Peak discharge estimation in data-scarce regions: a comparative study of methods for Syrian ungauged basins

Accurate estimation of peak discharges in small, ungauged basins is critical for flood risk management, particularly in developing countries where hydrometeorological data are scarce. This study compares empirical/conceptual methods (Fuller’s formula, Rational Method), event-based models (EBA4SUB), and continuous modeling (COSMO4SUB) across three Syrian catchments. Results show that empirical approaches are highly sensitive to parameter selection and often underestimate peak discharges, while event-based models, though more flexible, remain influenced by user-defined assumptions such as hyetograph shape and antecedent moisture conditions. The COSMO4SUB continuous modeling approach provides a robust alternative, reducing subjective choices and better representing physical catchment processes, including soil saturation, runoff generation, and temporal rainfall variability. These features make COSMO4SUB particularly suitable for data-scarce environments, offering a reliable tool for flood estimation, infrastructure design, and resilience planning.