Collaborative research: Linking scales of geomorphology and solute transport in river corridors

PI：Aaron Packman（西北大学），道格拉斯Jerolmack（宾夕法尼亚大学），JudHarvey（美国地质调查局）概述：河流中的溶质运移是一个受水文和地貌动力学影响的复杂问题。重要的是要能够预测水文动力学，地貌动力学和溶质运移的相互作用，以提高长期平均河流系统的地球化学处理率的评估。河流-地下水文相互作用受地表形态的调制，并强烈影响河流和孔隙沃茨中的溶质运移，从而控制了非常广泛的地球化学过程。在这里，我们建议获得一个独特的新的数据集，包括在一个砂床河流的河流形态动力学和溶质运移的观测频繁的高流量和泥沙输运事件。我们还建议开发新的理论，使以前观察到的地貌和地表-地下水相互作用的比例关系纳入长期平均溶质在河流中的传输模型。该模型将通过纳入观测到的水流变化和河道形态的统计数据而应用于研究现场，并将通过直接观测溶质渗透到地下和在一系列时间尺度上平均的净下游溶质输运来进行测试。这项工作的智力价值在于推进对河流水文学，河流形态动力学，地表-地下水相互作用和河流中的溶质运移。这是一个非常复杂的问题，因为它不仅涉及湍流边界的相互作用，但也泥沙输运和孔隙流体流动的高度不均匀的近流环境。在这里，我们将综合许多最近的观察和假设，分别在水文和地貌，以确定如何在河流中的流动动力学和形态动力学之间的联系控制溶质运移在不同的空间和时间尺度。虽然现在人们普遍认识到，为了以综合的方式评估环境系统的行为，需要进行这种综合，但这种综合在实践中很少实现。通过开发新的理论，利用地貌和水文尺度关系的共性，我们使明确的综合过程，控制溶质运移动力学在各种空间和时间尺度上的河流corridors.Broader影响：拟议的努力将有助于非常广泛的环境科学和相关的水资源和水生生态系统的管理。此外，通过各种协同活动，我们还将在人力资源开发和整个科学界产生许多更广泛的影响。该项目的结果将提供重要的，必要的能力，以评估各种重要的溶质在河流系统中的迁移。迫切需要可用于预测形态学变化的联系的工具（例如，土地利用变化）和可变水文强迫（自然水流变率和替代气候变化情景）下的长期平均迁移行为。因此，预计项目结果不仅有助于详细了解河流动力学，而且在支持分析河流系统中碳、营养物、污染物和一系列其他重要物质的迁移和处理方面具有非常广泛的影响。从根本上说，该项目的努力为实现以科学为基础的淡水资源可持续管理迈出了关键的一步。我们将通过支持更广泛的科学界研究这些问题，进一步加强这些一般性贡献。我们将存档我们将获得的独特的现场数据集，并将其公开提供给其他理论家和建模人员，以促进河流走廊流量和运输模型的更广泛开发和测试。我们还将通过在主要技术会议上召开多个定向跨学科会议，并将项目结果直接转化为NSF目前赞助的更广泛的水文综合活动，促进科学讨论，特别是科学成果的综合，以解决政策和管理问题。最后，我们将通过这项工作培训许多年轻的研究人员，通过参与协同和合作的国际活动，并通过利用项目成果进一步推动我们正在进行的努力，鼓励大学预科学生，特别是来自代表性不足的少数民族的学生，进入科学事业，

PIs: Aaron Packman (Northwestern University), Douglas Jerolmack (University of Pennsylvania), Jud Harvey (U.S. Geological Survey)Overview: Solute transport in rivers is a complex problem influenced by both hydrologic and geomorphic dynamics. It is important to be able to predict the interactions of hydrologic dynamics, geomorphic dynamics, and solute transport in order to improve assessment of long-term average biogeochemical processing rates in river systems. Stream-subsurface hydrologic interactions are modulated by surface morphology and strongly affect solute transport in both streams and pore waters, thereby controlling a very wide range of biogeochemical processes. Here we propose to obtain a unique new data set encompassing observations of both fluvial morphodynamics and solute transport in a sand-bed river subject to frequent high-flow and sediment-transport events. We also propose to develop new theory to allow scaling relationships previously observed in both geomorphology and surface-groundwater interactions to be incorporated into a model for long-term average solute transport in rivers. The model will be applied to the study site by incorporating observed statistics of stream flow variations and channel morphology, and will be tested using direct observations of both solute penetration into the subsurface and net downstream solute transport averaged over a range of time scales.Intellectual Merit: The intellectual merit of this work lies in advancing fundamental understanding of the linkage between stream hydrology, fluvial morphodynamics, surface-groundwater interactions, and solute transport in rivers. This is an exceedingly complex problem as it involves not only turbulent flow-boundary interactions, but also sediment transport and pore fluid flow in the highly heterogeneous near-stream environment. Here we will synthesize numerous recent observations and hypotheses developed separately in hydrology and geomorphology in order to ascertain how the linkage between flow dynamics and morphodynamics in rivers controls solute transport over various spatial and temporal scales. While it is now generally recognized that such synthesis needs to be done in order to assess the behavior of environmental systems in an integrated fashion, such integration has rarely been achieved in practice. By developing new theory that takes advantage of commonality in geomorphic and hydrologic scaling relationships, we enable explicit evaluation of the integrated process that control solute transport dynamics over a variety of spatial and temporal scales in river corridors.Broader Impacts: The proposed effort will contribute very broadly to environmental science and the associated management of water resources and aquatic ecosystems. Further, through a variety of synergistic activities we will also realize numerous broader impacts in human resource development and in the scientific community at large. The project results will provide significant, necessary capability to evaluate the migration of a wide range of important solutes in river systems. There is a critical need for tools that can be used to predict the linkage of morphological variations (e.g., land-use changes) and long-term average transport behavior under variable hydrologic forcing (natural flow variability and alternative climate change scenarios). Therefore the project results can be expected to not only contribute detailed understanding of river dynamics, but also to have very broad impacts in supporting analysis of the migration and processing of carbon, nutrients, contaminants, and a range of other important substances in river systems. Essentially, the project efforts provide a critical step towards scientifically based sustainable management of freshwater resources. We will further enhance these general contributions by supporting the broader scientific community working on these problems. We will archive the unique field data set that we will acquire, and make it publicly available to other theoreticians and modelers to facilitate broader development and testing of models for flow and transport in river corridors. We will also facilitate scientific discourse, and particularly synthesis of scientific results to address policy and management questions, by convening multiple, directed interdisciplinary sessions at major technical conferences, and by translating project results directly into the broader Hydrologic Synthesis activity currently sponsored by NSF. Finally, we will realize broad contributions to human resource development by training numerous young investigators through this work, by engaging in synergistic and collaborative international activity, and by using project results to further our ongoing efforts to encourage pre-college students, and particularly students from under-represented minorities, to enter careers in science