Characteristics of sediment deposits formed by intense rainfall events in small catchments in the Belgian Loam Belt
Characteristics of sediment deposits formed by intense rainfall events in small catchments in the Belgian Loam Belt
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DOI：
10.1016/s0169-555x(99)00068-9
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发表时间：
2000-02-01
期刊：
影响因子：
3.9
通讯作者：
Poesen, J
中科院分区：
文献类型：
--
作者：
Beuselinck, L;Steegen, A;Poesen, J
在比利时壤土带的两个农业集水区内，绘制了一次强降雨事件后的侵蚀和沉积模式图，并测量了其体积。根据这些数据，计算出了总的侵蚀和沉积收支。调查清楚地表明，可以根据导致沉积的过程类型来区分沉积物。对于大多数沉积物来说，地形是控制因素。然而，在植被屏障导致沉积的农田边界也发现了大量沉积物。植被控制的沉积发生在比坡度控制的沉积物沉积明显更高的坡度上。这意味着植被控制的沉积对沉积泥沙的空间分布以及集水区出口的泥沙输移比具有重要影响。植被屏障前泥沙沉积物的未分散团聚体粒径分布比地形控制条件下沉积的泥沙更细。然而，两种类型泥沙的分散粒径分布非常相似，且仅比源物质的分散粒径分布略粗。在这些极端降雨事件中，泥沙以团聚体形式被侵蚀、搬运和沉积。团聚体本身具有与源物质非常相似的粒径分布。因此，预计会被输送到河流系统的大量细颗粒物质及相关污染物被困在集水区内。（C）2000爱思唯尔科学出版社。版权所有。
Erosion and deposition patterns within two agricultural catchments in the Belgian Loam Belt were mapped and their volumes measured after an intense rainfall event. From these data, the total erosion and deposition budget was calculated. The surveys clearly indicated that deposits could be differentiated according to the type of process that caused deposition. For most deposits topography was the controlling factor. However, important deposits were also found at field borders where a vegetation barrier caused deposition. Vegetation-controlled deposition occurs at significantly higher slope gradients than slope-controlled sediment deposition. This implies that vegetation-controlled deposition has an important effect on the spatial distribution of deposited sediment and on the sediment delivery ratio at the catchment outlet. The undispersed aggregate-size distribution of sediment deposits in front of vegetation barriers is finer than the sediment deposited under topographically-controlled conditions. However, the dispersed particle-size distributions of both types of sediment are very similar and only slightly coarser than the dispersed particle-size distribution of the source material. During these extreme rainfall events, sediment is eroded, transported and deposited in aggregated form. The aggregates themselves have a particle size distribution, closely resembling the source material. Consequently, considerable quantities of fine material and associated pollutants, which are expected to be exported to the river system, are trapped within the catchment. (C) 2000 Elsevier Science B.V. All rights reserved.