Abstract Dimensionless morphological ratios (DMR) generally are used in systemic proposals for stream classification and river restoration projects. Often, such morphometric parameters, including field data from channel cross sections, develop into a template for a given geomorphic reference site. In this study, high-resolution Digital Terrain Models (HRDTMs), combined with orthophotographs from 2018 and ground-based surveys, were used to analyze the spatial variability of DMR in a semi-arid ephemeral stream subject to changes in stream power under bankfull conditions. In particular, a channel reach of 2.7 km in length along the Upper Mula stream in southeastern Spain was chosen to test the relationships between the two types of variables. Rosgen's DMR (width to depth ratio, entrenchment ratio, bank height ratio) and hydraulic data at bankfull stage (flow velocity, Froude number, shear stress, mean stream power and energy gradient, among others) were calculated by 1D hydrodynamic modeling and HRDTMs prior entry of field information. The resulting maps allowed comparison of stream power with DMR in relation to the channel stretch class and bed stability. The results showed similar spatial patterns for the width to depth ratio and the bank height ratio. The average values estimated in bend stretches were lower than along straight and slightly sinuous stretches and very similar to those of sub-reaches from the inflection point to the meander bend apex. However, the entrenchment ratio followed a different pattern, according to which the straight and slightly sinuous stretches were the most entrenched and the bend stretches presented a more moderate average entrenchment ratio. In addition, the energy balance and power gradient also experienced spatial variations in relation to the bed stability and DMR. Only in highly incised sub-reaches were such relationships not significant. The lack of a significant correlation between excess energy and bank height ratio or width to depth ratio over short lag distances was also verified, regardless of the affected bedforms. An ANOVA showed important differences between the straight and slightly sinuous stretches and bend stretches, which were strongly influenced by the incision and entrenchment ratios and the maximum bankfull depth.

中文翻译：

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无量纲形态比率与短暂通道中bankfull阶段的流功率变化

摘要 无量纲形态比 (DMR) 通常用于河流分类和河流修复项目的系统建议。通常，这种形态测量参数，包括来自通道横截面的现场数据，会发展成为给定地貌参考站点的模板。在这项研究中，高分辨率数字地形模型 (HRDTM) 结合 2018 年的正射影像和地面调查，用于分析半干旱短暂河流中 DMR 的空间变异性，该河流在满岸条件下会发生变化. 特别是，选择了西班牙东南部沿穆拉河上游 2.7 公里长的河道范围来测试两类变量之间的关系。Rosgen 的 DMR（宽深比、壕沟比、岸高比）和全岸阶段的水力数据（流速、弗劳德数、剪切应力、平均河流功率和能量梯度等）是通过一维水动力模型和 HRDTM 在输入现场信息之前计算出来的。由此产生的地图允许将流功率与 DMR 与通道拉伸等级和床稳定性进行比较。结果表明，宽深比和堤高比的空间模式相似。在弯曲段估计的平均值低于沿直线和略微弯曲的段，并且非常类似于从拐点到曲折弯曲顶点的子段。然而，防御率遵循了不同的模式，据此，直线和略微弯曲的路段是最根深蒂固的，而弯曲路段呈现出更适中的平均水深比。此外，能量平衡和功率梯度也经历了与床稳定性和 DMR 相关的空间变化。只有在高度切割的子范围内，这种关系才不显着。无论受影响的床型如何，还验证了在短滞后距离内，过剩能量与堤岸高度比或宽度与深度比之间缺乏显着相关性。ANOVA 显示直线和略微弯曲的伸展和弯曲伸展之间的重要差异，这受到切口和挖沟比率以及最大坡度深度的强烈影响。能量平衡和功率梯度也经历了与床稳定性和 DMR 相关的空间变化。只有在高度切割的子范围内，这种关系才不显着。无论受影响的床型如何，还验证了在短滞后距离内，过剩能量与堤岸高度比或宽度与深度比之间缺乏显着相关性。ANOVA 显示直线和略微弯曲的伸展和弯曲伸展之间的重要差异，这受到切口和挖沟比率以及最大坡度深度的强烈影响。能量平衡和功率梯度也经历了与床稳定性和 DMR 相关的空间变化。只有在高度切割的子范围内，这种关系才不显着。还验证了在短滞后距离内，过剩能量与堤岸高度比或宽度与深度比之间缺乏显着相关性，而不管受影响的河床形态如何。ANOVA 显示直线和略微弯曲的伸展和弯曲伸展之间的重要差异，这受到切口和挖沟比率以及最大坡度深度的强烈影响。无论受影响的床型如何，还验证了在短滞后距离内，过剩能量与堤岸高度比或宽度与深度比之间缺乏显着相关性。ANOVA 显示直线和略微弯曲的伸展和弯曲伸展之间的重要差异，这受到切口和挖沟比率以及最大坡度深度的强烈影响。无论受影响的床型如何，还验证了在短滞后距离内，过剩能量与堤岸高度比或宽度与深度比之间缺乏显着相关性。ANOVA 显示直线和略微弯曲的伸展和弯曲伸展之间的重要差异，这受到切口和挖沟比率以及最大坡度深度的强烈影响。