峰丛洼地坡面流径流过程——以丫吉试验场为例

Runoff Process of Overland Flow in Peak Cluster Depression:The Case from a Karst Experiment Site

选取裸露型和土壤植被覆盖型两种峰丛洼地地貌结构,通过降雨量、pH、电导率(Ec)、CO2分压和流量的过程线来分析降雨中详细的产流过程。裸露性坡地因包气带结构简单仅存在局部的超渗产流和表层岩溶带的回归流,水化学性质较稳定;有土壤植被覆盖的坡地的产流过程可以分为3个阶段:补偿阶段(可出现超渗产流)、饱和径流阶段、稳定阶段,补偿阶段仅在降雨强度大于入渗强度时可产生坡面流,饱和径流阶段坡面流流量与降雨强度成正比,稳定阶段坡面流流量趋于稳定,不随雨强的变化而变化,坡面流的水化学性质变化剧烈,pH、电导率(Ec)、CO2分压基本上同步变化,水温(T)在降雨前期变化规律不明显,后期与pH、Ec等呈相反变化。

The peak cluster depression areas with bare rock and soil-vegetation separately covered were selected to analyze their runoff yield processes by using the curves of rainfall, PH, Ec, PCO2 and hydrographs. The results show that due to simple structure of the bare rock, there are only some runoff yield in excess of infiltration and return flow from epikarst. The hydrochemical characteristics are stable. The runoff of the overland with soil-vegetation covered can be divided into 3 stages： Compensatory stage, saturation runoff stage and steady stage. At the compensatory stage, overland flow occurs when rain intensity is stronger than infiltration; the saturation flow is positive correlation with rain intensity; the rate of overland flow tend to be stable at the steady stage without relationship with rain intensity. The hydrochemistry fluctuates strongly and PH, Ec, PCO2 changes uniformly. The variety of temperature is disorder in antecedent rainfall and contrary to PH, Ec in later stage.