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

• 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

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，特别是在洪水期间，会输送沙子、砾石、岩石，甚至巨石。这种颗粒的运动（底质输送）塑造了河道本身，影响河床和河岸的侵蚀，并有助于塑造更广阔的景观。然而，测量底土输送很困难，因为它在空间和时间上都迅速变化，并且在大多数物质移动的高能洪水事件期间收集数据可能非常危险。该项目将试验新的测量技术，这些技术可以在河道之外安全地进行。研究人员将把放置在河岸附近的地震传感器收集的振动和声能与设置在河床中的物理采样器收集的底土输送的直接测量结果进行比较。采样将在美国新墨西哥州和以色列半干旱地区的两条短暂溪流上进行，这些溪流通常是干燥的，但在山洪爆发期间流动时会输送大量物质。该项目生成的数据将用于测试和扩展底泥运动如何产生地震能量的模型，这将使​​广大需要非侵入性方法监测河流和底泥过程的科学家受益。此外，由于了解沉积物如何移动对于河流管理至关重要，因此研究结果将有助于美国垦务局和美国陆军工程兵团等水资源管理机构。该项目还对水文、地震学和地貌学领域的美国和国际学生进行培训，项目团队包括来自美国、以色列、法国和德国的专家。 河床流量是河流动力学和景观演化的基础，但这一关键参数的代表性测量值的收集受到其空间和时间变化以及在高能环境（例如沙漠山洪）中采样的挑战的限制，而无需改变运输。替代方法是一种有前途的方法，但校准仍然是一个挑战，并且检测的粒度下限是不确定的。该项目将利用已建成的基础设施直接测量床土输送，使用这些数据校准声学替代物，然后使用这两者来校准和测试床土输送的地震监测。该方法将提供重要的现场数据，通过测试床载地震能量生成的理论模型，推动旱地河流地震学和沉积物输送模型的发展。研究地点是新墨西哥州、美国和以色列半干旱地区的临时河道，河床狭缝采样器将监测河道上多个地点的底泥通量。这些数据将用于校准在整个洪水过程中收集数据的并置管道麦克风。大约 70-80 个短周期、3 分量地震检波器的阵列将收集通道附近的地震数据，然后将其与直接和声学沉积物数据进行比较。在接下来的几年中，地震仪也将沿河道系统部署，以研究整个流域的床质运动。数据收集和分析将完善理解地球半干旱和干旱地区富沙砾石运输的总体理论框架。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值进行评估，被认为值得支持以及更广泛的影响审查标准。

项目成果

Direct, continuous measurements of ultra-high sediment fluxes in a sandy gravel-bed ephemeral river

直接、连续测量砂砾石床短命河流中的超高沉积通量

• DOI: 10.1016/j.geomorph.2021.107682
• 发表时间: 2021-03-04
• 期刊: Geomorphology
• 影响因子: 3.9
• 作者: K. Stark;D. Cadol;D. Varyu;J. Laronne
• 通讯作者: J. Laronne