长江三峡花岗岩坡面林地优先流与地表径流关系

为研究优先流与地表径流的关系,在长江三峡花岗岩坡面,选择了一受人为活动影响较小的天然次生马尾松林地作为试验场地。采用自记流量计记录优先流过程,在小流域出口处设置90°薄壁三角堰和水位计记录了地表径流过程,并对不同层次土壤物理性质进行了测定。结果表明,优先流流量主要决定于产流次雨量及前期影响雨量。优先流峰值总是晚于地表径流峰值出现,从优先流与地表径流峰值出现时间的差异看,优先流的出现使得地表径流峰值出现时间推迟,历时过程延长。当优先流与地表径流流量过程线为双峰时,二者线性关系不明显。当优先流与地表径流流量过程线均为单峰时,二者存在一定的线性关系,其线性关系随着产流次雨量及前期影响雨量的不同而有所差异

Relationship Between Preferential Flow and Surface Runoff in Slope of Granite Region of Three Gorges in Yangtze River

For studying the relationship between preferential flow and surface runoff, a natural second Chinese pine (Pinus massoniana) forest in the area, which has not been heavily influenced by people, is selected as an experiment site. The process of preferential flow has been recorded by an automatic flowmeter during the time of the experiment. The soil physical properties have also been determined at the same time. The result shows that the discharge of the preferential flow is mainly influenced by the precipitation and the ante~precipitation. The appearance of the preferential flow peak is later than the peak of the surface runoff. The preferential flow defers the appearance of the peak of the surface runoff and prolongs the surface runoff duration. It is not obvious that the preferential flow appears linear relationship with the surface runoff when both the preferential flow and the surface runoff appear two peaks at the same precipitation. On the contrary, the linear relationship between the preferential flow and the surface runoff is marked while both of them have one peak, and it changes with the variation of precipitation and ante-precipitation.