A mechanistic and predictive understanding of temporal variations in the onset of sediment motion

对沉积物运动开始时间变化的机械和预测理解

• 批准号: 1921790
• 负责人: Elowyn Yager
• 金额: $ 34.9万
• 依托单位: Regents of the University of Idaho
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1921790&HistoricalAwards=false
• 关键词: mechanistic; predictive; understanding; temporal; variations

The movement of rocks along river beds, called sediment transport, is essential for estimating river channel stability and therefore risks to infrastructure and human lives during floods. Sediment transport predictions are also used to help restore rivers for numerous aquatic species. Despite its importance, sediment transport is notoriously difficult to predict, and this project will investigate how changes in river bed structure (e.g. rock arrangement) influences sediment transport. Such information will then be used to improve sediment transport predictions. Through a collaboration with artists, sculptures will be temporarily placed in rivers to serve as 1) flow obstructions (e.g. boulders and wood) that provide habitat for a range of fish species, and 2) public outreach installations through signs posted near the sculptures with links to websites containing information and videos about the science of this project. Errors in sediment transport predictions can be partly explained by the common assumption that the onset of sediment motion always occurs at the same flow magnitude in a given river. Large temporal changes in the onset of sediment motion can occur because of variations in the channel bed structure. The goals of this proposal are to better understand these temporal changes in bed structure and to use this understanding to accurately predict the onset of sediment motion. Laboratory experiments and a mechanistic theory are used to identify and quantify the channel bed parameters that control variations in the onset of sediment motion. This theory will be tested using field measurements in a well instrumented channel and could replace the often arbitrary choice of a single flow magnitude that causes the start of sediment movement.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.

岩石沿着河床的运动（称为沉积物运输）对于估算河道稳定性至关重要，因此在洪水期间对基础设施和人类生命的风险。 沉积物传输预测还用于帮助恢复众多水生植物的河流。尽管它很重要，但众所周知，很难预测沉积物的运输，该项目将研究河床结构的变化（例如岩石布置）如何影响沉积物的运输。然后，此类信息将用于改善沉积物传输预测。通过与艺术家的合作，雕塑将临时放置在河流中，以用作1）流动障碍（例如巨石和木材），这些流动障碍物（例如，巨石和木材）为各种鱼类提供了栖息地，以及2）通过在雕塑附近发布的标志，链接到包含有关该项目科学的信息和视频的网站的链接。在给定河流中，沉积物运动的发作总是在相同的流量幅度出现，可以部分解释沉积物传输预测中的误差。由于通道床结构的变化，可能发生沉积物运动开始的时间变化。该建议的目标是更好地了解床结构中的这些时间变化，并利用这种理解来准确预测沉积物运动的发作。 实验室实验和机械理论用于识别和量化控制沉积物运动开始变化的通道床参数。 该理论将使用仪器通道中的现场测量进行测试，并可以替代导致沉积物运动开始的单个流量幅度通常任意选择的选择。该奖项反映了NSF的法定任务，并被认为值得通过基金会的知识分子优点和更广泛的影响标准通过评估来进行评估。