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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Relation between flow, surface-layer armoring and sediment transport in gravel-bed rivers
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Relation between flow, surface-layer armoring and sediment transport in gravel-bed rivers

机译：砾石河床流量，表层装甲与输沙量的关系

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摘要

This study investigates trends in bed surface and substrate grain sizes in relation to reach-scale hydraulics using data from more than 100 gravel-bed stream reaches in Colorado and Utah. Collocated measurements of surface and substrate sediment, bankfull channel geometry and channel slope are used to examine relations between reach-average shear stress and bed sediment grain size. Slopes at the study sites range from 0.0003 to 0.07; bankfull depths range from 0.2 to 5 m and bankfull widths range from 2 to 200 m. The data show that there is much less variation in the median grain size of the substrate, D-50s, than there is in the median grain size of the surface, D-50; the ratio of D-50 to D-50s thus decreases from about four in headwater reaches with high shear stress to less than two in downstream reaches with low shear stress. Similar trends are observed in an independent data set obtained from measurements in gravel-bed streams in Idaho. A conceptual quantitative model is developed on the basis of these observations to track differences in bed load transport through an idealized stream system. The results of the transport model suggest that downstream trends in total bed load flux may vary appreciably, depending on the assumed relation between surface and substrate grain sizes. Copyright (C) 2007 John Wiley & Sons, Ltd.
机译：这项研究使用来自科罗拉多州和犹他州的100多个砾石床水流的数据，调查了河床表面和基质粒径相对于河床规模水力的趋势。地表沉积物和基底沉积物，河床满槽的几何形状和河道坡度的并置测量用于检验平均剪切应力与床层沉积物粒径之间的关系。研究地点的坡度为0.0003至0.07;堤岸深度范围为0.2至5 m，堤岸宽度范围为2至200 m。数据显示，基材的中值晶粒尺寸D-50s的变化要比表面的中值晶粒尺寸D-50的变化小得多。因此，D-50与D-50的比率从高剪切应力的上游水域下降到约4，而下游的低剪切应力则小于2。从爱达荷州砾石床流的测量获得的独立数据集中，观察到了类似的趋势。在这些观察的基础上开发了概念性的定量模型，以跟踪通过理想流系统的床层负荷输送中的差异。传输模型的结果表明，总床负荷通量的下游趋势可能会明显变化，这取决于表面和基材晶粒尺寸之间的假定关系。版权所有（C）2007 John Wiley＆Sons，Ltd.

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