River Responses to Natural and Human-induced Changes in Sediment Supply

河流对自然和人为引起的沉积物供应变化的响应

• 批准号: 1951469
• 负责人: Francis Magilligan
• 金额: $ 42.75万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951469&HistoricalAwards=false
• 关键词: River; Responses; Natural; Human; induced

This project explores the processes and outcomes of river responses to both natural and human-induced changes in sediment supply to better develop predictive models of channel morphlogic adjustments and the mechanisms of sediment transport. Rivers reflect and respond to changes in streamflow and sediment supply striving to maintain equilibrium by mutually adjusting an array of channel properties. Yet, recent research reveals that the type and magnitude of these responses is conditioned in unknown ways by variations in sediment supply. The investigators will use stream reaches at and below existing/removed dams that decrease/increase sediment supply as an experimental design to capture these potential responses. With its focus on dams and dam removal, project outcomes will be relevant to watershed managers, especially as the nation’s existing dam infrastructure continues to age, posing significant environmental, social, and economic risks. This project will recruit diverse students from underrepresented groups. Through articles and presentations at conferences and public meetings, results will be disseminated to a broad array of scientists and regional stakeholders.The overarching goal of this project is to quantify the channel morphologic evolution to transient and/or sustained changes in sediment supply and to demonstrate how morphologic evolution conditions hydraulic properties and subsequent sediment transport. The investigators will utilize a research design that is based on detailed geospatial field mapping and channel surveying combined with monitoring the mobility of gravel clasts tagged with radio-frequency identification (RFID) tracers and with embedded accelerometers to quantify the variation in bankfull hydraulic properties, threshold stream power, and bed architecture in response to changes (both positive and negative) in sediment supply. By taking advantage of the natural experiments provided by both dam emplacement and removal, the research will improve our understanding of channel evolution following a disturbance and thereby advance our theoretical understanding of fundamental river processes that can be applied in other geomorphic settings. The broadly disseminated results are essential for river restoration, with implications for both nature and societyThis 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.

该项目探讨了河流对自然和人为泥沙供应变化的响应过程和结果，以更好地开发河道形态调整和泥沙输运机制的预测模型。河流反映并响应水流和泥沙供给的变化，通过相互调节一系列河道特性来维持平衡。然而，最近的研究表明，这些响应的类型和幅度是以未知的方式由沉积物供应的变化。研究人员将使用现有/拆除的水坝及其下方的河流河段，这些水坝减少/增加沉积物供应，作为一种实验设计，以捕捉这些潜在的反应。由于其重点是大坝和大坝拆除，项目成果将与流域管理者有关，特别是随着国家现有的大坝基础设施继续老化，造成重大的环境，社会和经济风险。该项目将从代表性不足的群体中招募不同的学生。通过在会议和公开会议上的文章和演讲，结果将传播给广泛的科学家和区域利益相关者。该项目的总体目标是量化河道形态演变对沉积物供应的瞬时和/或持续变化的影响，并展示形态演变如何影响水力特性和随后的沉积物输送。调查人员将利用一个研究设计，该设计是基于详细的地理空间实地测绘和信道测量，结合监测砾石碎屑的流动性，标记有射频识别（RFID）示踪剂和嵌入式加速度计，以量化的变化，在满滩水力特性，阈值流功率，和床结构，以响应沉积物供应的变化（积极和消极）。通过利用大坝安置和拆除提供的自然实验，研究将提高我们对扰动后河道演变的理解，从而推进我们对可应用于其他地貌环境的基本河流过程的理论理解。广泛传播的结果对于河流恢复至关重要，对自然和社会都有影响。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。

项目成果

A mechanistic understanding of channel evolution following dam removal

大坝拆除后河道演变的机制理解

• DOI: 10.1016/j.geomorph.2021.107971
• 发表时间: 2021
• 期刊: Geomorphology
• 影响因子: 3.9
• 作者: Fields, Jordan;Renshaw, Carl;Magilligan, Francis;Dethier, Evan;Rossi, Rebecca
• 通讯作者: Rossi, Rebecca

Impact of stream power gradients on storage of sediment and carbon on channel margins and floodplains

河流功率梯度对河道边缘和洪泛区沉积物和碳储存的影响

• DOI: 10.1130/g50339.1
• 发表时间: 2022
• 期刊: Geology
• 影响因子: 5.8
• 作者: Gartner, John D.;Renshaw, Carl E.;Landis, Joshua;Magilligan, Francis J.
• 通讯作者: Magilligan, Francis J.