细沟形态演变对坡面水沙过程的影响

为探明细沟形态演变对坡面产流产沙的互反馈作用，采用室内模拟降雨和三维地形扫描等手段对细沟形态演变中的水沙变化过程进行了研究。试验分析了黄土在不同雨强（66 mm/h、94 mm/h和127 mm/h）条件下，不同细沟发育阶段的水沙过程变化规律。结果表明，黄土细沟形态演变过程对产沙的影响较大，而对产流的影响较弱。径流量的变化过程主要取决于土体透水性、土壤的结皮作用以及产流方式，坡面产流量有先增大后减小最后趋于平稳的趋势；产沙量的变化过程与细沟发育进程有明显的对应关系，尤其是坡面地貌信息熵与产沙量和侵蚀速率的相关系数分别达到0.954和0.916，细沟的出现会加剧侵蚀，使含沙量明显增加；不同雨强下坡面产沙的变化规律基本相同，细沟沟网稳定后的产沙量与降雨强度呈正相关关系。

Rill morphology evolution and runoff and sediment yielding processes

In order to investigate the mutual feedback effects of rill morphology evolution on runoff and sediment, variation characteristics of runoff and sediment during the evolution of rill morphology were studied. In the current work, an indoor soil bin rainfall simulation experiment was performed using a 3-D terrain scanning method. Loessial soil was analyzed under rainfall intensities of 66 mm/h, 94 mm/h, and 127 mm/h. Results showed that the evolution of rill morphology had a profound effect on sediment yield, but the impact on runoff was not obvious. The variation in runoff depended mainly on infiltration conditions and crust effect of soil and patterns of runoff production. The runoff production on the slope had a tendency to first increase and then decrease before finally reaching stability. There was an obvious relationship between rill morphology evolution and sediment yield; the correlation coefficients of geomorphologic comentropy and soil loss with erosion rate were 0.954 and 0.916, respectively. The emergence of rills was found to aggravate the erosion, resulting in a significant increase in sediment concentration. The variation in sediment yield in rainfall of different intensities was basically the same. The more intense the rainfall, the higher sediment concentration after the rill network became stable.