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Runoff and sediment yielding processes on red soil engineering accumulation containing gravels by a simulated rainfall experiment.

SHI Qian-hua1, WANG Wen-long1,2, GUO Ming-ming1, BAI Yun3, DENG Li-qiang4, LI Jian-ming1,5, LI Yao-lin6   

  1. (1State Key Laboratory Erosion and Dryland Farming on the Loess Plateaus, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China;  2Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China; 3College of Life Sciences, Yulin University, Yulin 719000, Shaanxi, China; 4Shandong Institute of Water Resources Research, Ji’nan 250013, China; 〖JP2〗5Department of Soil and Water Conservation, Changjiang River Scientific Research Institute , Wuhan 430010, China; 6Xifeng Soil and Water Conservation Experimental Station, Qingyang 745000, Gonsu, China)
  • Online:2015-09-18 Published:2015-09-18

Abstract: Engineering accumulation formed in production and construction projects is characterized by unique structure and complex material composition. Characteristics of soil erosion on the engineering accumulation significantly differ from those on farmland. An artificially simulated rainfall experiment was carried out to investigate the effects of rainfall intensity on the processes of runoff and sediment yielding on the engineering accumulation of different gravel contents (0%, 10%, 20% and 30%) in red soil regions. Results showed that the initial time of runoff generation decreased with increases in rainfall intensity and gravel content, the decreased amplitudes being about 48.5%-77.9% and 4.2%-34.2%, respectively. The initial time was found to be a power function of rainfall intensity. Both runoff velocity and runoff rate manifested a trend of first rising and then in a steady state with runoff duration. Rainfall intensity was found to be the main factor influencing runoff velocity and runoff rate, whereas the influence of gravel content was not significant. About 10% of gravel content was determined to be a critical value in the influence of gravel content on runoff volume. For the underlying surface of 10% gravel content, the runoff volume was least at rainfall intensity of 1.0 mm·min-1 and maximum at rainfall intensity of greater than 1.0 mm·min-1. The runoff volume increased 10%-60% with increase in rainfall intensity. Sediment concentration showed a sharp decline in first 6 min and then in a stable state in rest of time. Influence of rainfall intensity on sediment concentration decreased as gravel content increased. Gravels could reduce sediment yield significantly at rainfall intensity of greater than 1.0 mm·min-1. Sediment yield was found to be a linear function of rainfall intensity and gravel content.