Response of a soil‐mantled experimental landscape to exogenic forcing
Response of a soil‐mantled experimental landscape to exogenic forcing
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DOI：
10.1029/2012wr012283
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发表时间：
2012-10
影响因子：
5.4
通讯作者：
L. M. Gordon;S. Bennett;R. Wells
中科院分区：
文献类型：
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作者：
L. M. Gordon;S. Bennett;R. Wells
土壤侵蚀会严重破坏景观，细沟和沟壑等集中径流可能是土壤流失的主要因素。本文利用模拟降雨和下游基准面下降的土壤覆盖的实验景观，研究了细沟和细沟网络的生长、发育和时空演变。细沟切割和网络发育伸展是由于基准面下降在水槽出口形成的水头的积极迁移造成的。由于这种外生的强迫，这种退化波的传播在太空中发生得非常快，并导致整个网络中几乎相同数量的床面切割。细沟切割、河道发育和泥沙排出的峰值时有发生，但这些都是对下游基准面调整的直接反应。尽管水流的供应有限，但大多数沉积物的外流在基因上与陡峭的发育和迁移有关。侵蚀细沟的几何形状和坡头迁移速率与陆面流量有很好的相关性。这些发现对预测土壤流失、细沟网络发育以及可能发生水头侵蚀的景观演变具有重要意义。
Soil erosion can severely degrade landscapes, and concentrated flows such as rills and gullies can be the dominant contributor to the soil losses. This paper examines the growth, development, and spatiotemporal evolution of rills and rill networks using a soil‐mantled experimental landscape subjected to simulated rain and downstream base level lowering. Rill incision and network development and extension occurred due to actively migrating headcuts formed at the flume outlet by base level lowering. The communication of this wave of degradation due to this exogenic forcing occurred very quickly in space, and resulted in nearly the same amount of bed incision throughout the network. Rill incision, channel development, and peaks in sediment efflux occurred episodically, yet these were in direct response to the downstream base level adjustments. Although flows were supply limited, most of the sediment efflux was genetically linked to headcut development and migration. The geometry of the eroded rills and the rates of headcut migration were well correlated to overland flow rate. These findings have important implications for the prediction of soil loss, rill network development, and landscape evolution where headcut erosion can occur.