Multifarious methods of baseflow estimation for typical catchments in the Yellow River Basin, China

Baseflow is crucial to maintaining river flow during low rainfall periods. The baseflow estimation is important to water supply and ecological environmental protection in the Yellow River Basin (YRB), China. This paper comprehensively assessed the applicability of four single-parameter digital filtering, recursive digital filtering, and HYSEP (Streamflow Hydrograph Separation) methods across four typical catchments in the Yellow River Basin: Zuli River Basin, Kuye River Basin, Tuwei River Basin, and Jingle sub-basin. We also investigated annual and monthly variations in baseflow. We found the standard deviation and coefficient of variation of baseflow index through recursive digital filter were relatively small. And the baseflow process line was smoother and more reasonable in typical year and typical storm-flood events, which conformed to the damping and hysteresis effect of underlying surface. Thus the recursive digital filter method had the best performance, which was recommended for baseflow separation in the YRB. The estimated baseflow index of typical basins were between 0.354 and 0.502. In addition, inter-annual baseflow showed a decreasing trend and intra-annual baseflow was characterized by uneven distribution, which was subject to the characteristics of each basin. As baseflow is important for the YRB, suitable assessment of baseflow is crucial to efficient management of water resource.