室内模拟降雨条件下径流侵蚀产沙试验研究

Experimental Study on Law of Runoff-Erosion-Sediment Yield under Indoor Simulated Rainfall Condition

降雨及其产生的径流是引起黄土高原土壤侵蚀的主要动力,开展黄土区降雨产流产沙过程研究可为土壤侵蚀过程模型研发奠定基础,为水土保持与生态建设提供重要科学依据。利用室内模拟降雨试验,研究了不同植被格局条件下的坡面侵蚀产沙、径流、入渗规律及相关关系。研究结果表明,裸坡坡面下,雨强是影响径流的主要因素,径流贡献率为87%;坡度是影响产沙的主要因素,产沙贡献率为76%;在大雨强或陡坡条件下,这种趋势更加明显。模拟降雨条件下,坡面含水量以坡面中下部最大,坡面中部居中,坡面上部最小。坡面植被覆盖对侵蚀产沙的影响大于坡度因素的影响;相同覆盖度条件下,植被空间位置对水沙调控作用大小顺序依次为:坡底>坡中>坡顶。随植被覆盖率的增加,径流总量呈幂函数减小趋势,产沙总量和径流含沙量呈指数函数减小趋势,植被对水沙调控作用逐渐增强。本文研究成果对于深入理解流域径流产流产沙过程具有重要意义,可为相关的模型研究提供可靠的试验支持。

Rainfall and runoff are the main dynamic factors which cause soil erosion on the Loess Plateau.Research on processes of rainfall,runoff and sediment yield can promote the development of soil erosion process-based model,and provide important scientific basis for soil and water conservation,and ecology construction on loess region.The rules of rainfall and runoff erosion,sediment yield,infiltration and the correlation among each other were studied under different vegetation patterns by using indoor simulated rainfall experiments.The results showed that rainfall intensity was the main factor affecting runoff generation,with a contribution ratio of runoff generation of 87%,while slope gradient was the main factor affecting sediment yield,with a contribution ratio of sediment yield of 76%,which were more obvious in strong rainfall or on steep slope.Under simulated rainfall condition,the moisture content on slope was in the following order： middle-lower slopemiddle slopeupper slope.Vegetation coverage had more influence on runoff and sediment yield than slope gradient.Vegetation distributed in the lower slope conserved soil better than that in the upper and middle slopes under the same vegetation coverage condition.With the increase of vegetation coverage,runoff volume decreased within the power function distribution range,the total sediment yield and sediment concentration decrease within the exponential function distribution range,and the effectiveness of vegetation regulating on runoff and sediment yield were strengthened gradually.The results were significantly meaningful for understanding the rainfall and runoff erosion and sedimented yield process in watershed,and could provide reliable experimental support for related researches on soil erosion model.