Spatiotemporal Dynamics of Bedload Sediment Flux in Large Rivers

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NATIONAL SCIENCE FOUNDATIONGEOGRAPHY SPATIAL SCIENCES (GSS) PROGRAMABSTRACTThis research project will provide new knowledge regarding global-scale predictions and analysis of sediment fluxes in large rivers, with special attention given to sediment transported in riverbeds. The investigator will develop a globally distributed, bedload-flux computer model to analyze the spatial interactions between bedload and environmental dynamics as well as the ratio between bedload and sediment transported in suspension. The project will provide new insights into the drivers and mechanisms of fluvial geomorphology, thereby transforming fundamental analytical capabilities with regard to these key geomorphological processes. The project will incorporate a multifaceted educational plan that promotes research, teaching, and participation of students in geography and the geosciences through a combination of research, mentoring, and outreach activities involving graduate, undergraduate, and middle school students as well as the general public. Project results will enhance public awareness of water resources and education through a long-term interpretive exhibit at the Alabama Museum of Natural History. Bedload sediment transport is a significant driver of the physical, biological, and chemical dynamics in river systems, and it affects water quality and availability in river systems, river shape and ecological functioning, and coastal dynamics. The investigator will develop a new bedload flux module within an existing global-scale hydrological modeling framework. The analyses will focus on the universal applicability of the physically based bedload module for large-scale simulations and on the spatial trends of the ratio between suspended and bedload fluxes along river systems as well as its relationship to river basin characteristics. To facilitate these analyses and to validate the model, a globally distributed observational database will be collected from existing U.S. Geological Survey databases, scholarly literature, online resources, and the investigator's collaborative network. Outcomes from this research will provide one of the first spatially and temporally explicit first-order estimates of global bedload flux and a numerical framework for studying the parameters, drivers, and mechanisms of bedload flux in large global rivers. The quantification of sediment transport in rivers will be catalytic for examining carbon and nutrient cycles, river, coastal and marine ecology, dam sustainability, and water and food security.