Fine Particle Migration and Solute Fluxes in Sediment Beds: Analysis of Sediment Structural Dynamics Using 3D Micro-Tomography

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0310657Packman The proposed work will advance our understanding of sedimentary processes by combining detailed observations of bulk sediment transport with fine-scale measurements of the resulting three-dimensional sedimentary structure. These processes will be studied in a recirculating flume in order to provide control of flow conditions and to allow direct observation of sediment transport processes. The Advanced Photon Source at Argonne National Lab will be used to perform 3D X-ray micro-tomography and X-ray fluorescence mapping on intact sediment cores taken from the flumes. The primary goals of these observations will be to examine the evolution of bulk sediment structure, specifically the development of heterogeneous depositional structures. Sediment mixing will also be determined from observations of the redistribution of tracer particles that will be specifically synthesized to provide good contrast for X-ray tomography. A conservative solute will be used to assess pore water fluxes resulting from stream-subsurface flow coupling. Fundamental models will be applied to assess the migration of fine particles within the sediment bed and the resulting development of heterogeneous sedimentary conditions. This study will provide key understanding of the linkage between hydrologic processes and sediment structure. Graduate and undergraduate students involved in this project will gain experience with detailed, process-oriented, interdisciplinary environmental studies. In addition, active international collaboration and student exchange programs will encourage project participants to engage in global scientific endeavors. Finally, involvement of K-12 teachers and use of project laboratory facilities for educational tours and demonstrations will disseminate project results to pre-college students and encourage them to pursue similar studies.