当前位置: X-MOL 学术Land Degrad. Dev. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Predicting the sediment transport capacity from flow condition and particle size in the presence of vegetation cover
Land Degradation & Development ( IF 4.7 ) Pub Date : 2020-10-18 , DOI: 10.1002/ldr.3778
Hongli Mu 1, 2 , Suhua Fu 1, 3 , Bofu Yu 4 , Guanghui Zhang 1
Affiliation  

The sediment transport capacity plays a pivotal role in erosion research, and is usually predicted using hydraulic variables. The transport capacity and hydraulic variables are affected by vegetation cover. Our understanding of the effect of vegetation cover, including the size, density, and arrangement of vegetation stems, on the relationship between the sediment transport capacity and hydraulic variables were rather limited. The objectives of this study were to investigate the effect vegetation stem cover on the relationship between hydraulic variables and the sediment transport capacity and to derive an equation for predicting the sediment transport capacity in the presence of vegetation cover. Five data sets from 288 flume experiments with a wide range of discharge (0.25–2 × 10−3 m3 s−1), slope (8.8–42.3%), median sediment diameter (0.11–1.16 × 10−3 m), stem cover (0–30%), stem diameter (2–36 mm), and stem arrangement (bead, tessellation, zigzag, random, and banding) were compiled for this study. Extensive regression analysis has shown that the sediment transport capacity could be expressed as a power function of flow velocity, shear stress, stream power, or unit stream power. Predictors of the sediment transport capacity were ranked from the unit stream power as the strongest, followed by the stream power, flow velocity, and the shear stress. Vegetation stem cover had no apparent and direct effect on the relationship between hydraulic variables and the sediment transport capacity so long as the unit stream power or stream power was used as its predictor. Vegetation cover became a significant factor only when the shear stress was used to predict the sediment transport capacity. Finally, a new equation involving the slope gradient, flow velocity, and median sediment diameter in a nondimensional form was shown to be a superior predictor of the sediment transport capacity with the Nash–Sutcliffe coefficient of efficiency of 0.92. The product of slope and flow velocity, that is, the unit stream power, captures the effect of vegetation stem cover and surface roughness and was shown to be an effective predictor of the transport capacity in the presence of vegetation cover.

中文翻译:

在有植被覆盖的情况下,从流动条件和颗粒大小预测泥沙输送能力

泥沙输送能力在侵蚀研究中起着关键作用,通常使用水力变量进行预测。运输能力和水力变量受植被覆盖的影响。我们对植被覆盖的影响,包括植被茎的大小、密度和排列,对输沙能力和水力变量之间关系的理解相当有限。本研究的目的是研究植被茎干覆盖对水力变量和泥沙输送能力之间关系的影响,并推导出一个方程来预测存在植被覆盖时的泥沙输送能力。来自 288 个水槽实验的五个数据集,具有广泛的排放量 (0.25–2 × 10−3 m3 s−1)、坡度 (8.8–42.3%)、中值沉积物直径 (0.11–1. 16 × 10−3 m)、茎盖 (0–30%)、茎直径 (2–36 mm) 和茎排列(珠、镶嵌、锯齿形、随机和带状)为本研究编制。广泛的回归分析表明,泥沙输运能力可以表示为流速、剪切应力、河流功率或单位河流功率的幂函数。泥沙运移能力的预测因子从单位河流功率排序为最强,其次是河流功率、流速和剪切应力。只要以单位河流功率或河流功率作为预测因子,植被茎干盖度对水力变量与输沙能力之间的关系没有明显的直接影响。只有当剪应力被用来预测泥沙输运能力时,植被覆盖才成为一个重要因素。最后,一个包含无量纲形式的坡度、流速和中值沉积物直径的新方程被证明是沉积物输送能力的优越预测器,其 Nash-Sutcliffe 效率系数为 0.92。坡度和流速的乘积,即单位流功率,捕捉了植被茎干覆盖和表面粗糙度的影响,并被证明是存在植被覆盖时运输能力的有效预测因子。
更新日期:2020-10-18
down
wechat
bug