【摘要】 为研究长江三峡花岗岩地区优先流对渗流和地表径流的影响,以长江三峡地区曲溪小流域作为试验用地,选择适当的土壤剖面作为观测剖面。采用自记流量计测量了优先流、渗流和降雨过程。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,分析了优先流和渗流、地表径流之间的关系。结果表明,在同等降雨条件下,优先流晚于渗流出现,早于渗流停止。优先流流量在剖面渗流总量中的比例可达2.40%～48.72%。优先流水分通量最大可达剖面渗流水分通量的17200倍,会在很大程度上增加土壤水分运动通量。在同场降雨中,优先流的介入使得渗流流量峰值出现时间提前。优先流的出现导致地表径流峰值出现时间延迟,洪水历时过程延长。前期影响雨量及产流次雨量较小时,优先流与地表径流之间相互影响较大。更多还原

【Abstract】 To study the effects of preferential flow on infiltrated flow and surface runoff in the granite area of the Three Gorges,Yangtze River,China,a soil profile that is not seriously disturbed by human activities was selected in the Quxi watershed of the area as a field experimental site.Preferential flow,infiltrated flow and rainfall were measured by an automatic flowmeter.Surface runoff was measured by an automatic gauge and a thin triangle weir vertically installed at the outlet of the watershed.The relationships among preferential flow,infiltrated flow and surface runoff were analyzed.Results showed that during the same rainfall,preferential flow appeared later and stopped earlier than infiltrated flow.The percentage of preferential flow flux over the total infiltrated water can reach 2.40%～48.72%.The maximal preferential flow flux can reach 17 200 times of that of infiltrated flow,which could increase soil water flux to a great extent.In the same rainfall,the intervention of preferential flow advanced the appearance of peak infiltrated flow,postponed the appearance of peak surface runoff and prolonged the duration of surface runoff.When the amounts of current rainfall and antecedent influenced rainfall are smaller,preferential flow and surface runoff influenced each other more greatly.更多还原