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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >In-situ assessment of the spatial arrangement of step-pool units on eroded rills
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In-situ assessment of the spatial arrangement of step-pool units on eroded rills

机译：原位评估侵蚀桁架上阶梯池单元的空间安排

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摘要

Rills are generated on homogeneous hillslopes by the action of different discharges and evolve morphologically over short timescales due to a strong interaction between the flow and bed morphology. Such an interaction generates a reconfiguration of the bed geometry. Previous works suggest that bed geometry is often characterized by alternation between pools and flat reaches (steps). Each step-pool unit may contribute to hydraulic resistance and affects flow behaviour. The objectives of this work are (i) to assess different (innovative) techniques for the in-situ assessment of rill bed geometry, (ii) to use these techniques to assess the geometry of eroded rills in situ in order to determine the spatial arrangement in the bed macro-scale roughness and (iii) finally to analyse the role of slope and discharge as driving factors associated with the development of these macroforms. Roughly rectilinear, long rills were formed in the field as a result of combining different slope and discharges. Photogrammetry provided detailed digital elevation models (DEMs) before and after the experiments. The rills were morphologically characterized from the DEMs. In each rill, the presence of step-pools was identified from long profiles according mainly to morphological criteria published elsewhere, but with ad hoc critical threshold values more appropriate for small eroded channels. The minimum slope required for the development of step-pool units seems to be somewhere between 5 and 15%. Discharge seems to affect pool size or roughness amplitude. There does not seem to be a clear step-pool periodicity. However, external factors could have affected the normal growth and alternation of these structures. Identification of steps and pools from longitudinal elevation profiles can be objectively accomplished using a series of geometric rules originally proposed for rivers and large channels, and adapted to rills. (c) 2019 John Wiley & Sons, Ltd.
机译：由于流动和床形态的强烈相互作用，通过不同的排放的作用，在均匀的山坡上产生橄榄植物在同质的山坡上产生，并在短时间内演变。这种交互产生床几何形状的重新配置。以前的作品表明，床几何通常是池与平面到达（步骤）之间的交替的特征。每个阶梯单元可以有助于液压阻力并影响流动行为。这项工作的目标是（i）评估用于梯级床几何的原位评估的不同（创新）技术，（ii）使用这些技术来评估原位侵蚀瑞尔的几何形状，以便确定空间排列在床上宏观规模粗糙度和（iii）最后分析斜坡和放电的作用作为与这些大甲染色型开发相关的驱动因子。由于组合不同的坡度和放电，在现场中形成大致直线，长浆。摄影测量在实验之前和之后提供了详细的数字高度模型（DEM）。橄榄植物在一起的形态学，从事DEM。在每个盗贼中，阶梯池的存在是从别处发布的形态标准的长篇轮廓识别，但是具有临时临界阈值值更适合小侵蚀通道。阶梯单元开发所需的最小坡度似乎在5％至15％之间。放电似乎影响池大小或粗糙度幅度。似乎没有明确的阶梯池周期性。然而，外部因素可能影响了这些结构的正常增长和交替。可以使用最初提出的河流和大型通道的一系列几何规则来识别来自纵向高度剖面的步骤和池，并适合瑞尔。 （c）2019 John Wiley＆Sons，Ltd。

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