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This article in SSSAJ

  1. Vol. 73 No. 4, p. 1291-1297
    Received: Apr 29, 2008

    * Corresponding author(s): ghzhang@bnu.edu.cn


Sediment Transport and Soil Detachment on Steep Slopes: I. Transport Capacity Estimation

  1. Guang-hui Zhang *ab,
  2. Yu-mei Liub,
  3. Yan-feng Hanb and
  4. X. C. Zhangc
  1. a State Key Lab. of Earth Surface Processes and Resource Ecology
    b School of Geography, Beijing Normal Univ., Beijing, 100875, China
    c USDA-ARS Grazinglands Research Lab., El Reno, OK 73036


Precise estimation of sediment transport capacity (T c) is critical to the development of physically based erosion models. Few data are available for estimating T c on steep slopes. The objectives of this study were to evaluate the effects of unit flow discharge (q), slope gradient (S), and mean flow velocity on T c in shallow flows and to investigate the relationship between Tc and shear stress, stream power, and unit stream power on steep slopes using a 5-m-long and 0.4-m-wide nonerodible flume bed. Unit flow discharge ranged from 0.625 × 10−3 to 5 × 10−3 m2 s−1 and slope gradient from 8.8 to 46.6%. The diameter of the test riverbed sediment varied from 20 to 2000 μm, with a median diameter of 280 μm. The results showed that T c increased as a power function with discharge and slope gradient with a coefficient of Nash–Sutcliffe model efficiency (NSE) of 0.95. The influences of S on T c increased as S increased, with T c being slightly more sensitive to q than to S The T c was well predicted by shear stress (NSE = 0.97) and stream power (NSE = 0.98) but less satisfactorily by unit stream power (NSE = 0.92) for the slope range of 8.8 to 46.6%. Mean flow velocity was also a good predictor of T c (NSE = 0.95). Mean flow velocity increased as q and S increased in this study. Overall, stream power seems to be the preferred predictor for estimating T c for steep slopes; however, the predictive relationships derived in this study need to be evaluated further in eroding beds using a range of soil materials under various slopes.

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