ABSTRACT

Overland flow occurs on a land surface, making a sheet flow without any flow concentration. Under these conditions, cultivated semi-arid hillslopes experience inter-rill erosion. One objective of this study was to evaluate the hydraulic resistance caused by semi-arid crops and shrubs in two slopes’ field conditions, and the other was to learen more about the overland flow governed by Froude number. To achieve these targets, a set of rainfall simulations was performed on two slope gradients, of 4.9% and 8.9%, covered by shrubs and semi-arid crops. On these two semi-arid hillslopes, exfiltration occurred, which added flow from subsurface water by seepage. We show, for the first time, that for overland flow with Reynolds number from 1 to 100 in different crops and native Brazilian shrub, hydraulic resistance is more strongly correlated with Froude number than with Reynolds number, as were the vegetal force drag and the soil detachment rate.

摘要

地表流发生在陆地表面，形成没有任何流量集中的片状流。在这些条件下，耕作的半干旱山坡会经历细沟间侵蚀。本研究的一个目的是评估两个斜坡田间条件下半干旱作物和灌木引起的水力阻力，另一个目的是更多地了解由弗劳德数支配的地表水流。为了实现这些目标，在灌木和半干旱作物覆盖的两个坡度坡度上进行了一组降雨模拟，坡度分别为 4.9% 和 8.9%。在这两个半干旱的山坡上，发生了渗漏，通过渗流增加了地下水的流量。我们首次表明，对于不同作物和巴西本土灌木中雷诺数从 1 到 100 的地表流，