Erosive dynamics of channels incised by subsurface water flow
Erosive dynamics of channels incised by subsurface water flow
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地下水流切割河道的侵蚀动力学
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
D. Rothman
中科院分区：
文献类型：
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作者：
A. Lobkovsky;B. Smith;A. Kudrolli;D. Mohrig;D. Rothman
我们提出了一个被地下水切割成可蚀河床的河道的动力学模型。该模型在实验室尺度实验中通过河道生长的时间分辨地形测量进行了验证。实验中的表面高度是通过一种新的激光辅助成像技术来测量的。模型中的侵蚀速率由扩散和平流分量组成，并由一个简单的渗流驱动项组成。稳定的行驶条件可能存在，只要通道被一个由稳定（平均）降雨补充的地下水位切割成平坦和水平的可侵蚀河床。在这种稳定的驱动条件下，该模型预测了沟道断面的渐近自相似生长形状。相反，给定在稳定行驶条件下形成的样带形状，以及对通道底部侵蚀速率的估计，则可以从静态通道形状推断出颗粒输运系数。我们报告了在佛罗里达州阿巴拉契科拉河流域切割成松散沙子的沟壑系统的这些运输系数的估计。
[1] We propose a dynamical model for channels incised into an erodible bed by subsurface water flow. The model is validated by the time-resolved topographic measurements of channel growth in a laboratory-scale experiment. Surface heights in the experiment are measured via a novel laser-aided imaging technique. The erosion rate in the model is composed of diffusive and advective components as well as a simple driving term due to the seeping water. Steady driving conditions may exist whenever channels are incised into a flat and level erodible bed by a water table replenished via steady (on average) rainfall. Under such steady driving conditions, the model predicts an asymptotically self-similar growing shape for the channel transects. Conversely, given a transect shape that evolved under steady driving conditions and an estimate of the erosion rate at the bottom of the channel, granular transport coefficients can be inferred from the static channel shape. We report an estimate of these transport coefficients for a system of ravines incised into unconsolidated sand in the Apalachicola River basin, Florida.