Author(s): Xiaoyan Zhai; Ronghua Liu; Liang Guo; Zhaohui Li

Linked Author(s): Ronghua Liu

Keywords: Catchment drainage area threshold; Flow state; Mean change point method; Small and medium-sized rivers

Abstract: The critical thresholds of flow states directly influence the morphology of river networks. Using the D8 algorithm and mean change point method, the relationship between catchment drainage area threshold and river source density is established, and the critical threshold between overland flow and streamflow is determined. A total of 2859 small and medium-sized rivers in mountainous regions across China are selected for case study. Results showed that a power function relationship with the form of y=kxa was determined between catchment drainage area thresholds and corresponding river source densities for all the rivers. The values of coefficient k for all the rivers ranged from 2.39 and 878.39 with an average value of 352.76, which tended to gradually increase from north to south and from west to east in China. The values of power a ranged from -1.1 and -0.9 for 96% of the rivers. The critical threshold between overland flow and streamflow was determined as 0.375 km2,0. 5 km2 and >0.5 km2, respectively for 37.39%, 60.30% and 2.30% of the rivers. This study is expected to provide references for the extraction of digital river networks and the analysis of unit hydrographs.

DOI: https://doi.org/10.3850/iahr-hic2483430201-400

Year: 2024