Mechanism of rill initiation in sandy soils
1999
Khan, F. | Afzal, M. (NWFP Agricultural Univ., Peshawar (Pakistan). Dept. of Soil Science)
Experiment were conducted to investigate the mechanism of rill initiation under varying steady and uniform flow conditions in a laboratory flume at different slope conditions. It was found that soil particle diameter and slope had an important influence on critical flow for rill initiation, while the critical velocity for rill initiation was almost constant for the range of the slope degree tested. Comparing the critical velocity with the critical shear stress for rill initiation, the critical shear stress is slope dependent while the critical velocity is slope independent. Therefore , critical velocity can be used as an important parameter for rill initiation. Rill initiation can best be explained as a result of a balance between the erosive power of the flow and the erosion resistance of the bed material and can be expressed by the empirical equation KD Vc2/2=(ksf cos chita-ksg sin chita) d-3. The derived empirical relationships can contribute to the development of physically based erosion models.
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