EAR-PF: Quantifying the effects of flow transience on sediment transport

EAR-PF：量化流动瞬变对沉积物输送的影响

• 批准号: 1349776
• 负责人: Colin Phillips
• 金额: $ 8.7万
• 依托单位: Phillips Colin B
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1349776&HistoricalAwards=false
• 关键词: EAR; PF; Quantifying; effects; flow

Dr. Colin Phillips has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out a research and educational outreach plan at the University of Minnesota. He will investigate the process of gravel transport in response to transient and intermittent flooding. Gravel rivers represent the rate limiting step in the incision of mountains and also provide critical habitat and breeding grounds to numerous aquatic species. These experiments will form the basis for understanding how potential changes in climate and land use will affect gravel streams. In addition these experiments will provide a quantitative framework for stream managers regulating flow releases below dams and stream restoration projects. The results from these experiments will be turned into interactive online tools for stream restoration practitioners. Furthermore, the knowledge gained from this project will be transferred to young scientists through classes and experiments during the National Center for Earth Surface Dynamics 2 (NCED2) Summer Institute, and to future young scientists by collaborating with NCED2 REU students.A large majority of our understanding of gravel river dynamics comes from flume experiments under constant or slowly varying floods. Many of the theories developed under steady flow provide reasonable predictions of the dynamics of gravel rivers when averaged over numerous floods, however due to the stochastic nature of sediment transport it remains unclear whether these predictions break down due to flow unsteadiness or granular phenomena. Through the use of laboratory experiments he will test the relative importance of flood shape and sequence to determine how an unsteady flow drives sediment transport. This project will compare the dynamics of gravel transport at the particle level through the tracking of several populations of marked particles under a variety of single and sequences of flows of varying magnitude and duration, but equivalent impulse (time-integrated momentum above the threshold of particle motion).

科林·菲利普斯博士获得了美国国家科学基金会地球科学博士后奖学金，以在明尼苏达大学开展研究和教育推广计划。他将调查应对短暂和间歇性洪水的砾石运输过程。砾石河代表了山脉切割的速度限制步骤，也为许多水生物种提供了重要的栖息地和繁殖地。这些实验将为了解气候和土地利用的潜在变化将如何影响砾石流奠定基础。此外，这些实验将为河流管理者调节水坝和河流恢复项目下方的流量释放提供定量框架。这些实验的结果将转化为流恢复从业者的交互式在线工具。此外，从该项目中获得的知识将通过国家地表动力学中心 2 (NCED2) 夏季学院期间的课程和实验传授给年轻科学家，并通过与 NCED2 REU 学生合作传授给未来的年轻科学家。对砾石河动力学的了解来自于恒定或缓慢变化的洪水下的水槽实验。在稳定流下发展的许多理论提供了对砾石河动态的合理预测，当对多次洪水进行平均时，然而，由于泥沙输送的随机性，目前还不清楚这些预测是否由于流动不稳定或颗粒现象而失效。通过实验室实验，他将测试洪水形状和序列的相对重要性，以确定不稳定的水流如何驱动沉积物输送。该项目将通过跟踪不同大小和持续时间的各种单一流和序列流下的多个标记颗粒群体，比较颗粒水平上砾石传输的动力学，但等效冲量（高于颗粒阈值的时间积分动量）运动）。