Quantitative evaluation of runoff variation and its driving forces based on multi-scale separation framework

Abstract

Study region: The Xiangjiang River (XJR) basin, China. Study focus: On multiple time scales (annual, quarterly, and monthly), there are few comprehensive and comprehensive quantitative evaluation frameworks for the factors that drive changes in watershed runoff. The focus of this study is to use the Range of Variability Approach (RVA) to quantitatively analyze the changes in the overall hydrological regime of the basin. The Budyko model and the deterministic hydrological process model (ABCD model) were then used to quantitatively separate the factors affecting runoff in the monthly window, and to clarify the differences in the runoff driving force at different time scales. New hydrological insights for the region: After the mutation, the runoff of the XJR basin increased by 11%, and the changes in the five groups of hydrological and ecological indicators indicated that the ecological response process of the basin was undergoing negative changes. The contributions of the driving forces on different time scales show significant differences: the climatic factor is the dominant factor of the runoff change on the interannual scale. However, on the seasonal scale, human activities have a greater weight in spring, accounting for 82 % of the total. On a monthly scale, it presents a more complicated situation. Human activities contribute significantly in February, May, and October (60 %, 52 %, and 54 %), while climate factors are the main driving factor in the remaining months (51–170 %).

Keywords

• Ecohydrology
• The Budyko model
• The ABCD model
• Driving factor
• Xiangjiang River basin