Developing Mechanistic Models for Bedrock Erosion at Waterfalls.

开发瀑布基岩侵蚀的机制模型。

• 批准号: 1147381
• 负责人: Michael Lamb
• 金额: $ 27.5万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-15 至 2016-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1147381&HistoricalAwards=false
• 关键词: Developing; Mechanistic; Models; Bedrock; Erosion

The upstream movement of waterfalls controls the shape of many landscapes and sets the rate by which landscapes respond to changes in climate and tectonics. However, we currently lack mechanistic models for waterfall erosion which inhibits our ability to predict landscape response to environmental perturbations. The goal of this project is to fill this knowledge gap through a combination of experiments in an indoor waterfall laboratory and monitoring waterfall processes in nature. The waterfall experiments will be completed in a new state-of-the-art hydraulic and sediment flume at the California Institute of Technology. This work will lead to mathematical theories for the sediment transport capacity and erosion of waterfall plunge pools. The models developed from flume experiments will be tested against sediment transport data that we will collect at an active waterfall in the San Gabriel Mountains, CA, and over longer timescales against a new database of waterfall retreat rates compiled from previous studies. In addition to deriving and testing models for waterfall retreat, our work will aid understanding sediment routing and storage in mountain streams because waterfall plunge pools are natural temporary sediment sinks, with importance for mitigating river flood hazards and understanding habitats of aquatic organisms that depend on pools in summer months. A focus of this proposal is an integrated research and education program. Waterfalls are ubiquitous and awe-inspiring landforms in the natural landscape; they provide a great medium through which to interest students and the public in issues of erosion and sedimentation, as well as landscape evolution. The proposed educational program includes mentoring summer undergraduate research fellows and PhD students who will be directly involved with the research. Through the Caltech Summer Undergraduate Research Fellowship program, undergraduate students will define and develop a project, write research proposals, carry out subsets of the laboratory and field work, submit a technical paper, and give an oral presentation at a symposium modeled on a professional technical meeting. Outreach events will be focused on tours, classroom visits, and field excursions for students and teachers in the Pasadena Unified School District (P.U.S.D.), a district where the majority of students are from groups under-represented in geosciences.

瀑布的上游运动控制着许多景观的形状，并决定了景观对气候和构造变化的反应速度。然而，目前我们缺乏瀑布侵蚀的机械模型，这限制了我们预测景观对环境扰动的响应的能力。这个项目的目标是通过室内瀑布实验室的实验和监测自然界中的瀑布过程来填补这一知识空白。瀑布实验将在加州理工学院最先进的水力和泥沙水槽中完成。这项工作将为瀑布消力池的输沙能力和冲刷提供数学理论。通过水槽实验开发的模型将与我们将在加利福尼亚州圣加布里埃尔山脉的一个活跃瀑布收集的泥沙输送数据进行测试，并将在更长的时间尺度上与根据先前研究汇编的新的瀑布退化率数据库进行测试。除了推导和测试瀑布后退模型外，我们的工作还将有助于了解山溪中的泥沙路线和储存，因为瀑布凹陷水池是天然的临时泥沙汇，对于缓解河流洪水风险和了解夏季依赖水池的水生生物的栖息地具有重要意义。这项提议的重点是一个综合的研究和教育计划。瀑布是自然景观中无处不在的令人敬畏的地貌；它们提供了一个很好的媒介，通过它来引起学生和公众对侵蚀和沉积问题以及景观演变的兴趣。拟议的教育计划包括指导暑期本科生研究员和博士生，他们将直接参与研究。通过加州理工学院夏季本科生研究奖学金计划，本科生将定义和开发一个项目，撰写研究提案，开展实验室和实地工作的子集，提交一篇技术论文，并在模拟专业技术会议的研讨会上进行口头陈述。外展活动将侧重于帕萨迪纳联合学区(P.S.D.)的学生和教师的参观、课堂访问和实地考察，该学区的大多数学生来自地球科学中代表性不足的群体。