Portland State University. Department of Civil Engineering
Term of Graduation
Date of Publication
Master of Science in Civil Engineering (MSCE)
Contaminated sediments -- Oregon -- Portland, Columbia River Slough (Portland, Or.)
1 online resource (xi, 210 pages)
An integrated modeling system has been developed to simulate sediment and contaminated sediment transport in the Upper Columbia Slough System during the Flood of 1996. The modeling system consists of a hydrodynamic model, a sediment transport model, and a contaminant transport model. The hydrodynamic model predicts the Slough flow dynamics and sediment transporting power; the sediment transport model predicts flow-induced sediment transport; and the contaminant transport model predicts the migration of contaminated sediments in the Slough system.
The Upper Columbia Slough modeling system is characterized by its recognition of the complex interplay of Slough hydrology, hydrodynamics, sediment transport, contaminant transport. The modeling system is also characterized by its ability to simulate both cohesive and noncohesive sediments and the associated contaminant transport.
The hydrodynamic model was calibrated using water level obtained over a twomonth dry period in 1993. The sediment transport model was not calibrated. The sediment model utilized the typical values from extensive literature review and from the calibration results of the Lower Columbia Slough sediment transport model to specify the parameters governing deposition and resuspension processes.
The model results indicate that the hydraulic power in Upper Slough is weak under normal conditions, and existing sediment in the Slough moves very little unless there is a major stonn. Winter large storm events dominate Upper Slough dynamics and dictates sediment transport. The model predicted significant sediment resuspension but minimal bedload transport further downstream from the Mid-Dike and upstream of MCDD#4 on the Slough main channel during the 1996 flood. The model predicted little or no sediment transport throughout the southern arm system The study also concluded that none of the contaminated sediment priority sites would have significant sediment transport during the major storm events.
The study points out that future model improvement should be focused on calibrating the key model parameters that determine sedimentation rates, such as critical shear stress for erosion and deposition.
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Wu, Binghong, "Numerical Simulation of Contaminated Sediment Transport in the Upper Columbia Slough System" (1997). Dissertations and Theses. Paper 6283.