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.

该奖项全部或部分根据2021年美国救援计划法案（公法117-2）资助。Eric Barefoot博士已获得NSF博士后奖学金，在印第安纳州大学开展研究和教育计划。 赤脚博士将研究洪水，这是一种威胁美国和世界各地关键基础设施和社区的重大自然灾害。通常沿沿着河道建造人工堤坝（或堤防）以减少洪水危害，这些工程项目通常利用洪泛平原上的天然堤坝。当河水泛滥，沉积物扩散到远离河流的地方时，堤坝就在河道旁边形成了。由于堤坝的形成与河流属性的相关性很差，因此预测堤坝何时何地形成仍然具有挑战性。该项目试图验证一个新的假设：洪水强度是堤坝形成的关键控制因素。通过结合对印第安纳州洪泛区的分析和对密西西比河下游的监测，本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流洪泛区运输的过程。这些研究成果将与一项教育推广计划相结合，该计划的重点是让公立学校的教育工作者参与制作新的课程，重点是印第安纳州的洪水灾害和可持续性。此外，该项目将通过当地实地研究机会，加强LGBTQ+本科生的STEM参与。天然堤坝的形成和发展过程中溢出流，当泥沙水从河流，并沉积附近的渠道。沉积物的沉积模式是由淹没洪泛区的水面梯度控制的。假设水面梯度的方向和大小取决于洪水强度;此处操作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受到很大的限制，因为共同发展的洪泛区地形和淹没水力学的直接观测是稀缺的。该项目将量化洪水强度对洪泛区淹没模式的影响，并分析由此产生的水面梯度如何影响堤坝的形成和发展。这项研究将结合联合收割机重复激光雷达数据集与实地调查和沉积学观察漫滩在印第安纳州，美国，比较堤防形态和组成跨越一系列的历史洪水强度。为了将洪水强度和沉积物扩散联系在一个机械框架中，将在一个以低洪水强度为代表的端员地区进行补充案例研究。在密西西比河工程段每年的漫滩条件下，将对水面高程和流速进行现场测量，并与重复的激光雷达地形测量相结合，以将洪水水力学与地形演变相结合。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。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。