International Journal of Science and Technology (IJST)

A Comprehensive Water Balance Assessment of Northern Pakistan’s Catchment Based Using the Budyko Framework Approach

This study presents a comprehensive hydrological evaluation of the Astore catchment(Northern Pakistan), integrating long-term observational data with advanced modeling techniques to assess water balance dynamics and runoff simulation accuracy. Spanning two decades (2000–2020), the dataset includes key parameters such as annual rainfall (1144 mm), actual evapotranspiration (278 mm), and groundwater recharge (494 mm), offering insights into the catchment’s hydrometeorological behavior. These variables are influenced by diverse environmental factors including topography, land use, soil composition, and microclimatic conditions. To simulate runoff and validate hydrological responses, a Budyko-based model was calibrated at both monthly and yearly scales. The optimization of parameters Smax, α1, α2, and d yielded high-performance metrics, with a Pearson correlation of 0.99, NNSE of 0.97, and RMSE of 0.02. These findings validate the model’s capability to replicate observed runoff patterns with remarkable precision. Visual comparisons between observed and simulated rainfall and runoff data underscore the model’s effectiveness in capturing seasonal variability and hydrological trends. Furthermore, sensitivity analysis revealed the model’s responsiveness to parameter changes, highlighting the importance of careful calibration for reliable predictions. The integration of empirical data and robust simulation techniques provides a valuable framework for understanding catchment-scale water dynamics. This approach supports improved forecasting, resource management, and environmental planning, particularly in regions vulnerable to hydrological extremes such as landslides and droughts. The findings contribute to the broader field of hydrological modeling by demonstrating the utility of Budyko-based frameworks in complex mountainous terrains.