Variations in runoff, sediment load, and their relationship for a major sediment source area of the Jialing River basin, southern China. Issue 7 (21st July 2021)

• Record Type: Journal Article
• Authors: Shao, Yiting; Mu, Xingmin; He, Yi; Chen, Kai
• Is Part Of: Hydrological processes. Volume 35:Issue 7(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-07-21
• Subjects: multi‐temporal scales -- runoff -- runoff–sediment relationship -- sediment load -- sediment source area -- Xihanshui catchment; Hydrology -- Periodicals; Hydrology -- Research -- Periodicals; Hydrologic models -- Periodicals; Hydrological forecasting -- Periodicals; 631.432
• DOI: 10.1002/hyp.14297
• Languages: English
• ISSNs: 0885-6087

Abstract

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. Abstract : The monthly runoff–sediment relationships were changeable and annual runoff–sediment relationship could be generally expressed as a power function for the study period, while extreme monthly runoff–sediment and sediment‐runoff relationships had different performances during P1 and P2. The main driver for the significant reductions of annual runoff and sediment load is the human activity dominated by soil and water conservation measures, as the contributions of climate change were only 22.73%–38.99% (mean 32.07%) and 3.39%–35.56% (mean 17.32%), respectively.