Modeling streamflow dynamics under future land use scenarios using soil and water assessment tools

BACKGROUND AND OBJECTIVES: Land use and land cover change is a major driver of hydrological change, particularly in mountainous basins where hydropower production depends on reliable streamflow. The Suki Kinari Hydropower Project on Pakistan’s Kunhar River is a run-of-river facility that is highly sensitive to such variations. The study objectives were to evaluate the impact of past and projected land use and land cover change on streamflow to provide insights for watershed management and sustainable hydropower operations.METHODS: The soil and water assessment tool were employed to simulate streamflow dynamics under future land use scenarios. The model was calibrated for the period ۲۰۰۰–۲۰۱۱ and validated for ۲۰۱۲–۲۰۱۶ against monthly discharge data from the Garhi Habibullah gauging station. Future land use and land cover projections for ۲۰۵۲ and ۲۰۸۲ were generated using a cellular Automata-Markov chain model based on historical transition probabilities from ۱۹۹۲, ۲۰۰۲, and ۲۰۱۲ satellite observations.FINDINGS: The soil and water assessment tool model demonstrated acceptable performance for monthly simulations (Calibration: R² = ۰.۶۴, Nash–Sutcliffe Efficiency = ۰.۶۲; Validation: R² = ۰.۶۱, Nash–Sutcliffe Efficiency = ۰.۵۲). land use and land cover projections indicate a continuous expansion of urban areas (+۴۰۰ percent by ۲۰۸۲), agricultural land (+۷۲ percent), and barren land (+۳.۸ percent), driven by deforestation (-۳۸ percent) and grassland degradation. Under these projected changes, mean monthly streamflow is predicted to increase by ۲.۶۴ percent in ۲۰۵۲ and ۷.۵۴ percent in ۲۰۸۲, with peak runoffs shifting earlier in the year.CONCLUSION: The study reveals that future land use and land cover changes will significantly increase streamflow and runoff in the Kunhar River Basin, posing potential risks of sedimentation and flooding for the Suki Kinari Hydropower Project. The findings underscore the critical need for a dense hydro-meteorological monitoring network in the upper catchment and the integration of scenario-based modeling into water resources planning. Sustainable land management is essential to mitigate adverse hydrological impacts in mountainous basins.

کلیدواژه ها:

Cellular automata (CA)&ndash ، Markov ، Hydrological modeling ، Land use change ، Suki Kinari ، Watershed management.