Characteristics and attribution analysis of runoff and sediment evolution in the Wei River mainstream, China

Abstract

This study evaluates the characteristics of river runoff and sediment changes in the Wei River mainstream over the past 50 years based on runoff and sediment data and meteorological data from 1971 to 2020 at the Huaxian hydrological station in the lower reaches of the Wei River. The main research methods are the Mann–Kendall method, wavelet analysis, cross-wavelet analysis, and cumulative curve method. The results show that there is no significant decreasing trend and abrupt change in runoff volume in recent years, the decreasing trend of sediment transport is obvious, and the abrupt change occurs around 2006. The dominant periodicity of runoff is 12–13a, and the dominant periodicity of sediment transport is 5a. There is only a significant resonance periodicity of 3–5a in 1980–1990, which is roughly a positive correlation. The runoff–sediment series can be divided into four time periods, and the reasons for the change in the runoff–sediment relationship are different in each time period. The precipitation factor has a slightly greater impact on runoff and a weak impact on sediment transport, with contribution rates of 21.2 and 7.6%. Human activities such as subsurface changes and water conservancy construction have a greater impact on runoff and sediment load, with contribution rates of 78.8 and 92.4%. HIGHLIGHTS In this study, the resonance period between water and sediment is deeply studied by cross-wavelet analysis, and the mutual influence law between water and sediment in the mainstream of Weihe River is revealed.; This study quantitatively assessed the impacts of climate change and human activities on runoff and sediment transport and analyzed the impact process in detail.;

Keywords

• climate change
• cross-wavelet
• human activities
• land use
• runoff–sediment relationship
• wei river