Modeling Hydrodynamics and Storm Effect in the Altamaha River Sound

The Altamaha River has the largest watershed among Georgia's rivers and the second largest one among the eastern United States. Despite its importance, die Altamaha River sound and its hydrodynamics are not studied extensively. This study is composed of two parts. In the first part we investigated hydrodynamics in the Altamaha River sound using a numerical model in order to understand the basic behavior of contaminant transport in this region. This numerical study is carried out using EFDC (Environmental Fluid Dynamics Code), which is a widely used 3-D hydrodynamics and transport model. To simulate a realistic case, various data such as history of wind and river discharge is obtained and applied. Result shows that the tides are the major forcing factor in contaminant transport in the sound. A three-dimensional structure of salinity, a salt wedge, is also observed to influence the transport process. The second part of this study deals with impacts of possible hurricanes in the region. A hypothetical long wave as a storm surge is assumed and its effects are simulated using the same techniques and tools used in the first part. No significant delay of wave is observed. The transport of contaminants released by this flooding is studied as well with drifting particles in the simulations. The movement of particles depends on where they are initially released and geographical configuration of the release point. Some particles settle on ground and others stay in bays several days before they are discharged into the ocean.