不同坡面单元人工降雨产流试验与分析

土壤前期含水率、坡度、雨强和植被是降雨产流过程的重要影响因子.目前,利用人工降雨产流试验对降雨产流机制的研究主要集中在黄土高原干旱地区和南方湿润地区,关注华北平原地区的较少,为探究不同因素对华北地区降雨产流过程的影响,利用河北工程大学临洺关校区人工模拟降雨试验平台,分析了不同降雨情景下地表径流产流响应的差异性.结果 表明:产流起始时间随土壤前期含水率、坡度和雨强的增大而减小,且受土壤前期含水率的影响更显著,产流量随时间变化呈现先增加后平稳的趋势;裸地坡产流起始时间小于自然草地,在起始产流至达到稳定临界点的时段内,裸地和草地坡产流量与产流历时呈现对数关系;累积产流量与降雨历时呈线性函数分布,拟合优度均在0.9以上.相较植被和坡度而言,土壤前期含水率和雨强是影响试验单元产流最重要的两大因素.通过上述不同情景、不同因素的试验差异分析研究,以期为构建适用于华北平原的产汇流模式提供理论依据和数据支撑.

Experiment and Analysis of Rainfall Yield in Different Slope Units

Antecedent soil moisture, slope, rainfall intensity and vegetation are important factors on rainfall runoff process. In order to investigate the influence of different factors on the process of rainfall runoff, the surface runoff yield responses in different scenarios were simulated and analyzed through the experimental plot of artificial rainfall runoff on the Linmingguan campus of Hebei University of Engineering. It is concluded that: the initial time of runoff yield delays with increasing antecedent soil moisture, rainfall intensity and slope. The delay response is more significant to the antecedent soil moisture. Besides, the runoff yield volume increases as the artificial rainfall continues, and becomes steady gradually. The initial time of runoff on bare soil is earlier than that on natural grassland. Log function is fit to describe the relationship between the runoff volume and runoff duration as the runoff yield is attaining to the critical stability point. Furthermore, the cumulative runoff yield and rainfall are linear, of which the goodness of fit is above 0.9. This study aims to provide a reference to rainfall runoff pattern in the piedmont unsaturated zone of Hebei Plain.