The relationship between drainage density, erosion rate, and hilltop curvature: Implications for sediment transport processes
The relationship between drainage density, erosion rate, and hilltop curvature: Implications for sediment transport processes
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排水密度、侵蚀率和山顶曲率之间的关系：对沉积物输送过程的影响
DOI：
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发表时间：
2015
期刊：
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通讯作者：
S. Grieve
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作者：
F. Clubb;S. Mudd;Mikael Attal;D. Milodowski;S. Grieve
流域密度是描述河流网络范围的基本景观指标。我们使用渠道-山坡综合景观开发（CHILD）数值模型比较了排水密度（Dd）和侵蚀速率（E）之间的关系。我们发现，在脱离限制河流下切模型中改变河道坡度指数（n）可以控制Dd和E之间的关系，如果所有其他参数保持不变，则n > 1会导致Dd随E增加。这一结果是一致的线性和非线性坡面泥沙通量模型。我们还测试了美国五个土壤覆盖景观中Dd和E之间的关系：羽毛河，加利福尼亚州;圣加布里埃尔山，加利福尼亚州;博尔德溪，CO;瓜达卢佩山，NM;和比特鲁特国家森林，ID。对于其中两个现场，我们将Dd与宇宙成因放射性核素（CRN）衍生的侵蚀率进行比较，对于每个站点，我们使用平均山顶曲率作为侵蚀速率的代理，其中CRN推导的侵蚀速率不可用。我们发现，有一个显着的正相关关系之间的DD，E，和山顶曲率在每个网站，除了圣盖博山脉，加利福尼亚州。这种关系与n指数大于1一致，表明在较高的侵蚀速率下，平流和扩散过程之间的过渡发生在土壤覆盖景观中较小的贡献区域。
Drainage density is a fundamental landscape metric describing the extent of the fluvial network. We compare the relationship between drainage density (Dd) and erosion rate (E) using the Channel‐Hillslope Integrated Landscape Development (CHILD) numerical model. We find that varying the channel slope exponent (n) in detachment‐limited fluvial incision models controls the relationship between Dd and E, with n > 1 resulting in increasing Dd with E if all other parameters are held constant. This result is consistent when modeling both linear and nonlinear hillslope sediment flux. We also test the relationship between Dd and E in five soil‐mantled landscapes throughout the USA: Feather River, CA; San Gabriel Mountains, CA; Boulder Creek, CO; Guadalupe Mountains, NM; and Bitterroot National Forest, ID. For two of these field sites we compare Dd to cosmogenic radionuclide (CRN)‐derived erosion rates, and for each site we use mean hilltop curvature as a proxy for erosion rate where CRN‐derived erosion rates are not available. We find that there is a significant positive relationship between Dd, E, and hilltop curvature across every site, with the exception of the San Gabriel Mountains, CA. This relationship is consistent with an n exponent greater than 1, suggesting that at higher erosion rates, the transition between advective and diffusive processes occurs at smaller contributing areas in soil‐mantled landscapes.