RAPID: Collaborative Research: Sediment and Contaminant Mobilization by Extreme Flooding Associated with Hurricane Florence

高强度的河流洪水是一个日益被认识到的过程，塑造景观，动员沉积物和污染物，建立地层记录。热带气旋是造成极端降水和造成高强度河流洪水的主要机制。飓风佛罗伦萨于2018年9月14日在北卡罗来纳州登陆，并在大西洋沿岸平原下游的河流上产生强降水和历史性洪水。这些洪水重塑了洪泛平原，并从该地区的工业中调动了一系列污染物，为研究极端洪水的地貌和环境影响提供了独特的机会。PI将系统地收集Pee Dee河系统下游洪水沉积的沉积物，Pee Dee河系统是美国东南部最大的流域之一，以调查飓风登陆造成洪水后沉积物和相关污染物沉积的横向和纵向模式。这项研究将阐明极端洪水事件如何将沉积物和污染物从陆地携带到海洋，这是一个影响沿途沿着人类和生态系统健康的过程。确定和量化对Winyah湾的污染物输入对沿海生态系统管理和公众健康具有重要意义。调查结果将传达给当地利益攸关方和决策者。该项目将资助一个多学科团队，其中包括地球科学家，环境科学家和环境工程师在一系列的职业阶段。来自沿海卡罗莱纳大学和东北大学的一组不同的本科生和研究生将参加拟议的活动，以获得研究经验，并开发可以纳入其学术课程的研究活动。登陆飓风在大西洋沿岸平原产生河流洪水危害，影响数百万地区的居民。该项目利用罕见的极端洪水来观察这种类型的事件如何塑造冲积河流系统的洪泛区，并将沉积物和污染物从陆地和点源输送到沿海海洋。PI将在其他过程去除或侵蚀洪水沉积物之前收集洪水沉积物样本。他们将分析沉积物特征，进行沉积物的7 Be测年以确认沉积时间，并测量洪水沉积物中有机物（多环芳烃; PAH）和微量金属（V，Cr，Mn，Fe，Co，Ni，Cu，Zn，As，Se，Ag，Cd，Sn，Hg，Pb和Bi）污染物的浓度。就像飓风哈维（2017）造成的洪水和污染物研究一样，这项工作具有高度相关性，并说明了将污染物扩散作为公共卫生问题进行跟踪的必要性。使用多环芳烃和所选的痕量金属将为多环芳烃化合物提供更强的来源识别，例如，来自道路、停车场密封层或与煤燃烧有关的径流。拟议的活动以一个正在进行的国家科学基金会项目（编号1804799）为基础，该项目支持专业研究员Munoz和Shen，通过提供极端洪水沉积物沉积的现代模拟，开发冲积河流（古洪水）洪水沉积记录。数据将有助于理解景观和生态系统对极端洪水的反应，并改善人口稠密的沿海地区过去风暴活动和周期性的古森林学和古风暴学重建。该奖项反映了NSF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。

High magnitude riverine floods are an increasingly recognized process shaping landscapes, mobilizing sediment and contaminants and building stratigraphic records. Tropical cyclones are the dominant mechanism that delivers extreme precipitation and produces high magnitude riverine flooding. Hurricane Florence made landfall in North Carolina on Sep 14, 2018 where it stalled and generated heavy precipitation and historic flooding on rivers across the lower Atlantic coastal plain. These floods reshaped floodplains and mobilized a range of contaminants from industries in the region, providing a unique opportunity to study the geomorphic and environmental effects of an extreme flood. The PIs will systematically collect sediment deposited by the flood in the lower reaches of the Pee Dee River system, one of the largest watersheds in the southeastern US, to investigate the lateral and longitudinal patterns of sediment and associated contaminant deposition immediately following flooding caused by a landfalling hurricane. This research will clarify how extreme flood events carry sediments and contaminants from land to sea, a process affecting the health of people and ecosystems along the way. Identifying and quantifying contaminant inputs to Winyah Bay has critical implications for coastal ecosystem management and public health. Findings will be communicated to local stakeholders and decision makers. The project will fund a multidisciplinary team that encompasses geoscientists, environmental scientists, and environmental engineers across a range of career stages. A diverse group of undergraduate and graduate students from Coastal Carolina University and Northeastern University will participate in the proposed activities to gain research experience and develop research activities that can be built into their academic programs.Landfalling hurricanes generating riverine flooding hazards on the Atlantic Coastal Plain affect millions of area residents. This project takes advantage of a rare extreme flood to observe how this type of event shapes the floodplain of an alluvial river system and transports sediment and contaminants from land and point sources to the coastal ocean. The PIs will collect floodwater sediment samples before other processes remove or erode the flood-born deposits. They will analyze sediment characteristics, conduct 7Be dating of sediment to confirm timing of deposition, and measure concentrations of organic (Polycyclic aromatic hydrocarbons; PAHs) and trace metal (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sn, Hg, Pb, and Bi) contaminants in the floodwater sediments. Like flood and contaminant research resulting from Hurricane Harvey (2017), the work is highly relevant and illustrative of the need to track contaminant dispersal as a public health issue. Using both PAHs and the selected trace metals will provide stronger source identification for PAH compounds, e.g., run-off from roads, parking lot sealcoat, or associated with coal combustion. The proposed activities build on an active NSF project (EAR-1804799) supporting PIs Munoz and Shen that develops sedimentary records of flooding on alluvial rivers (paleofloods) by providing a modern analogue of sediment deposition by an extreme flood. Data will aid in understanding landscape and ecosystem responses to extreme flooding and improve paleoflood and paleo-tempestological reconstructions of past storm activity and periodicity in heavily populated coastal regions.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.