The main objective of this research was to create a two dimensional and three dimensional Environmental Fluid Dynamics Code (EFDC) model using Aberdeen Pool of the Tennessee-Tombigbee Waterway for the purpose of determining the differences in their ability to address sediment transport. These objectives were reached in the results with comparisons of water levels, sediment concentrations, shear stress, and bed change. The models produced very similar results for the majority of the sediment transport throughout both models with the overall trend being deposition except in the upper limits of the Tombigbee River. The main differences between the two models are produced from the 2D model being depth averaged and the 3D being able to transport sediment vertically. The results show the 2D model tends to erode less and deposit more whereas the 3D model tends to follow the same pattern except for less deposition with more erosion.

This thesis investigates the utilization of hydrodynamic models as tools for assessing factors impacting water quality in the Ross Barnett Reservoir. The primary focus is development of a hydrodynamic model that provides transport information to subsequent application of a water quality model. Environmental Fluid Dynamics Code (EFDC) is a complex, dynamic, multi-dimensional computer model used to simulate hydrology in water bodies. The secondary focus is on data acquisition and manipulation methods for completing the hydrodynamic modeling. Monitoring was completed to create modern bathymetry of Ross Barnett Reservoir to provide accurate model cell grid representation. Temperature and dissolved oxygen profile monitoring occurred to provide data for model output comparison. The EFDC model successfully predicted lake stratification and subsequent mixing based on changes in observed meteorological conditions.

Sediment has profound effects on water quality. Correspondingly, water quality modeling often needs sediment transport modeling. However, simplified descriptive sediment transport was originally employed for water quality modeling, and the linkage between sediment transport models and water quality models is less developed. Therefore, the main purposes of this study were to develop general methods of coupling sediment transport and water quality models and to improve sediment transport modeling for water quality modeling. Linkage of sediment transport and water quality was discussed and a comprehensive sediment transport literature review was conducted. SEDDEER (Sediment Deposition and Erosion), a stand-alone sediment and contaminant fate and transport model, which simulates one water box and the underlying multiple sediment bed layers, was developed. SEDDEER for Visual Basic for Application (SEDDEER_VBA) was written in VBA. SEDDEER for FORTRAN (SEDDEER_FOR) is the corresponding FORTRAN model. To improve WASP in terms of sediment transport, SEDDEER_FOR was incorporated into the WASP TOXI7 module as the starting point to generate the coupled WASP model (WASP_SEDDEER). Verification and validation of SEDDEER_VBA were conducted prior to model application and incorporation. A comprehensive model test was performed to show that SEDDEER_FOR is computationally identical to SEDDEER_VBA. Simple tests were carried out to verify the fluxes across the sediment-water interface and ensure that the coupling of the WASP water column and SEDDEER bed models is correct. The testing results indicated that these models were verified and/or validated. SEDDEER was used to evaluate the effects of sediment on contaminant transport. WASP_SEDDEER, WASP7.4, and EFDC were applied to Mobile Bay to demonstrate the capabilities of WASP_SEDDEER, and WASP_SEDDEER produced a reasonable and consistent modeling result. The results of the study indicated that SEDDEER can be used for one-box sediment and contaminant fate and transport modeling, and also incorporated into water quality models. In addition, WASP_SEDDEER coupling was implemented correctly and can be applied to the real world. Finally, study results show that sediment affects contaminant fate and transport mostly by external forcing and flow conditions, and contaminant fate and transport varies with different sediment and contaminant characteristics and sediment transport processes.

In the development of the watershed, hydrodynamic, and water quality models for St. Louis Bay in Mississippi, the Better Assessment Science Integrating Point and Nonpoint Sources (BASINS 2.0) - Nonpoint Source Model (NPSM) was selected as the watershed model and the Environmental Fluid Dynamics Code (EFDC) which includes hydrodynamic and water quality models was selected as the Bay model. Watershed model calibration was initially accomplished utilizing historical data collected by the U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (USEPA), Mississippi Department of Environmental Quality (MDEQ), and Gulf Coast Research Laboratory (GCRL). The watershed model simulated nonpoint source flow and pollutant loadings for all sub-watersheds, routed flow and water quality, and accounted for all major point source discharges in the St Louis Bay watershed. The model was executed for the period of time spanning from 1965 through 1999 in order to quantify flow and pollutant loadings under a variety of hydrologic conditions. Time varying output from the watershed model was applied directly to the St. Louis Bay model. The Bay model, in turn, simulated hydrodynamics and water quality, including water depth, velocities, salinity, temperature, and fecal coliforms. Final Bay model calibration was performed utilizing a set of site specific data acquired on St. Louis Bay during the period July 14-18, 1998. Model verification was conducted against another set of field data taken in the Bay, during April 18-27, 1999. Fecal coliform was modeled in each of the 750 segments of a three-dimensional system. Comparisons of the predicted and observed data are made qualitatively by using spatial and temporal comparisons. The response of model prediction calculations is consistent with trends of the observed data ranges. The applicability of the mathematical models is also demonstrated for the development of Total Maximum Daily Load (TMDL) for fecal coliform in the St. Louis Bay. The calibrated/verified model will be used as a planning tool to assess the water quality in the Watershed and the Bay as well as for calculating TMDL and Waste Load Allocation (WLA).

This dissertation addresses hydrodynamics, sediment transport and shoreline erosion within the main pool of Hartwell Lake, a U.S. Army Corps of Engineers reservoir built on the Savannah River, between Anderson, South Carolina, and Hartwell, Georgia, USA. A U.S. Environmental Protection Agency (EPA) Superfund site is located on a tributary of Hartwell Lake because of high concentrations of polychlorinated biphenyls (PCBs) in the lake sediments. PCBs are hydrophobic and typically bond to fine-grained sediments, such as silts and clays. The primary goal of the study was to document, through field measurements, and model, using a 3-D numerical model of flow and sediment transport, the fate of sediments within the main pool of Hartwell Lake. To document forty years of sedimentation within the reservoir, bathymetric survey data were collected in Hartwell Lake during the period, February 10-14, 2003. The bathymetric surveys revealed that deposition was, in places, up to two meters thickness in forty years. During the field campaign, flow velocity measurements were made primarily to provide a check on the magnitude of the velocities predicted by the numerical model used in the study. Shoreline surveys provided data for the modeling procedure for shoreline change. This in turn facilitated specification of the sediment flux into the domain via shoreline erosion. Hartwell Lake is located near the southern terminus of the Appalachian mountain chain in the Piedmont region. Sediments contain high fractions of silt and clay. Hartwell Lake has a shoreline length of 1548 km, and erosion of lake shorelines has been a significant problem for many homeowners. As of September 2002, there were 1123 permitted riprap installations, and 393 permitted retaining walls, for a total of 1516 erosion control structures along the lakeshores (source: USACE Hartwell Office), an indication of the magnitude of the erosion problem. To quantify the erosion rate of the shorelines, an approach that relates erosion rates to wind wave forces was developed. A simplified representation of the shape of beach profiles is employed. Historical shoreline change rates were quantified by comparing available digital aerial photos taken in different years, and the erosion prediction model was calibrated using these computed erosion rates. Sediments derived from shoreline erosion were introduced to the model as an additional source along the model boundary, and the fate of the eroding sediments was investigated via numerical modeling.

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Indiana University-Purdue University Indianapolis (IUPUI) / In this research, Environmental Fluid Dynamic Code (EFDC) and Adaptive- Networkbased Fuzzy Inference System Models (ANFIS) were developed and implemented to determine the spatial-temporal distribution of cyanobacterial metabolites: 2-MIB and geosmin, in Eagle Creek Reservoir, IN. The research is based on the current need for understanding algae dynamics and developing prediction methods for algal taste and odor release events. In this research the methodology for prediction of 2-MIB and geosmin production was explored. The approach incorporated a combination of numerical and heuristic modeling to show its capabilities in prediction of cyanobacteria metabolites. The reservoir’s variable data measured at monitoring stations and consisting of chemical/physical and biological parameters with the addition of calculated mixing conditions within the reservoir were used to train and validate the models. The Adaptive – Network based Fuzzy Inference System performed satisfactorily in predicting the metabolites, in spite of multiple model constraints. The predictions followed the generally observed trends of algal metabolites during the three seasons over three years (2008-2010). The randomly selected data pairs for geosmin for validation achieved coefficient of determination of 0.78, while 2-MIB validation was not accepted due to large differences between two observations and their model prediction. Although, these ANFIS results were accepted, the further application of the ANFIS model coupled with the numerical models to predict spatio-temporal distribution of metabolites showed serious limitations, due to numerical model calibration errors. The EFDC-ANFIS model over-predicted Pseudanabaena spp. biovolumes for selected stations. The predicted value was 18,386,540 mm3/m3, while observed values were 942,478 mm3/m3. The model simulating Planktothrix agardhii gave negative biovolumes, which were assumed to represent zero values observed at the station. The taste and odor metabolite, geosmin, was under-predicted as the predicted v concentration was 3.43 ng/L in comparison to observed value of 11.35 ng/l. The 2-MIB model did not validate during EFDC to ANFIS model evaluation. The proposed approach and developed methodology could be used for future applications if the limitations are appropriately addressed.