四川丘陵区常规耕作制下紫色土径流发生特征及其表面流数值模拟

设计了一种简单的壤中流观测系统来研究不同降雨产流事件的过程,结果表明：(1) 在小雨时,只有表面径流发生;而且,当雨前土壤较干燥,降雨初期雨强陡然增大的情况下,表面产流峰有特别明显滞后现象,这是由于临时相对不透水表层形成之故。(2) 在暴雨和大暴雨时,表面径流和壤中流都有发生;壤中流比表面径流滞后更明显;壤中流在雨后的产流历时与降雨无关;在大暴雨时,耕作层的壤中流水位过程曲线与表面径流相似,说明耕作层的大孔隙和管流明显。(3) 在小雨和暴雨时,表面流由超渗产流机制形成;在大暴雨时,表面流主要由饱和超渗产流机制形成,只有少部分回归流。(4) 表面径流的数值模拟能揭示表面产流的一般趋势,而且有一定的有效性,通过调整模拟参数,能使模拟效果更佳。

Characteristics of runoff generation and its numerical simulation of surface flow in hilly area with purple soil under convetional tillage systems

A throughflow collection system is established to investigate the process of runoff generation both for surface flow and subsurface flow. The results show that: 1.under the condition of flurry,surface runoff will be generated and the lag phenomenon may happen to the flow peak if the soil is dry before the rain; 2.both surface runoff and throughflow commence under the condition of rainstorm and downpour; 3. under the condition of flurry and rainstorm,surface runoff is controlled primarily by infiltration-excess runoff mechanism. The numerical simulation can be used to explore the general tendency of the surface runoff.