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得到承认的过程，它塑造地貌、调动沉积物和污染物并建立地层记录。热带气旋是造成极端降水和高强度河水泛滥的主要机制。飓风佛罗伦萨于2018年9月14日在北卡罗来纳州登陆，随后停滞不前，并在大西洋下游平原的河流上产生了强降水和历史性洪水。这些洪水重塑了泛滥平原，并调动了该地区工业中的一系列污染物，为研究极端洪水对地貌和环境的影响提供了独特的机会。PIS将系统地收集洪水在皮迪河系统下游沉积的沉积物，皮迪河系统是美国东南部最大的分水岭之一，以调查登陆飓风造成的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带到海洋，这是一个沿途影响人类和生态系统健康的过程。确定和量化进入Winyah Bay的污染物输入对沿海生态系统管理和公共卫生具有重要影响。调查结果将传达给当地利益攸关方和决策者。该项目将资助一个由地球科学家、环境科学家和环境工程师组成的跨职业阶段的多学科团队。来自卡罗莱纳海岸大学和东北大学的一群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，并开发可以纳入他们的学术计划的研究活动。在大西洋海岸平原造成河流洪水危害的登陆飓风影响到数百万地区的居民。该项目利用一场罕见的极端洪水，观察这类事件如何塑造冲积河流系统的泛滥平原，并将沉积物和污染物从陆地和点源输送到沿海海洋。在其他工序移走或侵蚀洪水产生的沉积物之前，私人投资者会收集洪水沉积物样本。他们将分析沉积物特征，对沉积物进行7Be测年以确定沉积时间，并测量洪水沉积物中有机(多环芳烃；PAHs)和痕量金属(V、铬、锰、铁、钴、镍、铜、锌、砷、硒、银、镉、锡、汞、铅和铋)污染物的浓度。与飓风哈维(2017)造成的洪水和污染物研究一样，这项工作具有很高的相关性，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。同时使用多环芳烃和选定的痕量金属将为多环芳烃化合物提供更强的来源识别，例如道路径流、停车场废气或与煤炭燃烧有关的径流。拟议的活动建立在一个正在进行的国家科学基金会项目(EAR-1804799)的基础上，该项目支持Pis Munoz和Sheni，该项目通过提供极端洪水造成的泥沙沉积的现代模拟，开发冲积河流(古洪水)上洪水的沉积记录。数据将有助于了解景观和生态系统对极端洪水的反应，并改进对人口稠密的沿海地区过去风暴活动和周期性的古洪水和古风暴重建。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.