Variations in runoff,sediment load,and their relationship for a major sediment source area of the Jialing River basin,southern China |
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| Authors: | Yiting Shao Xingmin Mu Yi He Kai Chen |
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| Institution: | 1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences & Ministry of Water Resources, Yangling, China;2. Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, China;3. Longnan Hydrology and Water Resources Survey Bureau in Gansu Province, Chengxian, China |
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| Abstract: | Investigation of the variations in runoff, sediment load, and their dynamic relation is conducive to understanding hydrological regime changes and supporting channel regulation and fluvial management. This study is undertaken in the Xihanshui catchment, which is known for its high sediment-laden in the Jialing River of the Yangtze River basin, southern China, to evaluate the change characteristics of runoff, sediment load, and their relationship at multi-temporal scales from 1966 to 2016. The results showed that runoff changed significantly for more months, whereas the significant changes in monthly sediment load occurred from April to September. The contributions of runoff in summer and autumn and sediment load in summer to their annual value changes were greater. Annual runoff and sediment load in the Xihanshui catchment both exhibited significant decreasing trends (p < 0.05) with a significant mutation in 1993 (p < 0.05). The average annual runoff in the change period (1994–2016) decreased by 49.58% and annual sediment load displayed a substantial decline with a reduction of 77.77% in comparison with the reference period (1966–1993) due to climate change and intensive human activity. The power functions were satisfactory to describe annual and extreme monthly runoff–sediment relationships, whereas the monthly runoff–sediment relationship and extreme monthly sediment-runoff relationship were changeable. Spatially, annual runoff–sediment relationship alteration could be partly attributed to sediment load changes in the upstream area and runoff variations in the downstream region. Three quantitative methods revealed that the main driver for significant reductions of annual runoff and sediment load is the human activity dominated by soil and water conservation measures, while climate change only contributed 22.73%–38.99% (mean 32.07%) to the total runoff reduction and 3.39%–35.56% (mean 17.32%) to the total decrease in sediment load. |
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| Keywords: | multi-temporal scales runoff runoff–sediment relationship sediment load sediment source area Xihanshui catchment |
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