, namely actual evapotranspiration (AET), surface runoff, and groundwater recharge. A comprehensive set of spatial input datasets including land use, slope, elevation, soil texture, temperature, potential evapotranspiration, wind speed, and groundwater depth were systematically prepared and converted into ASCII format using GIS processing techniques. Model simulations revealed that the long-term mean annual rainfall of 889.8 mm was partitioned into AET of 436.0 mm (49.0%), surface runoff of 299.5 mm (36.0%), and groundwater recharge of 124.0 mm (15.0%). The results demonstrate the WetSpass-M model's capacity to reliably simulate spatial and temporal variability in water balance components, establishing it as an effective tool for hydrological assessment in data-limited environments. The spatial distribution of these components is primarily governed by land use and land cover characteristics, topography, and prevailing hydroclimatic variables. This study represents a novel application of the WetSpass-M model within the Jewuha watershed, providing a robust framework for characterizing water balance dynamics and generating critical insights to support groundwater management and long-term resource planning. The findings further affirm the model's value in guiding hydrological decision-making across comparable data-scarce basins including delineating optimal sites for groundwater extraction, prioritizing recharge zones, and informing land use and water conservation strategies.