Development of a Three Dimensional Dissolved Oxygen Model for the Lower Savannah River Estuary (original) (raw)
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The Savannah Harbor is one of the busiest ports on the East Coast of the United States and is located downstream from the Savannah National Wildlife Refuge, which is one of the Nation's largest freshwater tidal marshes. The Georgia Ports Authority and the U.S. Army Corps of Engineers funded hydrodynamic and ecological studies to evaluate the potential effects of a proposed deepening of Savannah Harbor as part of the Environmental Impact Statement. These studies included a three-dimensional (3D) model of the Savannah River estuary system, which was developed to simulate changes in water levels and salinity in the system in response to geometry changes as a result of the deepening of Savannah Harbor, and a marsh-succession model that predicts plant distribution in the tidal marshes in response to changes in the water-level and salinity conditions in the marsh. Beginning in May 2001, the U.S. Geological Survey entered into cooperative agreements with the Georgia Ports Authority to ...
Calibration of a 3-D Hydrodynamic and Salinity Model of the Savannah River Estuary
2003
In support of an Environmental Impact Statement (EIS) for a proposed harbor expansion project a three-dimensional hydrodynamic model was applied to serve as a tool to determine potential project impacts. The hydrodynamic model simulated salinity, currents, water surface elevation, and volume flows for the entire Lower Savannah River Estuary system (over 60 river miles). The model was calibrated and validated over two 100-day periods in 1999 and 1997, respectively. The model proved to be capable of reproducing complex, transient physical phenomena in this extremely dynamic system and provided good agreement with observed values of surface elevation, currents, and salinity. The model will be used to directly calculate project induced changes to the hydrodynamic and salinity environment, and will also provide the input to several other studies, including: a water quality model, a marsh vegetation model, and a river sedimentation model.
Preliminary Data from a Comprehensive Savannah River Study: The First 6 Months
Southeastern Natural Sciences Academy has initiated a two year comprehensive study to assess the upstream impacts on water quality in the Savannah River with emphasis on the Augusta urban corridor. One of the driving forces of the study is characterization of the upstream contribution of oxygen demanding substances to the Savannah Harbor. The ongoing study began in January 2006 and encompasses the physical, chemical, and biological domains of limnology. We have employed both Eulerian and Lagrangian approaches through continuous collection of data from static multiparameter probe stations and through flow based chemistry sampling events, respectively, with stations spanning from River Mile 148 (near Plant Vogtle) to River Mile 215 (above Augusta, GA). This presentation represents a portion of the first 6 months of collected Eulerian and Lagrangian data. Preliminary Eulerian results showed that, on average, temperature and conductivity increased steadily from river mile 215 to river mile 148 with the highest variability for both parameters at the downstream station. The overall trend for pH showed no net change from River Mile 215 to 148 but pH increased by nearly 1 unit at River Mile 202 and was most variable at that location. The overall trend for dissolved oxygen showed a net loss of ~0.5 mg O 2 /L from River Mile 215 to 148 but increased by an average of 1.5mg O 2 /L at River Mile 202 and remained elevated through River Mile 185. Lagrangian sampling results for the May sampling event showed that increases in conductivity from River Mile 215 to 148 mostly resulted from downstream increases in sodium, alkalinity (as CO 3), sulfate, chloride, potassium, calcium, and iron. Total organic carbon, almost entirely in the dissolved phase, increased from River Mile 215 to 148. This increase was equivalent to ~700 kg C added to the river over that reach, none of which was characterized as a biologically oxygen demanding substance (BOD 5) but may have been characterized as an oxygen demanding substance under harsher conditions (COD).
2007
The Savannah Harbor is one of the busiest ports on the East Coast of the United States and is located downstream from the Savannah National Wildlife Refuge, which is one of the Nation’s largest freshwater tidal marshes. The Georgia Ports Authority and the U.S. Army Corps of Engineers funded hydrodynamic and ecological studies to evaluate the potential effects of a proposed deepening of Savannah Harbor as part of the Environmental Impact Statement. These studies included a three-dimensional (3D) model of the Savannah River estuary system, which was developed to simulate changes in water levels and interstitial (or pore-water) salinity in the system in response to geometry changes as a result of the deepening of Savannah Harbor, and a marsh-succession model that predicts plant distribution in the tidal marshes in response to changes in the water-level and interstitial salinity conditions in the marsh. Beginning in May 2001, the U.S. Geological Survey entered into cooperative agreement...
Development of water quality model in the Satilla River Estuary, Georgia
Ecological Modelling, 2004
A coupled three-dimensional physical and water quality model was developed for the Satilla River Estuary, Georgia. The physical model is a modified ECOM-si version with inclusion of flooding/draining process over the intertidal salt marsh. The water quality model is a modified WASP5 with inclusion of nutrient fluxes from the bottom sediment layer. The coupled model was driven by tidal forcings at the open boundary in the inner shelf of the South Atlantic Bight (SAB) and real-time river discharge at the upstream of the estuary. The initial condition for salinity was specified using the field measurement data taken along the estuary. The water quality components were assumed as constant values everywhere at the initial, with assumption that the spatial and temporal variations of these variables were caused by physical-biological-chemical interactions under strong tidal mixing environment. The model-predicted concentrations of inorganic nutrients (ammonium, nitrate plus nitrite, and ortho-phosphorus), chlorophyll-a, and dissolved oxygen (DO) in an along-estuary transect were in reasonable agreement with observational data. Process studies suggest that the intertidal salt marsh acts as a main sink for particulate materials and a major consumer of DO. The low DO concentration in the Satilla River Estuary was mainly due to high sediment oxygen demand (SOD) over the intertidal salt marsh. This feature is the nature of the estuarine-salt marsh ecosystem with nothing related to anthropogenic activities. Tidal mixing-induced bottom resuspension process played a critical role in supplying the nutrients in the water column in addition to the nitrification process.
2000
Ecologists are studying the response of tidal wetlands of the Savannah Harbor watershed (Figure1) as part of the potential deepening of the Savannah Harbor. The information derived will be used to help interpret results of marsh studies, particularly the marsh hydrology studies that are to be used in conjunction with the hydrodynamic modeling to extrapolate project impacts spatially across the marsh-floodplain surface. These data will be converted into a "marsh succession model" that will be used with inputs from a three dimensional (3D) hydrodynamic model to predict the overall impact of the harbor deepening on the area's ecosystem. The linkage between the water level and specific conductance of the tidal marshes to the Savannah River is critical to developing a successful marsh succession model.
Estimating salinity intrusion effects due to climate change on the Lower Savannah River Estuary
2010
The ability of water-resource managers to adapt to future climatic change is especially challenging in coastal regions of the world. The East Coast of the United States falls into this category given the high number of people living along the Atlantic seaboard and the added strain on resources as populations continue to increase, particularly in the Southeast. Increased temperatures, changes in regional precipitation regimes, and potential increased sea level may have a great impact on existing hydrological systems in the region. Important freshwater resources are located proximal to the freshwater-saltwater interface of the estuary. The Savannah National Wildlife Refuge is located in the upper portion of the Savannah River Estuary. The tidal freshwater marsh is an essential part of the 28,000-acre refuge and is home to a diverse variety of wildlife and plant communities. Two municipal freshwater intakes are located upstream from the refuge. To evaluate the impact of climate change on salinity intrusion on these resources, inputs of streamflows and mean tidal water levels were modified to incorporate estimated changes in precipitation patterns and sea-level rise appropriate for the Southeastern United States. Changes in mean tidal water levels were changed parametrically for various sea-level rise conditions. Preliminary model results at the U.S. Geological Survey (USGS) Interstate-95 streamgage (station 02198840) for a 7½-year simulation show that historical daily salinity concentrations never exceeded 0.5 practical salinity units (psu). A 1-foot sea-level rise (ft, 30.5 centimeters [cm]) would increase the number of days of salinity concentrations greater than 0.5 psu to 47 days. A 2-ft (61 cm) sea-level rise would increase the number of days to 248.
2003
began ecological baseline studies on the Savannah River Site with financial support from the Atomic Energy Commission. Throughout its history, SREL has been operated by The University of Georgia. Mission The Savannah River Ecology Laboratory's mission, as defined in its Cooperative Agreement with the U.S. Department of Energy (DOE), is to provide an independent evaluation of the ecological effects of Savannah River Site (SRS) operations through a program of ecological research, education, and outreach. This program involves basic and applied environmental research, with emphasis upon expanding the understanding of ecological processes and principles, and upon evaluating the impacts of industrial and land use activities on the environment. This mission is accomplished through a broad-based program of field and laboratory research conducted on the SRS and published in the peer-reviewed scientific literature; by providing education and research training for undergraduate and graduate students from colleges and universities throughout the United States and abroad; and by engaging in community outreach activities and service to professional organizations.
2002
began ecological baseline studies on the Savannah River Site with financial support from the Atomic Energy Commission. Throughout its history, SREL has been operated by The University of Georgia. Mission The Savannah River Ecology Laboratory's mission, as defined in its Cooperative Agreement with the U.S. Department of Energy (DOE), is to provide an independent evaluation of the ecological effects of Savannah River Site (SRS) operations through a program of ecological research, education, and outreach. This program involves basic and applied environmental research, with emphasis upon expanding the understanding of ecological processes and principles, and upon evaluating the impacts of industrial and land use activities on the environment. This mission is accomplished through a broad-based program of field and laboratory research conducted on the SRS and published in the peer-reviewed scientific literature; by providing education and research training for undergraduate and graduate students from colleges and universities throughout the United States and abroad; and by engaging in community outreach activities and service to professional organizations.