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Full-Text Articles in Environmental Engineering

Combining Inverse And Transport Modeling To Estimate Bacterial Loading And Transport In A Tidal Embayment, Mac Sisson, Jian Shen, Anne Schlegel Jan 2016

Combining Inverse And Transport Modeling To Estimate Bacterial Loading And Transport In A Tidal Embayment, Mac Sisson, Jian Shen, Anne Schlegel

VIMS Articles

Poquoson River is a tidal coastal embayment located along the Western Shore of the Chesapeake Bay about 4 km south of the York River mouth in the City of Poquoson and in York County, Virginia. Its drainage area has diversified land uses, including high densities of residence, agricultural, salt marsh land uses, as well as a National Wildlife Refuge. This embayment experiences elevated bacterial concentration due to excess bacterial inputs from storm water runoff, nonpoint sources, and wash off from marshes due to tide and wind-induced set-up and set-down. Bacteria can also grow in the marsh and small tributaries. It …


Development Of The Hydrodynamic Model For Long-Term Simulation Of Water Quality Processes Of The Tidal James River, Virginia, Jian Shen, Ya Wang, Mac Sisson Jan 2016

Development Of The Hydrodynamic Model For Long-Term Simulation Of Water Quality Processes Of The Tidal James River, Virginia, Jian Shen, Ya Wang, Mac Sisson

VIMS Articles

Harmful algal blooms (HABs) have frequently occurred in the James River. The State has convened a Scientific Advisory Panel (SAP) to review the James River chlorophyll-a standards. The SAP will conduct a scientific study to review the basis for setting the chlorophyll-a standards. To support the SAP study of chlorophyll-a standards, the State of Virginia has decided to develop a numerical modeling system that is capable of simulating phytoplankton and HABs. The modeling system includes a watershed model, a three-dimensional hydrodynamic model and water quality models. The focus of this study will be on the development and verification of the …


Influence Of Wind Strength And Duration On Relative Hypoxia Reductions By Opposite Wind Directions In An Estuary With An Asymmetric Channel, Ping Wang, Harry V. Wang, Lewis Linker, Kyle Hinson Jan 2016

Influence Of Wind Strength And Duration On Relative Hypoxia Reductions By Opposite Wind Directions In An Estuary With An Asymmetric Channel, Ping Wang, Harry V. Wang, Lewis Linker, Kyle Hinson

VIMS Articles

Computer model experiments are applied to analyze hypoxia reductions for opposing wind directions under various speeds and durations in the north–south oriented, two-layer-circulated Chesapeake estuary. Wind’s role in destratification is the main mechanism in short-term reduction of hypoxia. Hypoxia can also be reduced by wind-enhanced estuarine circulation associated with winds that have down-estuary straining components that promote bottom-returned oxygen-rich seawater intrusion. The up-bay-ward along-channel component of straining by the southerly or easterly wind induces greater destratification than the down-bay-ward straining by the opposite wind direction, i.e., northerly or westerly winds. While under the modulation of the west-skewed asymmetric cross-channel bathymetry …


Modeling Flocculation And Deflocculation Processes Of Cohesive Sediments, Xiaoteng Shen Jan 2016

Modeling Flocculation And Deflocculation Processes Of Cohesive Sediments, Xiaoteng Shen

Dissertations, Theses, and Masters Projects

The transport and fate of cohesive sediments are responsible for many engineering, environmental, economic and policy issues that relate to, for example, siltation and dredging in navigation channels, water quality, water turbidity, pollutant transports, and biological ecosystem responses. Our current understanding, however, is insufficient to conduct accurate quantitative predictions of these processes. This is because the cohesive particles in natural waters will flocculate, which determines the settling, and thus the deposition behaviors. The simulation of flocculation processes is a primary challenge since the time variation of Floc Size Distribution (FSD) is controlled by a partial differential equation that also contains …