Effects of intra-storm variations in rainfall intensity on interrill runoff and erosion
Effects of intra-storm variations in rainfall intensity on interrill runoff and erosion
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DOI：
10.1016/j.catena.2006.03.002
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发表时间：
2006-08
期刊：
影响因子：
6.2
通讯作者：
A. Parsons;P. Stone
中科院分区：
文献类型：
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作者：
A. Parsons;P. Stone
在实验室水槽中，将五场模拟暴雨应用于三种不同的土壤上，每种暴雨具有不同的降雨强度模式，但都向土壤表面提供相同的总动能。暴雨类型为：恒定雨强、增大强度、减小强度、增大后减小、减小后增大。这三种土壤是：粘壤土、沙壤土和沙质土。在三种土壤类型中，没有观察到一致的总径流差异。然而，在侵蚀沉积物的数量和粒度分布上观察到了一致的差异。尤其是等强度风暴产生的土壤流失量平均为变强度风暴的75%，其侵蚀泥沙的粘粒含量低于变强度风暴。与侵蚀泥沙的数量和粒度分布的差异相比，飞溅泥沙的差异要小得多。人们普遍认为细沟侵蚀率随降雨强度的2次方而变化，但这一关系是从一系列降雨强度的实验中获得的，但在每次实验中降雨强度都是恒定的。这里报道的实验，在每个实验中使用不同的降雨强度进行，表明指数为2.55。实验表明，假设给定的降雨强度在给定的时间内落在给定的土壤上会导致给定的径流量和侵蚀量，这种假设是不合理的。它们指出，需要更好地了解细沟间泥沙的剥离和迁移过程，以便成功地模拟降雨随时间变化的侵蚀情况。
Five simulated rainstorms, each with a different rainfall intensity pattern but all delivering the same total kinetic energy to the soil surface, were applied to three different soils in a laboratory flume. The storm patterns were: constant rainfall intensity, increasing intensity, decreasing intensity, increasing then decreasing intensity and decreasing then increasing intensity. The three soils were: a clay loam, a sandy loam and a sandy soil. No differences in total runoff were observed that were consistent across the three soil types. However, consistent differences were observed in the amount and size distribution of the eroded sediment. In particular, the constant-intensity storm yielded an average soil loss of 75% of the varying-intensity storms, and the eroded sediment from the constant-intensity storms had a lower clay content than that from the varying-intensity storms. In contrast to the differences in amount and size distribution of eroded sediment, splashed sediment exhibited much smaller differences. Interrill erosion rates are widely assumed to vary with rainfall intensity to the power 2, but this relationship has been obtained from experiments over a range of rainfall intensities, but in which rainfall intensity has been constant in each experiment. The experiments reported here, undertaken using variable rainfall intensity within each experiment, indicates an exponent of 2.55. The experiments demonstrate that the assumption that a given rainfall intensity falling on a given soil for a given amount of time will result in a given amount of runoff and erosion is unsound. They point to the need for a greater understanding of the processes of interrill sediment detachment and transport in order to model successfully erosion under temporally varying rainfall.