Event

Fine particle dynamics in rivers:  Transport, retention, and morphodynamics: Suspended particle transport typically represents a substantial fraction of the total sediment flux in rivers.  Because fine particle concentrations are often similar along the length of rivers, there has been a tendency to think that they have simple dynamics, and fine suspended particles have historically been considered to show little interaction with streambed sediments.  This is a fallacy.  A wide range of processes cause exchange of water and suspended matter between rivers and underlying groundwater.  Recent observations have demonstrated that fine particles show complex dynamics in rivers, including continuous deposition and resuspension in streambed sediments. This provides substantial opportunity for interaction of stream-borne material with underlying sediments, and this interaction is expected to alter the hydrogeological properties of fluvial deposits and increase the opportunity for metabolism of terrestrial particulate organic matter in rivers.  In this presentation, I will briefly review current understanding of surface-groundwater exchange processes, develop a conceptual model for fine particle deposition and resuspension in rivers, and present a stochastic modeling framework for these processes.  I will close by discussing the limits of current understanding and prospects for future development of more general models for coupled hydrologic and geomorphic processes in river systems.

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