Acta Geographica Sinica ›› 2019, Vol. 74 ›› Issue (5): 962-974.doi: 10.11821/dlxb201905010

• Climate Change and Surface Processes • Previous Articles     Next Articles

Quantifying the contributions of sand layer characteristic to variations of runoff and sediment yields from sand-covered loess slopes during simulated rainfall

CAO Xiaojuan1,5,XIE Linyu2,ZHANG Fengbao1,3(),YANG Mingyi1,3,LI Zhanbin4   

  1. 1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, CAS and Ministry of Water Resources, Yangling 712100, Shaanxi China
    2. Xi’an Workstation of Soil and Water Conservation, Xi’an 710018, China;
    3. Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China;
    4. Institute of Water Resources and Hydro-electric Engineering, Xi’an University of Technology, Xi’an 710048, China;
    5. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-07-06 Revised:2019-02-18 Online:2019-05-25 Published:2019-05-24
  • Contact: ZHANG Fengbao
  • Supported by:
    National Key Research and Development Program of China, No.2016YFC0402407;National Natural Science Foundation of China(41371283);National Natural Science Foundation of China(41877080)


Loess slopes covered with aeolian sand are unique geomorphic features in the wind-water erosion crisscross region on the Chinese Loess Plateau. On these loess slopes, runoff and sediment production patterns are unique and complex and the thickness of covering sand and its interaction with other factors may largely interfere soil erosional responses. Therefore, quantifying the variations of runoff and sediment yields and assessing the possible factors are of great importance to understand the erosion mechanism in such unique landscapes. To quantify the effects of sand layer thickness and sand size composition on runoff generation and sediment yield, sand-covered loess slopes with 15° were subject to simulated rainfall events (intensity 1.5 mm/min) in this study. Sand layers of three different thicknesses, 2 cm, 5 cm and 10 cm, were respectively placed on loess surface. For each sand thickness, there were five kinds of compositions, i.e. 100% sand diameter ≤ 0.25 mm, 75% sand diameter ≤ 0.25 mm + 25% sand diameter > 0.25 mm, 50% sand diameter ≤ 0.25 mm + 50% sand diameter > 0.25 mm, untreated sand, and 100% sand diameter > 0.25 mm. Our results show that as sand thickness increased, it prolonged initiation time of runoff, reduced runoff yield, increased sediment yield and enhanced the variability in runoff and soil loss rates during rainfall. Our findings also indicate that with coarser sand, the total runoff loss tended to increase even though the initiation time of runoff and sediment yield was not obviously changed. The sand layer thickness, sand size composition, and their interactions respectively contributed 68.03%, 15.77%, and 3.85% to the variation of initiation time of runoff (p < 0.05), respectively. For the runoff production, the sand layer thickness can explain 23.89% to 52.22% of the variation of runoff rates during a 15-min rainfall sub-rainfall, and 41.10% to 48.94% of total runoff loss for different rainfall durations. For the sediment production, the sand layer thickness can explain 29.19% to 62.01% of the variation of soil loss rates during a 15-min rainfall sub-rainfall, and 13.53% to 30.31% the total sediment yield for different rainfall durations. Moreover, the sand size composition had less impact on runoff and sediment yields than the thickness of the sand layers. Their combined effects were significant during the early and intermediate stages (p < 0.05), and contributed to 13.12%-26.62% of runoff loss and 3.22%-43.12% of sediment yield. Overall our observations suggest that runoff and sediment generation on sand-covered loess slopes were mainly affected by the sand layer thickness rather than sand size composition, and their combined effects also varied as erosion proceeded.

Key words: sand layer thickness, particle size composition, runoff, sediment, contribution rate