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The dynamics of gully-head erosion on a semi-arid piedmont plain, Baringo District, Kenya.

机译：肯尼亚巴林哥区半干旱山前平原上的沟壑侵蚀动力学。

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Gully-head erosion processes were monitored in a degraded semi-arid piedmont plain in Baringo District, Kenya, in order to understand the temporal and spatial variation in migration. The study was conducted at three sites, i.e., Lameluk (main site), Marigat Airstrip and Eldume.; A sediment budget for a gully head and contributing drainage area in the Lameluk area reveals that the gully head is a major source of sediment: approximately fifty percent of the total amount of sediment originates from the headcut. Two major processes, i.e., waterfall erosion and side-wall collapse, are active in headcut development. Although waterfall erosion is highly correlated with the number of dry days preceding a storm, it contributes to only 13% of the total headcut erosion. Side-wall erosion is better correlated with runoff.; The results of both rainfall simulation and overland flow experiments show that, despite the high infiltration capacities, runoff is quickly generated due to the low surface roughness of hillslopes (K {dollar}>{dollar} 300). Furthermore, it was demonstrated that micro-steps can converge runoff and create erosive flow conditions. Rill or gully initiation is probably associated with high-magnitude storms.; The curvature of gully heads appears to be associated with the contour patterns of the surrounding catchments. Each headcut curvature is characterized by different growth rates and can be used as an indicator of gully head erosion.; At Marigat, subsurface-flow gullies are characterized by a highly erratic growth pattern as a consequence of frequent changes within the tunnel network. At Eldume, ephemeral rill systems can concentrate runoff to deeply incised channels and cause headcut development in the highly erodible soils.; The results demonstrate the importance of the gully head as the link between the hillslope and the channel systems and show that the morphology of the gully head indicates both the type and the intensity of the erosion processes. This knowledge can improve geomorphological models as well as soil conservation methods.
机译：为了了解迁徙的时空变化，在肯尼亚巴林哥区一个退化的半干旱山前平原中监测了沟壑侵蚀过程。该研究在三个地点进行，即Lameluk（主要地点），Marigat Airstrip和Eldume。拉梅鲁克地区一个沟壑头和主要排水区的沉积物预算表明，沟壑头是沉积物的主要来源：大约50％的沉积物总量来自the头。头部发展中活跃着两个主要过程，即瀑布侵蚀和侧壁塌陷。尽管瀑布侵蚀与暴风雨来临前的干旱天数高度相关，但它仅占全部顶蚀侵蚀的13％。侧壁侵蚀与径流更好地相关。降雨模拟和陆上水流实验的结果表明，尽管入渗能力高，但由于山坡的表面粗糙度低（K {dollar}> {dollar} 300），因此会迅速产生径流。此外，已证明微步可以汇聚径流并产生侵蚀性流动条件。沟壑或沟壑的启动可能与高强度风暴有关。沟壑的弯曲似乎与周围流域的轮廓模式有关。每个头切曲率的特征在于不同的增长率，可以用作沟壑侵蚀的指标。在Marigat，地下水沟的特征是隧道网络内频繁变化导致高度不稳定的增长模式。在Eldume，短暂的钻探系统可以将径流集中到深切的渠道上，并在高度易蚀的土壤中引起割据的发展。结果证明了沟渠头作为山坡和河道系统之间联系的重要性，并表明沟渠头的形态既表明了侵蚀过程的类型，也表明了侵蚀过程的强度。这些知识可以改善地貌模型以及土壤保护方法。

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