Paleohydrological Assessment of Extreme Flooding Events

极端洪水事件的古水文学评估

• 批准号: 2318481
• 负责人: Joseph Zeleznik
• 金额: $ 34.99万
• 依托单位: North Dakota State University Fargo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2318481&HistoricalAwards=false
• 关键词: Paleohydrological; Assessment; Extreme; Flooding; Events

This research project will examine the degree to which major floods can be identified using paleoenvironmental records, thereby lengthening the historical time periods over which flooding can be identified and enhancing capabilities for analyzing relationships among surface hydrology, climate, and other natural and human-related variables. Focusing on the Red River of the North, which separates Minnesota and North Dakota, the investigators will compile data from tree-ring sequences of long-lived trees, timbers from historical buildings, and subfossil logs from alluvial deposits to produce a composite record that spans the last several centuries. These records will facilitate more accurate estimates of the frequency and magnitude of floods prior to the 20th century. The project will increase understanding of the factors that influence flooding over longer time periods, with surrogate records providing data for two or more times the duration of instrument-based flood records. The historical extension of flood records is especially valuable for studying very large floods that occur infrequently. New insights generated through this project can help to determine whether extreme floods on major river systems are becoming more common as natural and human-related factors change in river basins. By demonstrating how natural sources of flood information can contribute to flood mitigation decisions prior to the construction of major infrastructure, this project will reposition paleoflood hydrology within the broader field of hazard preparedness. The investigators will collaborate with U.S. Geological Survey staff at the Dakota Water Science Center to use paleoflood estimates in the assessment of future flood risks. Project results will help those responsible for managing rivers as well as residents and decision makers to evaluate vulnerability to floods and to weigh the potential benefits of proposed infrastructure, such as the construction of a 36-mile, $1.7 billion diversion channel that would redirect floodwaters around the Fargo-Moorhead metropolitan area.This project will determine how the extraordinary 1826 Red River flood documented downstream in Canada in historical accounts also affected the American stretch of the river. Red River floods have caused more than $3.5 billion in direct damages to American communities over the past two decades and have spurred the construction or proposed construction of nearly $2.5 billion in flood mitigation infrastructure. Because the known record of Red River floods only extends back to the late 19th century, other sources of information are needed to estimate the risks of future severe floods. Using an analog approach to compare tree-ring evidence associated with recent major floods with known stage and discharges of older events only present in the tree-ring record, the investigators will produce estimates of the relative magnitudes of earlier floods. For old trees that extend back into the early 19th century or earlier, the maximum stage of past floods will be inferred from the vertical position of anatomical abnormalities along the tree stem. The new paleoflood record for the Red River will enable the investigators to answer questions regarding the synchrony of flooding along the entire reach of the river and to gauge how flooding on the northern Great Plains is related to variability in climate and other environmental factors at local and regional scales.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.

该研究项目将研究使用古环境记录可以识别大洪水的程度，从而延长了可以识别洪水的历史时间段，并增强了分析表面水文，气候以及其他自然和人类相关变量之间关系的能力。 研究人员专注于将明尼苏达州和北达科他州分开的北部河流，将从长寿命的树木，历史建筑物的木材和从冲积矿床中的亚物质日志中编译数据，以产生跨越最后几个世纪的复合记录。 这些记录将有助于更准确地估计20世纪之前洪水的频率和幅度。 该项目将增加对影响较长时间洪水的因素的理解，而替代记录则是基于仪器的洪水记录的两倍或更多倍的数据。 洪水记录的历史扩展对于研究很少发生的大洪水特别有价值。 通过该项目产生的新见解可以帮助确定随着河流盆地的自然和与人相关的因素的变化，主要河流系统的极端洪水是否变得越来越普遍。 通过证明自然洪水信息的来源如何在建设主要基础设施之前有助于减轻洪水的决定，该项目将在更广泛的危险领域重新定位古植物的水文学。 调查人员将与达科他州水科学中心的美国地质调查人员合作，以评估未来的洪水风险来评估古植物的估计。 项目结果将有助于负责管理河流以及居民和决策者评估洪水的脆弱性并权衡拟议基础设施的潜在好处，例如建造36英里英里的17亿美元转移渠道，这些渠道将重新定向在Farogo-Moorhead Metropolitan地区周围的洪水范围，该洪水将如何确定越野河之间的历史悠久的Redriver intercance 1826，河。 在过去的二十年中，红河洪水对美国社区造成了超过35亿美元的直接损害赔偿，并刺激了建设或拟议建设近25亿美元的缓解洪水基础设施。 由于已知的红河洪水记录仅延伸到19世纪后期，因此需要其他信息来源来估计未来严重洪水的风险。 使用模拟方法将养树证据与最近的主要洪水与已知阶段和仅存在的旧事件的排放相关联，研究人员将产生对早期洪水的相对幅度的估计。 对于延伸到19世纪初或更早的老树，将从树茎沿树茎的解剖异常的垂直位置推断出过去洪水的最大阶段。 红河的新古德洛德记录将使调查人员能够回答有关河流整个河流洪水的同步的问题，并衡量北部大平原上的洪水与地方和区域范围的气候和其他环境因素的可变性有关。这一奖项反映了NSF的法定任务，反映了通过评估的范围的范围，这是由Infactiria构成的范围。