An optimized baseflow separation method for assessment of seasonal and spatial variability of baseflow and the driving factors

Baseflow is an important component of river or streamflow. It plays a vital role in water utilization and management. An improved Eckhardt recursive digital filter (IERDF) proposed this study. The key parameter maximum baseflow index (BFImax) were estimated using the minimum smoothing method to improve estimation accuracy. generally considered BFImax 0.80, 0.50 0.25 according drainage basin’s predominant geological characteristics often leads significant errors regions that have complex subsurface hydrologic conditions. IERDF accuracy by avoiding arbitrary values. was applied for separation upstream Yitong River, tributary Second Songhua its performance evaluated comparing results obtained isotope-tracer data. also compared with nine techniques belonging filter, BFI HYSEP methods. calculation rainfall infiltration recharge coefficient at different locations along River’s mainstream period 2000–2016. showed significantly process line IEDRF consistent isotope 18O. stability reliability when River. alone increase from downstream. proportion total flow decrease time. intra-annual variability due varying climatic conditions characteristics. highest observed middle reaches summer surplus power generation. research provided valuable information on runoff mode determination, which can be used resources assessment optimization economic activity distribution region.