CAREER: A mechanistic understanding of sediment transport in mountain streams with applications in river restoration and science education

职业：对山间溪流中沉积物输送的机械理解及其在河流恢复和科学教育中的应用

• 批准号: 0847799
• 负责人: Elowyn Yager
• 金额: $ 45.5万
• 依托单位: Regents of the University of Idaho
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0847799&HistoricalAwards=false
• 关键词: CAREER; mechanistic; understanding; sediment; transport

In mountainous drainage basins, steep channels (gradients of 3-20%) occupy the majority of the total channel length and influence the downstream delivery of sediment and water to metropolitan areas and hydropower facilities. The volume and grain sizes of sediment supplied from these streams also impact the success of downstream river restoration projects. Basin-scale sediment transport predictions are needed in restoration design to account for the effect of sediment supply on aquatic habitat, water quality, and channel stability. Most sediment transport equations are based on empirical fits to data measured at the reach-scale, do not include the mechanics of grain motion, and were developed for lower-gradient channels. It is hypothesized that bedload transport equations for steep, rough streams need to include: 1) the range of turbulence and grain properties that control the initiation of grain motion, 2) the spatial variability in stresses and bedload transport rates on patches, and 3) the effect of temporal and spatial variations in sediment supply. Flume experiments will be used to test this hypothesis, further elucidate the interaction between turbulence and bedload transport, and inform theoretical and empirical models that predict sediment flux at the reach scale. Such models will be tested in local and international field locations and will transform predictions of landscape evolution and river restoration design by providing accurate and mechanistic estimates of sediment flux in steep streams. The intellectual merit of this research is a fundamental and predictive understanding of the processes that control turbulence and sediment transport in steep streams. The framework of sediment transport and river restoration will be used to educate graduate, undergraduate, and K-12 students on the importance of water resources and functioning stream ecosystems. Four education objectives are proposed: 1) a series of graduate student classes that develop critical thinking, scientific writing, and interdisciplinary team skills, 2) international research experience for undergraduate and graduate students, 3) programs to educate K-12 students on river processes, and 4) a new Women in Science Camp that encourages young women to enter careers in math, science, and engineering.

在山区排水盆中，陡峭的通道（3-20％的梯度）占总通道长度的大部分，并影响了沉积物和水向大都市地区和水力发电设施的下游输送。 这些流提供的沉积物的体积和谷物尺寸也影响了下游河流恢复项目的成功。 恢复设计中需要进行盆地规模的沉积物传输预测，以说明沉积物供应对水生栖息地，水质和渠道稳定性的影响。大多数沉积物传输方程基于在覆盖范围内测得的数据的经验拟合，不包括晶粒运动的机制，并且是针对较低梯度通道开发的。 假设陡峭，粗糙的溪流的床负载方程需要包括：1）控制谷物运动开始的湍流和谷物特性的范围，2）2）应力和床上载荷速率的空间变化，以及3）泥沙供应中时间和空间变化的效果。 Flume实验将用于检验这一假设，进一步阐明了湍流和床载运输之间的相互作用，并为预测到达量表的沉积物通量提供了理论和经验模型。 此类模型将在本地和国际现场的位置进行测试，并通过提供陡峭溪流中沉积物通量的准确和机械估计来改变景观演化和河流恢复设计的预测。 这项研究的智力优点是对控制陡峭溪流中湍流和沉积物运输的过程的基本和预测的理解。沉积物运输和河流修复的框架将用于教育研究生，本科生和K-12学生关于水资源和运作溪流生态系统的重要性。提出了四个教育目标：1）一系列的研究生课程，发展批判性思维，科学写作和跨学科的团队技能，2）针对本科生和研究生的国际研究经验，3）课程，向K-12学生教育有关河流过程的计划，以及4）4）新女性在科学训练营中鼓励年轻女性从事数学，科学和工程学的职业生涯。