Journal of Geographical Sciences ›› 2019, Vol. 29 ›› Issue (6): 1001-1020.doi: 10.1007/s11442-019-1641-y

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Sediment load change with erosion processes under simulated rainfall events

Liying SUN1,2, Haiyan FANG2, Qiangguo CAI2,6, Xihua YANG3, Jijun HE4, John L. ZHOU5, Xunming WANG2   

  1. 1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, CAS&MWR, Yangling 712100, Shaanxi, China
    2. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    3. New South Wales Office of Environment and Heritage, PO Box 644, Parramatta, NSW 2124, Australia
    4. Base of the State Laboratory of Urban Environmental Processes and Digital Modeling, Capital Normal University, Beijing 100048, China
    5. School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia
    6. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-06-19 Accepted:2018-07-12 Online:2019-06-25 Published:2019-07-25
  • About author:

    Author: Sun Liying (1978-), Associate Professor, specialized in soil erosion and risk analysis. E-mail: sunliying@igsnrr.ac.cn

  • Supported by:
    National Natural Science Foundation of China, No.41471229;The Open Project Fund from the State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, No.A314021402-1601;National Key Research and Development Program of China, No.2016YFA0601900

Abstract:

It is of great significance to quantify sediment load changing with erosion processes for improving the precision of soil loss prediction. Indoor rainfall experiments were conducted in 2 rainfall intensities (90 mm·h-1 and 120 mm·h-1), four slope gradients (17.60%, 26.80%, 36.40%, 46.60%) and 2 slope lengths (5 m, 10 m). Erosion processes are divided into five stages. Results show that sediment yield is mainly sourced from rill erosion, contributing from 54.60% to 95.70% and the duration of which is extended by slope gradients. Sediment load and sediment concentration are significantly different along erosion stages, with the highest values in rill development stage (SIV). Surface flow velocities (interrill and rill) demonstrate less significant differences along erosion stages. Rainfall intensity increases sediment load in all stages, with up to 12.0 times higher when changing from 90 to 120 mm·h-1. There is an increasing trend for sediment load and sediment concentration with the rising slope gradient, however, fluctuations existed with the lowest values on 26.80% and 36.40%, respectively, among different treatments. The slope gradient effects are enhanced by rainfall intensity and slope length. Results from this study are important for validating and improving hillslope erosion modelling at each erosion stage.

Key words: rainfall simulation, erosion experiments, rill erosion, interrill erosion, sediment load