Numerical Modeling of Hydrodynamic Circulation and Cohesive Sediment Transport in Hartwell Lake, South Carolina/Georgia, USA

This paper describes numerical modeling of hydrodynamic circulation and cohesive sediment transport in Hartwell Lake, South Carolina/Georgia, a U.S. Army Corps of Engineers (USACE) hydropower and flood control reservoir. A U.S. Environmental Protection Agency (EPA) “Superfund” site is located on a tributary to the lake because of high concentrations of polychlorinated biphenyls (PCBs) in the lake sediments. The primary objective of this study involves prediction of depositional zones for sediments transported within the reservoir.

The EFDC (Environmental Fluid Dynamics Code) model developed by Hamrick (1996) is used to describe lake hydrodynamics and sediment fate. Historical records of wind and flow were used to determine frequencies of occurrence and representative conditions for prediction of long-term deposition zones for sediment transported by the flow.

Sensitivity of hydrodynamic processes to model parameters were investigated and wind was found to be the major force driving the circulation. Model results for cases with realistic long-term forcing indicated likely zones of sediment deposition, useful for mitigation of pollution problems as well as predictions of reservoir lifetime and development of maintenance schemes.