典型喀斯特流域地表产流输出特征

由于喀斯特区域表层岩溶带的结构和构造表现为高度的异质性,以及大量缺失定位观测资料,使得该区域目前还没有较为完善的产汇流模型。对特定小流域地表产流输出过程的分析,有利于对流域内部各种水文过程的认识。本研究正是基于这一背景,通过对一完整自然年的地表产流输出进行分析发现,流域地表径流输出主要发生在5~10月份;受雨强和壤中流向地表径流转化过程的影响,5月份的地表径流产流输出为突发衰弱型伴有明显的迟滞效应,其他月份主要为渐进增强衰弱型,迟滞效应较5月份明显减弱;如去除5月份的影响,6~10月份流域地表径流输出量与降雨量呈显著正相关关系(p0.05,r=0.99);壤中流向地表径流径流转化具有明显的季节性差异;就全年而言,经由卡口站地表径流输出的量占全年降雨总量的23.1%。

OUTPUT CHARACTERISTICS OF SURFACE RUNOFF IN TYPICAL KARST WATERSHED

Modeling on runoff dynamics in Karst region of Southwest of China is nearly impossible due to high heterogeneity of carbonate structure and composition, and the shortage of observed data in site. It is helpful to know the different water processes through observing and analyzing the variation of flow output in a small watershed exit. Based on the background, this research has analyzed flow output in a whole calendar year. The results indicated that the flow output emerged only from May to October. With the influences of rainfall intensity and conversion process of interflow to surface runoff, the flow output broken out after several hours of rain, then faded out slowly in May. But the flow output gathered strength with rain in June to October and the lag-effect was shorter than in May. With exception of May, the relationship between rainfall and flow output amount was significant from June to October. There were seasonal variationsin conversion of interflow to surface flow, which determined the flow duration in exit of watershed. The amount of flow output accounted for approximately 23.1% of annual rainfall.