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Post-fire stream channel processes: Changes in runoff rates, sediment delivery across spatial scales, and mitigation effectiveness.

机译：火后河道过程：径流量变化，跨空间尺度的泥沙输送和缓解效果的变化。

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摘要

Wildfires dramatically affect hydrologic processes including runoff and erosion, which in turn can impact society. Disturbance by fire creates ecosystem heterogeneity, prompting many species to adapt to fire cycles. Human impacts have altered fire frequency and affected natural systems to the point that additional landscape-scale disturbances may cause a disruption in ecosystem form and function. The altered ecosystems and increased development in forests may exacerbate post-fire impacts, affecting more of the population in fire-prone regions.;The following three studies will improve our understanding and management of post-fire impacts on stream channel processes. A catchment in eastern Arizona where runoff data were collected between 1962 and 1983 was subsequently burned by a wildfire in 2011. The direct comparison of pre and post-fire runoff showed that the fire made runoff more rapid, increased peak discharge rates, and compressed the time scale of storm hydrographs. These results can help improve post-fire runoff modeling and management efforts.;The second topic addressed the scaling of sediment delivery across hillslope and small catchment scales. Erosion data used in this study were from the Arizona site and five other sites across the western US. Results from five of the six sites showed that sediment delivery significantly decreased with increasing spatial extent, while the lack of trend at the sixth site illustrates the variability in erosion responses across ecosystems. The relationships developed in this study will help improve estimates of sediment delivery rates at the small-catchment scale using more easily acquired data from small plots.;The third study addressed whether straw bale check dams reduce post-fire sediment yields or affect ephemeral stream channel morphology. A series of laboratory flume experiments based on measured post-fire field conditions showed that check dams can store sediment from initial runoff events, but that a large number of check dams would be needed to reduce post-fire sediment yields. The stored sediment reduced the local channel gradient, but the check dams did not otherwise affect the channel morphology. These data and field observations were used to develop a check dam classification system that can be applied in ephemeral streams in burned or unburned areas.
机译：野火会极大地影响水文过程，包括径流和侵蚀，进而会影响社会。火灾干扰造成生态系统异质性，促使许多物种适应火灾循环。人类的影响已经改变了火灾频率并影响了自然系统，以至于其他景观尺度的干扰可能导致生态系统形式和功能的破坏。生态系统的变化和森林的发展可能加剧火灾后的影响，并在易火地区影响更多的人口。以下三项研究将增进我们对火灾后对河道过程的影响的理解和管理。亚利桑那州东部的一个流域在1962年至1983年期间收集了径流数据，随后在2011年被一场野火烧毁。直接比较火前和火后的径流，结果表明火势使径流更加迅速，增加了峰值排放速率，并压缩了径流。暴雨水位图的时间尺度。这些结果可以帮助改善火灾后径流的建模和管理工作。第二个主题是跨山坡和小流域尺度的泥沙输送规模。本研究中使用的侵蚀数据来自亚利桑那州的站点和美国西部其他五个站点。六个地点中五个地点的结果表明，沉积物的输送随着空间范围的增加而显着下降，而第六个地点缺乏趋势说明了整个生态系统中侵蚀响应的变化。这项研究中建立的关系将有助于利用小块土地上更容易获得的数据来提高小流域尺度上的泥沙输送速率的估算。第三项研究探讨了草捆止水坝是否减少了大火后的泥沙产量或影响了短暂的河道。形态学。根据测得的火后野外条件进行的一系列实验室水槽实验表明，止水坝可以储存初始径流事件中的沉积物，但是需要大量的止水坝以减少火灾后的沉积物产量。所储存的沉积物降低了局部河道的坡度，但止水坝并未以其他方式影响河道的形态。这些数据和现场观察被用于开发一个检查坝分类系统，该系统可用于燃烧或未燃烧区域的临时河流。

著录项

  • 作者

    Wagenbrenner, Joseph William.;

  • 作者单位

    Washington State University.;

  • 授予单位 Washington State University.;
  • 学科 Hydrologic sciences.;Geomorphology.;Civil engineering.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 157 p.
  • 总页数 157
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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