RAPID: Post-fire lidar change detection, Eagle Creek fire, Columbia River Gorge, Oregon

美国西部野火活动的增加大大增加了快速，高度破坏性泥石流的可能性，并导致了快速的土壤侵蚀和岩崩。泥石流起源于陡峭的集水区，在进入邻近的低地之前，它们携带着沉积物和碎片，因此，它们对人类生命和基础设施构成了日益严重的威胁。2017年9月，鹰溪大火烧毁了俄勒冈州哥伦比亚河峡谷南缘近5万英亩陡峭的森林地形。缺乏确定鹰溪火区火灾后地貌反应相关性所需的数据和实地观测。该项目应对了火灾后收集数据和实地观测的严重紧迫性，并可能影响管理活动。该项目将为泥石流潜力的基于过程的地貌模型提供信息，并为极端事件对区域侵蚀和产沙量的贡献提供重要的约束条件。工作计划包括基于光栅和点云的变化检测与激光雷达数据集。激光雷达分析记录了2014年至2018年间森林和亚冠层结构的变化，这将使研究小组能够量化植被马赛克不同组成部分的干扰如何影响沉积物的输送。对火灾后地表变化的分析将使研究小组能够测试颗粒大小和斜坡角度如何调节由于扰动而产生的运输距离。2018年夏季的实地工作将在减灾活动覆盖火灾后地貌变化之前进行。该小组将确定可能产生泥石流的厚沉积物堆积的山坡地点，并确定对基础设施的损害。多个州和联邦机构都参与其中，研究生将接受激光雷达技术专家的培训。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Increased wildfire activity in the Western U.S. significantly increases the likelihood of rapid, highly destructive debris flows as well as contributes to rapid soil erosion and rockfall. Debris flows emanate from steep catchments where they entrain sediment and debris before entering adjacent lowlands, and thus, they pose an increasingly significant threat to human life and infrastructure. In September 2017, the Eagle Creek fire complex burned nearly 50,000 acres of steep, forested terrain along the southern margin of the Columbia River Gorge in Oregon. Data and field observations necessary to determine the relevance of post-fire geomorphic responses in the Eagle Creek fire region are lacking. This project responds to the severe urgency to collect data and field observations following the fire, and could impact management activities. This project will inform process-based geomorphic models of debris flow potential and provide important constraints on the contribution of extreme events to regional erosion and sediment yield. The work plan includes raster and point-cloud based change-detection with lidar datasets. Lidar analysis documenting changes in the forest and sub-canopy structure between 2014 and 2018 will enable the team to quantify how the disturbance of different components of the vegetation mosaic contribute to sediment transport. Analysis of post-fire land surface change will enable the team to test how grain size and slope angle regulate transport distances owing to disturbance. Fieldwork in summer 2018 will occur before mitigation activities overprint post-fire geomorphic change. The team will identify hillslope sites with thick sediment accumulation that are likely to produce debris flows and identify damage to infrastructure. Various state and federal agencies are involved and a graduate student will receive training from experts in lidar techniques.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.