The computational domain covers the entire Satilla River Estuary including main channels of the river, tidal creeks, and intertidal salt marshes. The model is discretized using non-overlapped triangular cells with a horizontal resolution of 40 to 100 m in the main channel of the river and the intertidal salt marshes, and up to 2500 m near the open boundary in the inner shelf (see Figure enclosed below) Eleven sigma-levels are used in the vertical, which allows for a smooth representation of finite-amplitude irregular bottom topography and real estuarine geometry. These levels correspond to a vertical resolution of 1.5 at a depth of 15 m outside of the estuary and 0.2 cm or less in the shallow region of the estuary.

The unstructured grid is built using the MSM 8.0 commercial software. In the figure of the grids, the water zone is colored with grey and intertidal salt marsh zone is distinguished wwith dark brown. The connection to other rivers are cut at the branch region and open boundaries are then specified at the cuting line. The outer edge of the grid over the shelf is the open boundary, at which tidal forcing is specified. River discharge is added into the computational domain at the upstream end of the river.

Two amplified grid figures posted in the up- and down-left corners are selected near the mouth of the river and upstream river branches. They provide examples of unstructured grids in the estuarine-tidal creek-intertidal salt marsh complex and also in the upstream narrow river branches. A more detailed figure of the model grid is available at MEDM laboratory at UMASS.