Master of Science (MS)


Oceanography and Coastal Sciences

Document Type



Many research efforts have been made to the Mississippi coastal restoration, but long-term rheological and sedimentological experiments for sediment erosion, deposition and consolidation in diversion receiving basins are still lacking. Push cores and sediment samples were collected from West Bay, a semi-enclosed bay located on the Mississippi River Delta, and Big Mar pond, a receiving basin of the Caernarvon freshwater diversion from the Mississippi River, Louisiana. A dual-core Gust Erosion Microcosm System was used to measure time-series (0.5, 1, 2, 3, 4, 5, and 6-month after initial settling) erodibility at seven shear stress regimes (0.01-0.60 Pa) using experimental cores prepared with two initial sediment concentrations (60 and 120 kg m-3). A 230-cm tall settling column with nine sampling ports was used to measure the consolidation rates for initial sediment concentrations ranging from fluid mud (10 kg m-3) to dredge effluent (120 kg m-3) in combination with two levels of salinities (1 and 5 PSU). The erodibility of West Bay sediment decreases with increasing time of consolidation. The critical shear stress increases from 0.2 Pa after 2-month of consolidation to 0.45 Pa after 4-month of consolidation. Organic content plays a role on both sediment resuspension and consolidation, particularly for Big Mar sediment. The consolidation rates are inversely and exponentially related to initial sediment concentrations. Sediment in 1 PSU tests generally settles faster than that in 5 PSU tests. A model using a single consolidation rate was improved by adding another exponential coefficient. The improved Sanford (2008) model can better predict the consolidation profile of both rapid early settling and slow self-weight consolidation processes.



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Committee Chair

Xu, Kehui