Evaluation of baseflow seperation models for Büyük Menderes River subbasins

Effective management of baseflow is crucial for understanding and forecasting streamflow, particularly under drought conditions where baseflow constitutes a significant portion of total streamflow. This study evaluates baseflow separation methods using data from eight hydrological stations in Türkiye, spanning various climatic and geographic conditions. Three baseflow separation techniques, the Digital Filtering Method (DFM), the Smoothed Minima Technique of the British Institute of Hydrology (SMTBIH) and the Revised Smoothed Minima Technique of the British Institute of Hydrology (RSMTBIH), are employed to analyze baseflow data and calculate the Baseflow Index (BFI). The research reveals that while all methods provide similar baseflow estimates, distinct seasonal patterns emerge depending on station-specific characteristics such as elevation and catchment size. Higher elevation stations exhibit significant seasonal variations, mainly due to snowmelt, whereas stations with larger catchment areas experience pronounced peak flow events that influence baseflow values. The study emphasizes the importance of considering both catchment-specific attributes and seasonal variations in hydrological assessments. Recommendations include establishing comprehensive monitoring systems, integrating climate change scenarios into future research, and developing catchment-specific management strategies. Regular updates to baseflow separation methods are also advised to incorporate the latest research findings and technological advancements. These measures are essential for enhancing the accuracy and effectiveness of water resource management and ensuring sustainable use of water resources.