SWASH is a non-hydrostatic wave-flow model and is originally designed for wave transformation in coastal waters.
However, with the extension of meteorological and baroclinic forcing and solute transport (since version 2.00),
this model is capable of using for large-scale flow and transport phenomena driven by tidal, wind and buoyancy
forces. In this respect, SWASH is very similar to other traditional hydrodynamic models, such as WAQUA,
Delft3D-FLOW, ADCIRC, ROMS, FVCOM, UNTRIM, SLIM and SUNTANS. They mainly differ in numerics and geometric flexibility.
The need to accurately predict small-scale coastal flows and transport of contaminants encountered in environmental issues is becoming more and more recognized. The aforementioned models, however, are orginally designed to simulate large-scale circulation. The development of these models is often dictated by model limitations, numerical techniques and computer capabilities. For instance, the hydrostatic pressure assumption prohibits the models to appropriately simulate surface waves, internal waves, and small-scale flows around hydraulic structures.
In principle, SWASH has no limitations and can capture flow phenomena with spatial scales from centimeters to kilometers and temporal scales from seconds to hours. Yet, this model can be employed to resolve the dynamics of wave transformation, buoyancy flow and turbulent exchange of momentum, salinity, heat and suspended sediment in shallow seas, coastal waters, surf zone, estuaries, reefs, rivers and lakes.