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重大洪水的程度，从而延长可以识别洪水的历史时间段，并提高分析地表水文，气候和其他自然和人类相关变量之间关系的能力。 以分隔明尼苏达州和北达科他州的北部红河为重点，调查人员将从长寿树木的年轮序列、历史建筑的木材和冲积层的亚化石日志中收集数据，以产生跨越过去几个世纪的复合记录。 这些记录将有助于更准确地估计世纪之前洪水的频率和规模。 该项目将增加对影响较长时期洪水的因素的了解，替代记录提供的数据持续时间是基于仪器的洪水记录的两倍或两倍以上。 洪水记录的历史延伸对于研究罕见的特大洪水特别有价值。 通过该项目产生的新见解可以帮助确定主要河流系统的极端洪水是否随着河流流域的自然和人为因素的变化而变得越来越普遍。 通过展示洪水信息的自然来源如何有助于在建设主要基础设施之前做出防洪决策，该项目将在更广泛的防灾领域内重新定位古森林水文学。 研究人员将与达科他州水科学中心的美国地质调查局工作人员合作，利用古植被估计来评估未来的洪水风险。 项目成果将帮助负责河流管理的人员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效益，例如建造一条36英里长的，耗资17亿美元的引水渠将使法戈河周围的洪水改道，穆尔黑德大都市区。这个项目将确定如何非凡的1826年红河洪水记录在加拿大下游的历史帐户也影响了美国的延伸河流。 在过去的二十年里，红河洪水给美国社区造成了超过35亿美元的直接损失，并促使人们建造或拟议建造近25亿美元的防洪基础设施。 由于已知的红河洪水记录只能追溯到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。 使用类似的方法来比较与最近的大洪水有关的树木年轮证据与已知的阶段和排放的旧事件只存在于树木年轮记录，调查人员将产生早期洪水的相对大小的估计。 对于那些可以追溯到世纪早期或更早的古树，将从树干沿着解剖异常的垂直位置推断过去洪水的最高阶段。 红河新的古森林记录将使研究人员能够回答有关洪水沿着整个河段的同步性问题，并衡量北方大平原的洪水如何与当地和区域尺度的气候和其他环境因素的变化有关。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识产权进行评估来支持。优点和更广泛的影响审查标准。