三峡库区小流域降雨入渗和产流产沙特征试验研究

Rainfall Infiltration and Characteristics of Runoff and Sediment Yield in Small Watershed of Three Gorges Reservoir Area

三峡库区暴雨集中,历时短,强度大,是造成土壤侵蚀的重要因素。为开展对三峡库区小流域降雨入渗和产流产沙特征研究,通过建立三峡库区小流域微缩模型,分别实施降雨强度为60,90,120 mm/h的3场人工模拟降雨,对小流域模型降雨入渗规律和径流侵蚀过程进行了分析。研究结果表明:径流量均随降雨强度的增加而增加,而降雨强度增加入渗的作用仅在一定范围内是有效的;随着降雨的进行,产流强度和入渗率都趋于稳定状态,入渗率服从对数函数规律,产流强度呈幂函数变化;3场降雨中累计产沙量和累计径流量的关系均满足幂函数形式,含沙量和侵蚀量之间呈较好的线性关系。该研究成果可为这一区域的水土流失防治提供重要的科学依据。

In Three Gorges reservoir area,concentrated rainstorm with short duration and high intensity is an important factor causing soil erosion. In the aim of investigating rainfall infiltration and characteristics of runoff and sediment yield in small watershed of Three Gorges reservoir area,we establish a miniature model for the area and simulate rainfall in the presence of different rainfall intensities（ 60,90,120 mm / h） to analyze rainfall infiltration of small watershed erosion and runoff process characteristics. Research results show that ： 1） runoff yield increases with rainfall intensity,and the impact of rainfall intensity on increase of infiltration is effective only within a certain range; 2） infiltration rate and runoff yield intensity gradually tend to be stable,infiltration rate is in agreement with law of logarithmic function,whereas runoff yield intensity varies according to power function; 3） relationship between cumulative sediment yield and cumulative runoff in the three rainfalls can be fitted by power function,and there is a good linear relationship between sediment concentration and erosion yield. The results provide important scientific basis for the prevention and control of soil and water loss in the area.