RAPID: Characterizing Sediment Mobilization and Landscape Response to the Combined Effects of Wildfire and Extreme Flooding along Fourmile Canyon, Front Range Colorado

该RAPID项目的重点是2013年9月异常降雨事件后洪水和侵蚀对科罗拉多前山脉Fourmile峡谷的影响。 该集水区仍在应对2010年25平方公里的野火，该团队将测试2013年洪水重新改造和沉积沉积物最初由早期火灾动员的假设。 该小组将研究2013年洪水沉积物，侵蚀山坡，侧支流和沟壑沉积物，以及沿着峡谷梯田下新暴露的沉积物。他们将重新访问正在进行的火灾后研究的一部分，并将使用这些沉积物中的短寿命沉降物放射性核素（7 Be，137 Cs和210 Pb）来帮助识别再活化的火灾沉积物。此外，他们还将分析山谷沉积物的地球化学和地层学，并将短期野火和与植被相关的侵蚀措施与正在进行的记录过去10，000 - 30，000年侵蚀速率和山坡过程的研究进行比较。必须尽快对2013年9月洪水期间形成的沉积物和暴露物进行采样和研究，以免它们随着道路重建、河道整治和景观恢复的进行而退化和消失。 这些新的曝光大大提高了使用14 C分析和测定全新世斜坡和山谷地层的能力。这项工作将提高人们对野火和大规模洪水发生率增加对景观和生活在那里的人造成的后果的认识。 因此，项目成果将为减灾和抗灾提供信息。 该团队将利用与USGS科学家和博尔德溪临界区天文台的现有合作，并将直接涉及本科生和研究生。

This RAPID project focuses on the impacts of flooding and erosion on Fourmile Canyon in the Colorado Front Range following the exceptional September 2013 rainfall event. The catchment is still responding to a 25 km2 wildfire in 2010 and the team will test the hypothesis that the 2013 flood reworked and deposited sediments initially mobilized by the earlier fires. The team will study the 2013 flood deposits, eroded hillslopes, side-tributary and gully deposits, and deposits freshly exposed beneath terraces along the canyon. They will revisit locations that have been part of an ongoing post-fire study, and will use short-lived fallout radionuclides (7Be, 137Cs, and 210Pb) in these deposits to help identify remobilized fire sediments. In addition, they will analyze the geochemistry and stratigraphy of valley deposits and compare measures of short-term wildfire and flooding-related erosion with ongoing studies documenting erosion rates and hillslope processes over the past 10,000-30,000 years. Sediment deposits and exposures that formed during the September 2013 flooding must be sampled and studied soon, before they degrade and disappear as road rebuilding, channel manipulation, and landscape recovery proceeds. These new exposures greatly increase the ability to analyze and date Holocene slope and valley stratigraphy using 14C. The work will enhance understanding of consequences of increased incidence of wildfires and large-magnitude floods on the landscape and those who live there. As such, the project outcomes will inform hazard mitigation and resilience. The team will leverage existing collaborations with USGS scientists and the Boulder Creek Critical Zone Observatory, and will directly involve undergraduates and a graduate student.