Abstract:
The aim of this work was to explore the characteristics of baseflow evolution in the Beiluo River Basin, to identify the dominant factors affecting baseflow changes, and to provide some scientific basis for water resource management in the basin. The hydrometeorological data and vegetation data of the Beiluo River Basin from 1982 to 2020 were used, applicability of a total of seven baseflow segmentation methods, including time-step methods (FI, SI, LM), digital filtering methods (Lyne-Hollick, Chapman, Chapman-Maxwell, and Eckhardt), were compared. The trend mutation test and wavelet analysis were used to explore evolution of baseflow, the elasticity coefficient method combined with least squares method was used to quantitatively assess relative contribution of climate change and vegetation cover to baseflow changes. Among the seven baseflow partitioning methods, the Lyne-Hollick filtering method (multi-year average BFI = 0.447, NSE = 0.927,
R2 = 0.836, MRE = 9.93%) was found to have the highest estimation accuracy, and the partitioning results reflected the stability and lag of baseflow well, and the daily baseflow process line was more in line with the actual characteristics. The baseflow was found to be bimodal in the basin on the intra-annual scale and on the intra-annual scale. The annual base flow showed a decreasing trend (−0.14 mm/a), but a sudden change occurred in 2004. The cyclic change of base flow was found to be controlled by the first main cycle (23a), the base flow showed a continuous decreasing trend in the future. Increase in NDVI was the dominant factor (contributing to 62.7%) leading to decreased base flow in the Beiluo River Basin. Increase in NDVI was a dominant factor (contribution rate of 62.82%), increase in potential evapotranspiration (contribution rate of 27.08%) and decrease in precipitation (contribution rate of 9.71%) also played a role in the decrease of base flow. These data provide scientific support for sustainable management of water resources and construction of ecological civilization in the Beiluo River Basin.