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

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 an 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.