关键词: 坡面流, 坡面侵蚀, 动力过程, 模型研究

Abstract: On the basis of reviewing the history and present situation of the study on overland flow and hillslope processes, the author summarized the recent development in following fields—the forming mechanism, hydraulic features and models of overland flow, the processes and models of hillslope evolution. It shows that, with theories and methods of geomorphology, hydrology, hydraulics and sediment movement mechanism, to study the erosion dynamic processes and its critical conditions is one of the current frontiers of overland flow and hillslope processes. Finally, the problems and futures of the researches in these fields were put forward.In Addition, some new ideas about the hydrological factors of the overland flow and the formation mechanism of small erosion holes on the slope were also given in this paper. It shows that critical Flow Reynolds Number (R_e) and Energy Per Unit Section (E_s) can be main critical hydraulic parameters to determine whether rill flow appears; the critical Flow Kinetic Energy (E_v) and Critical Shear Stress(τ_c) can be secondary parameters; the critical Froude Number (F_r)≥1 can be one of the essential conditions for the rill flow generation. It is also found that all of the flow potential energy are transformed into the kinetic energy. And water flow is so thin that rainsplash becomes very severe in the joint between trough of rolling wave and slope surface, where the small erosion holes appear firstly.

Key words: overland flow, hillslope processes, overland flow velocity, rill erosion model