Discriminating fine sediment sources and the application of sediment tracers in burned catchments: a review
Discriminating fine sediment sources and the application of sediment tracers in burned catchments: a review
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DOI：
10.1002/hyp.9537
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发表时间：
2013-03
影响因子：
3.2
通讯作者：
H. Smith;W. Blake;P. Owens
中科院分区：
文献类型：
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作者：
H. Smith;W. Blake;P. Owens
野火可能会导致径流、侵蚀和下游沉积物输送过程发生重大变化。为了应对这些干扰效应，燃烧流域内沉积物的主要输送来源也可能发生变化。沉积物追踪提供了一种方法来确定燃烧流域源中细沉积物（通常<63 µm）的比例贡献。在本文中，我们回顾了各种沉积物示踪剂在区分野火后细小的沉积物来源方面的应用。沉降放射性核素为区分山坡表面和地下（通常是河道岸）来源提供了最有效的示踪剂。以前对野火后这些来源的贡献进行量化的示踪剂研究完全基于放射性核素。沉降放射性核素区分根据燃烧和未燃烧区域定义的空间源的潜力取决于与燃烧相关的表层土壤浓度变化。由于表面材料中的大多数放射性核素与灰烬而不是土壤结合，因此追踪燃烧和未燃烧的源区域将是有问题的。表层土壤的地球化学特性可能太容易受到自然和烧伤相关变异的影响，无法一致地区分烧伤定义的空间源。矿物磁性已显示出区分不同严重程度的烧毁土壤以及未烧毁区域的潜力。需要更多的研究来评估土壤有机化合物作为烧毁源区域示踪剂的用途。将基于放射性核素的山坡和河道源判别与过程测量和火灾后监测联系起来，可以增强对细泥沙转移和相关水质影响的了解。采用这种综合和多尺度的方法将有助于加深对野火水文和地貌响应的了解。版权所有 © 2012 约翰·威利父子有限公司
Wildfire can cause substantial changes to runoff, erosion and downstream sediment delivery processes. In response to these disturbance effects, the main sources of sediment transported within burned catchments may also change. Sediment tracing offers an approach to determine the proportional contributions of fine sediment (typically <63 µm) from burned catchment sources. In this paper, we review the application of various sediment tracers to discriminate fine sediment sources following wildfire. Fallout radionuclides provide the most effective tracers for discriminating hillslope surface and sub‐surface (usually channel bank) sources. Previous tracer studies quantifying contributions from these sources after wildfire are based exclusively on radionuclides. The potential for fallout radionuclides to discriminate spatial sources defined according to burned and unburned areas depends on burn‐related changes in surface soil concentrations. Tracing of burned and unburned source areas will be problematic where most radionuclides in surface material are bound to ash rather than soil. Geochemical properties of surface soils are probably too susceptible to natural and burn‐related variability to consistently discriminate burn‐defined spatial sources. Mineral magnetic properties have shown potential for discriminating soil burned at different severities as well as unburned areas. More research is needed to assess the use of soil organic compounds as tracers of burned source areas. Linking fallout radionuclide‐based hillslope and channel source discrimination with process measurements and monitoring after fire can provide enhanced insight into fine sediment transfer and related water quality impacts. Adopting such integrated and multi‐scale approaches would contribute to improved understanding of hydrological and geomorphological responses to wildfire. Copyright © 2012 John Wiley & Sons, Ltd.