Controls on gully formation following forest clearing in a humid temperate environment
Controls on gully formation following forest clearing in a humid temperate environment
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DOI：
10.1029/98wr02513
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发表时间：
1998-12
影响因子：
5.4
通讯作者：
I. Prosser;M. Soufi
中科院分区：
文献类型：
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作者：
I. Prosser;M. Soufi
我们已经建立了过去15年来澳大利亚东南部庞巴拉附近被侵蚀成松树种植园的沟壑的沟壑起始、森林清理和降雨事件的年表。年表表明，日降雨量为80-100毫米，每隔1.4-2年重复一次，可能会在前一年内清除原生森林的地区引发沟壑侵蚀。日降雨量为200毫米，经历了大规模的沟壑侵蚀，反复出现时间为10-15年。对航道启动的抵抗在干扰的一年内有效地恢复，只允许有限的机会侵蚀。利用数字高程模型对沟壑侵蚀的空间格局进行了分析，结果表明，沟壑是从所有景观位置开始形成的。与以前的研究不同，没有明确的地形阈值来限制沟渠网络的范围。我们推断，较弱的地形门槛是由于低的冲刷阻力造成的，使得局部水流汇聚主导了地形水流的积累。尽管与以前的研究相比，冲刷阻力较低，但沟谷起始的过程阈值仍然是侵蚀过程的一种有用的简化。对于我们研究的土壤，沟壑侵蚀的门槛与暴露可侵蚀底土的强烈冲刷有关。
We have constructed a chronology of gully initiation, forest clearing, and rainfall events for gullies eroded into pine plantations near Bombala, southeastern Australia, over the last 15 years. The chronology suggests that daily rainfall of 80–100 mm, which has a recurrence interval of 1.4–2 years, can initiate gully erosion on areas cleared of native forest within the previous year. Massive gully erosion was experienced from a daily rainfall of 200 mm with a recurrence of 10–15 years. Resistance to channel initiation effectively recovers within a year of disturbance, allowing only a limited opportunity for erosion. Analysis of the spatial pattern of gully erosion, using a digital elevation model, shows that gullies were initiated across all landscape positions. In contrast to previous studies, there is no clear topographic threshold that limits the extent of the gully network. We infer that the weak topographic threshold results from low resistance to scour, allowing local flow convergence to dominate over topographic accumulation of flow. Although resistance to scour is low relative to previous studies, a process threshold for gully initiation is still a useful simplification of the erosion processes. For the soils that we studied, the threshold for gully erosion relates to intense scour exposing erodible subsoils.