Continuous Hydrodynamic and Water Quality Data Collection in Support of a Three-Dimensional Model Calibration and Dissolved Oxygen TMDL Application for the Lower Savannah River Estuary
Two continuous hydrodynamic and water quality data collection efforts were performed on the Lower Savannah River Estuary during the summers of 1997 and 1999 to support a threedimensional model calibration. Field studies in the estuary were conducted over two separate, three-month periods
in the summers of 1997 and 1999, respectively. The three dimensional modeling study of the Lower Savannah River Estuary is being conducted to support decision making in an Environmental Impact Statement (EIS) for the Georgia Ports Authority's (GPA) Savannah Harbor Expansion Project (SHEP).
1999 Data Collection Effort was designed to be more comprehensive than the 1997 Data Collection Effort after stakeholder comments were received on the Tier I EIS model prediction and applications. Predictions and applications presented in the Tier I EIS were based on the model calibration
to the 1997 Data Set. In order to address the specific stakeholder comments from the Tier I EIS, the Stakeholder Evaluation Group (SEG) was created. The SEG recommended various studies to address potential impacts of the SHEP identified by the Tier I EIS modeling study.
The Modeling Technical
Review Group (MTRG), a subcommittee of the SEG, worked with Applied Technology and Management (ATM) to develop the scope of the 1999 Data Collection Effort. The MTRG is comprised of leading modeling experts from USACE, EPA, USGS, Georgia Environmental Protection Division and South Carolina
Department of Health and Environmental Control and Skidaway Institute of Oceanography. The specific goals and procedures for the 1999 Data Collection effort developed with the MTRG were outlined in Task Statements.
The Task Statements for the 1999 Data Collection Effort were designed to
support the calibration of a three-dimensional water quality model capable of evaluating all potential adverse impacts identified in the Tier I EIS modeling study. The study area has been modified extensively from a natural condition since the early 1800's including the construction of
a tide gate in one of the channels, earlier channel deepening projects and opening and closing various passages between the Front, Middle and Back Rivers. Earlier studies on the previous modifications have shown that dramatic variations in the temporal and spatial distribution of salinity
can result from these modifications. The Tier I EIS modeling study demonstrated the significant influence of vertical stratification in the river channel on the water quality characteristics of the Lower Savannah River.
The 1999 Data Collection Effort was designed to capture the three-dimensional
hydrodynamic and water quality characteristics, which ultimately affect dissolved oxygen concentrations in the Lower Savannah River Estuary. Therefore, point source discharges in the study area and nonpoint sources were accounted for in the water quality model. After being used to evaluate
the effects of Harbor modifications, the water quality model will be used in support of TMDL development and ecosystem restoration projects.
The paper and presentation will provide an in-depth discussion of the 1999 Data Collection Effort for the Lower Savannah River, one of the most comprehensive
data collection efforts ever undertaken for the calibration of a three-dimensional water quality model. It will highlight the unique challenges faced, including coordination with stakeholders, manpower requirements, instrumentation, analytical laboratories, tidal and seasonal conditions, and
the weather. It will also provide information on several innovative practices for instrumentation servicing and deployment. The experiences and descriptions provided in this paper will provide insights into the complexities of continuous monitoring for future comprehensive data collection
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