Collaborative Research: Dynamic connectivity of river networks as a framework for identifying controls on flux propagation and assessing landscape vulnerability to change

河网通过促进水、沉积物和营养物质等环境通量的运输和分布，在塑造景观方面发挥着关键作用。这些网络不仅为淡水物种提供了栖息地，而且还为可引起严重疾病的水媒病原体提供了通道。研究人员将开发一个预测框架，该框架将提供定量理解河网的拓扑（结构连通性）、几何（河道长度、坡度等）和突发特征（例如，河道短暂性）如何在稳定和瞬态条件下影响通量运动的动态。这一框架将有可能评估不同的变化情景，如气候和土地利用变化，如何影响未来河网在整个景观中运输水文、生态和生物地球化学通量的能力。该框架还可以为管理河网的决策提供信息，以减少其洪水的可能性和频率，以及流域内关键地点的病原体浓度。该项目将传播有关河流网络及其运输模式和性质的基础知识和应用知识，重点是它们与水文学、工程和地球科学的相关性，面向K-12、本科生和研究生的不同受众。拟议的研究采用整体（数学-物理-观测）方法，通过在单一框架内整合静态，动态和紧急连通性属性来理解河网的通量动力学，从而提供了评估不同变化情景（如气候和土地利用变化）如何影响未来河网在整个景观中运输水文，生态和生物地球化学通量的能力的潜力。它利用网络理论、遥感和野外观测、水文学原理和数值模拟的优势来破译控制河网通量传输动态模式的关键拓扑、几何和紧急控制。特别是，研究人员的目标是(i)揭示河流网络在运输过程中对通量聚集施加的最相关控制，（ii）量化它们与气候和人类活动等外部强迫的关系，以及（iii）提出识别变化热点的脆弱性指标。该奖项反映了美国国家科学基金会的法定使命，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。

River networks play a critical role in shaping landscapes by facilitating the transport and distribution of environmental fluxes such as water, sediment, and nutrients. These networks not only provide habitats for freshwater species but also serve as conduits for water-borne pathogens that can cause severe diseases. Researchers will develop a predictive framework that will provide quantitative understanding of how the topological (structural connectivity), geometric (channel length, slope, etc.), and emergent features (e.g., channel ephemerality) of river networks influence the dynamics of flux movement under both steady and transient conditions. This framework will have the potential to assess how different scenarios of change, such as climate and land use change, may affect the future of river networks in their capacity to transport hydrological, ecological, and biogeochemical fluxes throughout the landscape. This framework can also inform decisions about managing river networks to reduce their flooding potential and frequency, as well as the concentration of pathogens at critical locations within a basin. The project will disseminate fundamental and applied knowledge about river networks and their transport patterns and properties, with a focus on their relevance to hydrologic, engineering and earth sciences, to a diverse audience of K-12, undergraduate, and graduate students. The proposed research takes a holistic (mathematical-physical-observational) approach to understanding the flux dynamics on river networks by integrating static, dynamic and emergent connectivity attributes within a single framework that offers the potential to assess how different scenarios of change, such as climate and land use change, may affect the future of river networks in their capacity to transport hydrological, ecological, and biogeochemical fluxes throughout the landscape. It leverages the strengths of network theory, remote sensing and field observations, hydrologic principles and numerical modeling to decipher the key topological, geometric, and emergent controls that govern dynamic patterns of flux transport on river networks. In particular, the researchers aim to (i) unveil the most relevant controls imposed by river networks on the aggregation of fluxes during the transport process, (ii) quantify their relation with external forcing such as climate and human actions, and (iii) propose vulnerability indicators for identifying hot spots of change.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.