NSF-BSF: Monitoring bedload transport: Advancing seismic and acoustic surrogate methods in ephemeral channels

NSF-BSF：监测沉积物迁移：推进短暂通道中的地震和声学替代方法

基本信息

批准号：
1852794
负责人：
Daniel Cadol
金额：
$ 44.74万
依托单位：
New Mexico Institute of Mining and Technology
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-06-01 至 2025-05-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1852794&HistoricalAwards=false
关键词：
NSF BSF Monitoring bedload transport

项目摘要

The flow of water in rivers, especially during floods, transports sand, gravel, rocks, and even boulders. This movement of particles (bedload transport) shapes the river channel itself, influences the erosion of bed and banks, and helps give shape to the broader landscape. Measuring bedload transport is difficult, though, because it changes rapidly in both space and time and can be quite dangerous to collect data during the high-energy flood events when most material moves. This project will experiment with new measurement techniques that can be done safely outside of the river channel. The investigators will compare the vibration and sound energy collected by seismic sensors placed near the river bank with direct measurements of bedload transport collected by physical samplers set into the riverbed. Sampling will take place on two ephemeral streams in semi-arid regions of New Mexico, USA and Israel, streams which are usually dry, but which transport a great deal of material when they do flow during flash floods. The data generated by this project will be used to test and expand models of how bedload movement generates seismic energy, which will benefit a wide audience of scientists who want non-invasive methods to monitor river and bedload processes. In addition, because understanding how bedload moves is critical for river management, the results will assist water management agencies such as the US Bureau of Reclamation and the US Army Corp of Engineers. This project also trains diverse US and international students in hydrology, seismology, and geomorphology, with a project team that includes experts from the US, Israel, France, and Germany. Bedload flux is fundamental to river dynamics and landscape evolution, yet the collection of representative measurements of this key parameter is inhibited by its spatial and temporal variability as well as the challenge of sampling in high-energy environments (for example, desert flash floods) without altering transport. Surrogate methods are a promising approach, yet calibration remains a challenge, and the lower grain size limit of detection is uncertain. This project will take advantage of already-built infrastructure to directly measure bedload transport, use these data to calibrate acoustic surrogates, and then use both of these to calibrate and test seismic monitoring of bedload transport. This approach will provide vital field data to enable the advance of fluvial seismology and sediment transport modeling in drylands by testing theoretical models of bedload seismic energy generation. The study sites are ephemeral channels in semi-arid regions of New Mexico, USA, and Israel, at which riverbed slot samplers will monitor bedload flux at multiple locations across the channel. These data will be used to calibrate collocated pipe microphones that collect data throughout the flood. An array of ~ 70-80 short period, 3-component geophone seismometers will collect seismic data near the channel, which will then be compared with the direct and acoustic bedload data. In subsequent years, seismometers will also be deployed along the channel system to study the movement of bedload throughout an entire catchment. The data collection and analysis will refine the overarching theoretical framework of understanding for the transport of sand-rich gravel in semiarid and arid regions of our planet.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.

河流中的水流，尤其是在洪水期间，运输沙子，砾石，岩石，甚至是巨石。颗粒（床负载运输）的这种运动塑造了河道本身，影响床和河岸的侵蚀，并有助于形成更广阔的景观。但是，很难测量床负载的运输，因为它在时空和时间上都迅速变化，并且在大多数材料移动时，在高能洪水事件中收集数据可能非常危险。该项目将尝试在河道外安全完成的新测量技术。调查人员将比较位于河岸附近的地震传感器收集的振动和声能，并直接测量设置在河床中的物理采样器收集的床负载运输。采样将在新墨西哥州，美国和以色列的半干旱地区的两个短暂溪流上进行，这些流通常干燥，但在山洪泛滥期间流动时会运输大量材料。该项目生成的数据将用于测试和扩展床载运方式如何产生地震能量的模型，这将使希望有非侵入性方法监视河流和床载流程的大量科学家受益。此外，由于了解卧床的移动对于河流管理至关重要，因此结果将有助于水管理机构，例如美国开垦局和美国陆军工程师。该项目还培训了包括美国，以色列，法国和德国的专家的项目团队，培训了我们和国际水文学，地震学和地貌学的各种各样的学生。床负载通量是河流动力学和景观演化的基础，但是该关键参数的代表性测量值受到其空间和时间变异性的抑制，以及在高能环境中采样（例如沙漠洪水泛滥）在没有改变运输的情况下进行采样的挑战。替代方法是一种有希望的方法，但校准仍然是一个挑战，较低的晶粒尺寸检测限制尚不确定。该项目将利用已经建立的基础架构直接测量床负荷运输，使用这些数据来校准声学替代物，然后使用两者来校准和测试对床负载传输的地震监测。这种方法将提供重要的现场数据，以通过测试床载地震能量产生理论模型，从而实现河流地震学和沉积物传输建模的发展。研究地点是新墨西哥州，美国和以色列半干旱地区的短暂通道，在该地区，河床插槽采样器将在整个通道的多个位置监视床位通量。这些数据将用于校准共处的管道麦克风，以在整个洪水中收集数据。〜70-80短期的阵列3组分地震仪将在通道附近收集地震数据，然后将其与直接和声学的床载数据进行比较。在随后的几年中，也将沿着通道系统部署地震仪，以研究整个集水区的床载流动。数据收集和分析将完善地球上半干旱和干旱地区的富含沙砾石运输的总体理论框架。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来进行评估的。