GEOGRAPHICAL RESEARCH ›› 2009, Vol. 28 ›› Issue (3): 583-591.doi: 10.11821/yj2009030003

• Earth Surface Processes • Previous Articles     Next Articles

Study on the runoff generation capacity of slope surface and its influencing factors in a hilly loess region on the Loess Plateau

FANG Hai-yan1, CAI Qiang-guo1, LI Qiu-yan2   

  1. 1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    2. College of Water Conservancy and Civil Engineering, China Agricultural University, Beijing 100083, China
  • Received:2008-09-14 Revised:2009-03-18 Online:2009-05-25 Published:2009-05-25
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Slope surface is the most important sediment source area in basins on the Loess Plateau, and it is of great significance to the study on runoff generation capacity influenced by rainfall and slope surface characteristics. Seven runoff plots, located on the shady side of Tuanshangou Gully in hilly loess region on the Loess Plateau, were selected in this paper, using nine years of dataset, and the changing rule of runoff coefficients on different slope surfaces were studied in the context of different rainfall regimes. According to rainfall depth, rainfall duration, and rainfall intensity, the nine years of rainfalls in the study area were classified into three regimes through K-means clustering in SPSS software, i.e. rainfall regime A with high rainfall intensity, short duration and high occurring frequency, rainfall regime C with low rainfall intensity, long duration and low occurring frequency, and B the medium. Studies found that, for each of the study plots, runoff coefficients induced by rainfall regime A were the highest, and those induced by rainfall regime C the lowest. However, scale effect on runoff induced by rainfall regime A was the least, and that induced by rainfall regime C the largest. In slope Mao region, given the same slope degree, runoff coefficients firstly increased, and then decreased, and a peak value occurred for rainfall regime A on the slope surfaces of Nos.2-4 plots, however, runoff coefficients increased with increasing slope lengths for rainfall regimes B and C. For the slope surfaces of Nos.1, 4, and 5 plots that have the same slope length, under all the three rainfall regimes, runoff coefficients increased with increasing slope gradients. Entering gully slope area, runoff plot No.6 had the lowest coefficient in the condition of rainfall regime A and those induced with rainfall regimes B and C had higher values. For entire slope surface of No.7 plot, runoff coefficients induced by the three rainfall regimes had the medium values.

Key words: hilly loess region on the Loess Plateau, rainfall regime, slope surface, runoff coefficient, scale effect