EAR-PF: Impact of flooding intensity on levee development and dynamics

EAR-PF：洪水强度对堤坝发育和动态的影响

• 批准号: 2052844
• 负责人: Eric Barefoot
• 金额: $ 17.4万
• 依托单位: Barefoot, Eric A
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2052844&HistoricalAwards=false
• 关键词: EAR; PF; Impact; flooding; intensity

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Dr. Eric Barefoot has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at Indiana University. Dr. Barefoot will study flooding, a significant natural hazard that threatens critical infrastructure and communities in the US and across the world. Artificial embankments (or dikes) along river corridors are often constructed to reduce flooding hazards and these engineering projects often take advantage of natural levees on the floodplain. Levees form next to a river channel when the river floods and sediment spreads out away from the river. Because levee formation correlates poorly with river attributes, it remains challenging to predict where and when levees will form. This project seeks to test a new hypothesis: that the intensity of floods is a key control on levee formation. By combining analysis of floodplains across the State of Indiana with monitoring on the Lower Mississippi River, this project will determine the importance of flood intensity for levee formation. Dr. Barefoot will also identify processes by which sediment is transported on river floodplains during floods. These research outcomes will be coupled with an educational outreach plan that focuses on engaging public-school educators to produce new curriculum focused on flood hazards and sustainability in Indiana. Additionally, this project will bolster STEM engagement for LGBTQ+ undergraduate students through local field-based research opportunities. Natural levees form and develop during overbank flow, when sediment-laden water decants from the river, and deposits adjacent to the channel. The pattern of sediment deposition is controlled by water surface gradients across the inundated floodplain. The orientation and mag- nitude of water surface gradients are hypothesized to depend on flooding intensity; operationally defined here as the coefficient of variation of discharge (CVQ). However, the impact of flooding intensity on floodplain deposition is poorly constrained because direct observations of co-evolving floodplain topography and inundation hydraulics are scarce. This project will quantify the impact of flooding intensity on floodplain inundation patterns and analyze how resulting water surface gradients influence levee formation and development. This research will combine repeat lidar datasets with field surveys and sedimentological observations on floodplains in Indiana, USA, to compare levee morphology and composition spanning a range of historical flooding intensities. To link flooding intensity and sediment dispersal in a mechanistic framework, a complementary case study will be conducted in an end-member locality typified by low flooding intensity. In-situ measurements of water surface elevation and velocity during annual overbank conditions in an engineered section of the Mississippi River will be paired with repeat lidar topography surveys to couple inundation hydraulics with topographic evolution. New insights from this project will fill a critical research need because intensified flooding due to contemporary climate change threatens sustainability of river corridors. The scientific outcomes will inform land management strategies while also driving fundamental advances in sedimentology and geomorphology.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.

该奖项的全部或部分资金根据《2021 年美国救援计划法案》（公法 117-2）提供。 Eric Barefoot 已获得 NSF EAR 博士后奖学金，用于在印第安纳大学开展研究和教育计划。 赤脚博士将研究洪水，这是一种严重的自然灾害，威胁着美国和世界各地的关键基础设施和社区。沿着河流廊道修建人工堤坝（或堤坝）通常是为了减少洪水灾害，这些工程项目通常利用洪泛区的天然堤坝。当河流泛滥且沉积物远离河流时，堤坝就会在河道旁边形成。由于堤坝的形成与河流属性的相关性较差，因此预测堤坝形成的地点和时间仍然具有挑战性。该项目旨在检验一个新假设：洪水强度是堤坝形成的关键控制因素。通过将印第安纳州洪泛区的分析与密西西比河下游的监测相结合，该项目将确定洪水强度对堤坝形成的重要性。赤脚博士还将确定洪水期间沉积物在河漫滩上输送的过程。这些研究成果将与一项教育外展计划相结合，该计划的重点是让公立学校教育工作者参与制定以印第安纳州洪水灾害和可持续性为重点的新课程。此外，该项目还将通过当地实地研究机会，促进 LGBTQ+ 本科生对 STEM 的参与。当含有沉积物的水从河流中倾析出来并沉积在河道附近时，天然堤坝在漫滩流动过程中形成和发展。沉积物沉积的模式由淹没泛滥平原的水面梯度控制。假设水面梯度的方向和大小取决于洪水强度；这里在操作上定义为流量变异系数（CVQ）。然而，洪水强度对洪泛区沉积的影响很少受到限制，因为对共同演化的洪泛区地形和洪水水力学的直接观测很少。该项目将量化洪水强度对洪泛区洪水模式的影响，并分析由此产生的水面梯度如何影响堤坝的形成和发展。这项研究将重复激光雷达数据集与美国印第安纳州洪泛区的现场调查和沉积学观测相结合，以比较一系列历史洪水强度范围内的堤坝形态和成分。为了在机械框架中将洪水强度和沉积物扩散联系起来，将在以低洪水强度为代表的端部成员地区进行补充案例研究。密西西比河工程河段每年漫滩情况下的水面高程和流速的现场测量将与重复的激光雷达地形测量相结合，将洪水水力学与地形演变结合起来。该项目的新见解将满足关键的研究需求，因为当代气候变化导致的洪水加剧威胁着河流走廊的可持续性。科学成果将为土地管理策略提供信息，同时也推动沉积学和地貌学的根本性进步。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。