Pollutant Transport and Mixing Zone Simulation of Sediment Density Currents |
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Authors: | R. L. Doneker J. D. Nash G. H. Jirka |
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Affiliation: | 1Assistant Research Professor, Portland State Univ., Dept. of Civil and Environmental Engineering, PO Box 751, Portland, OR 97207. 2Assistant Professor, Physical Oceanography, College of Oceanic and Atmospheric Sciences, 104 Oceanic Administration Building, Oregon State Univ., Corvallis, OR 97331. 3Professor and Director, Institute for Hydromechanics, Univ. of Karlsruhe, Karlsruhe, D-76131, Germany.
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Abstract: | Prediction of water column concentrations of suspended sediment is often necessary for environmental impact assessment of point source industrial discharges. For example, in “flow lane” or “open water” disposal, suction dredges discharge large volumes of suspended sediment into shallow water disposal locations. A sediment density current mixing model is presented here as part of the D-CORMIX expert system for hydrodynamic simulation of mixing zone behavior. This density current model extends the CORMIX decision support system to simulate continuous negatively buoyant discharges with or without suspended sediment loads on a sloping bottom with loss of suspended particles by sedimentation. Sedimentation is modeled using Stokes settling for five particle size classes. Density current width and depth, trajectory, total solids, tracer concentration, dilution, and particle size concentration are predicted. In addition, location and widths of sediment deposits, accretion rates, including particle size fractions within the spoils deposit, are predicted. The model results are in good overall agreement with available field and laboratory data. |
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Keywords: | Pollutants Density currents Water pollution Environmental quality regulations Waste disposal Dredge spoils Transport phenomena |
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