Collaborative Research: Where does the water go: Improving understanding of stream-aquifer-atmosphere interactions around Beaver Dam Analogues

在干旱的美国西部，地下水与地表水的相互作用在历史上一直受到海狸的影响，海狸坝储存并将水重新引导到洪泛区。随着海狸数量的减少，当地市政当局、州政府机构和私人土地所有者一直在安装比弗坝类似物（BDA），这是一种模仿天然海狸坝形式的河流恢复结构，位于海狸较少的河流河段。由于其简单性和预期的好处，BDA正在美国西部获得广泛的关注和实施，尽管缺乏明确的科学数据来评估其对河段尺度水文的影响。 拟议项目旨在解决这一知识空白，通过监测位于美国怀俄明州的一个包含多个BDA的研究地点，确定BDA改变地下水和地表水水位、地下水-地表水交换和蒸散的程度。 该项目将与拥有和管理该研究基地的怀俄明州大自然保护协会（TNC-WY）密切合作。 虽然拟议的工作旨在提高对BDA部署背景下水文过程的理解，但观测结果也将为与BDA相关的几个管理目标提供信息（包括降低流速，将河道重新连接到洪泛区，以及支持野生动物栖息地和牛饲料的河岸植被）。 调查人员将与TNC-WY密切合作，评估这些管理目标，与当地和区域从业人员和利益相关者分享调查结果，并利用研究现场作为BDA的示范点。（通过蒸散），和含水层（通过潜流交换和地下水位动态）与BDA实施在流域尺度。为了实现这一目标，将每年在研究地点收集实地和现场观测以及通过无人机（UAV）获得的高分辨率图像，并结合河流-含水层-大气响应的综合建模来约束项目期间及以后的行为。 观测和数值模拟将被用来确定BDA和蒸散量，径流量和地下水位之间的相互作用的水文机制，以充分了解BDA结构如何塑造河流到达的物理水文。实证分析和模型为基础的方法，在这项研究中将直接评估的反应，研究网站的BDA安装。此外，无论是经验和基于模型的分析将产生可转移的洞察力，对水文过程的影响，以及如何与参考河段。由于评估BDA机制和影响的文献几乎不存在，这项工作将为美国西部流域提供急需的背景，因为气候和人类的变化正在发生碰撞。最后，这项工作将通过为更广泛的科学界提供使用无人机进行环境数据收集的模板，大大推进通过无人机进行水文和生态科学数据收集的领域。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In the arid western US, groundwater-surface water interactions have been historically shaped by the presence of beavers, with beaver dams storing and redirecting water into the floodplain. As populations of beavers have declined, local municipalities, state agencies, and private landowners have been installing beaver dam analogues (BDAs), a stream restoration structure that mimics the form of natural beaver dams, in beaver-less stream reaches. Due to their simplicity and expected benefits, BDAs are gaining extensive attention and implementation across the western US, in spite of the absence of clear scientific data to assess their impacts on reach scale hydrology. The proposed project aims to address this gap in knowledge in order to determine the extent to which BDAs alter groundwater and surface water levels, groundwater- surface water exchange, and evapotranspiration by monitoring a research site containing several BDAs located in Wyoming, USA. The project will be performed in close collaboration with The Nature Conservancy of Wyoming (TNC-WY), who owns and manages the research site. While the proposed work aims to improve understanding of hydrological processes in the context of BDA deployment, observations will also inform several management goals associated with BDAs (including reducing stream velocity, reconnecting the stream channel to the floodplain, and supporting riparian vegetation for wildlife habitat and forage for cattle). Investigators will work in close collaboration with TNC-WY to evaluate these management goals, to share findings with local and regional practitioners and stakeholders, and to leverage the research site as a demonstration site for BDAs.The primary objective of this project is to disentangle the complex feedbacks between the stream, atmosphere (via evapotranspiration), and aquifer (via hyporheic exchange and water table dynamics) associated with BDA implementation at the watershed scale. To address this objective, field and in situ observations as well as high resolution imagery via unoccupied aerial vehicle (UAV) will be collected annually at research sites and used in combination with integrated modeling of stream-aquifer-atmosphere responses to constrain behavior during the length of the project and beyond. Observations and numerical modeling will be leveraged to determine the hydrological mechanisms governing interactions between BDAs and evapotranspiration, streamflow, and groundwater levels to achieve a full understanding of how BDA structures shape the physical hydrology of stream reaches. Empirical analyses and model-based approaches employed in this study will directly assess the responses of the research site to BDA installation. In addition, both empirical and model-based analysis will yield transferrable insight regarding the impacts of BDAs on hydrological processes and how this compares with reference reaches. As the body of literature assessing the mechanisms and impacts of BDAs is virtually nonexistent, this work will provide much-needed context for western US watersheds where changes due to climate and humans are colliding. Finally, this work will significantly advance the field of data collection via UAV for hydrological and ecological sciences by providing the broader scientific community with a template to use UAVs for environmental data collection.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.