小流域侵蚀产沙空间分布的模拟试验研究

Study on Spatial Distribution of Erosion Yield in a Small Watershed by Simulation Experiment

小流域是黄土高原水土流失综合治理的基本单元，研究其侵蚀产沙的空间分布，对于水土保持措施的实施，有着重要的意义。通过模拟试验，首次将REE示踪法引入到小流域侵蚀产沙的空间分布研究。试验结果表明：小流域侵蚀产沙的空间分布与小流域的沟道发育有着本质的联系。在流域发育的初始阶段，下切侵蚀是一种主要的侵蚀方式，侵蚀强烈部位从沟口向沟内延伸；随后河道侵蚀量减少，而溯源区和坡面产沙量增高。试验结果同时表明了REE多元素示踪法可比较满意地解决小流域侵蚀产沙的空间分布问题，是一种研究小流域泥沙来源的有效方法。

A small watershed is the basic unit of comprehensively controlling soil and water loss in the Loess Plateatl. It is very important for designing soil and water conservation measures and preventing soil and water loss to study its spatlal distrlbution of erosion yield. In this paper, the REE tracer method was flrstly applied on spatial distribution of erosion yield in a small watershed by simulation experiment. The results showed:there are an essentlal connection between spatial distributlon of erosion and developing of gullies in a small watershed. At the first stage of watershed developing, gully Cutting erosion was a main eroslve way, and the part of erosive intensity extended from lower course to upper course. Then .with the developing of gullies, there existed a trend that gully erosive intensity gradually decreased and erosive intensity of slope and headward erosion nrea gradually incrensed. The results also showed that REE multi - element tracer could perfectly solve the problem of spatial distribution of erosion in a small watershed, and REE tracer method was an effective method for studying sediment sourcein a small watershed.