2D model with changing land-water boundaries

A so-called ″2.5D″ model is used to simulate the flow field in the vertical plane. The model solves the momentum equations in a vertical plane by only taking into account the derivatives in the longitudinal direction, the variables are considered to be uniform in the other horizontal direction. Three different test cases have been set up. The first one is a rectangular, shallow basin with constant bathymetry and driven by a constant wind. The next case consist of a shallow basin with inside a deep channel and the third one is a basin with an island situated in the center, which is partly drying out during low water. The last case has been set up to test the capability of the FADI model for simulating tidal flats. The flow fields in the vertical plane for the last two cases have been simulated by the 2.5D model using the surface gradients calculated by the FADI model.