EIA 3d model is a three-dimensional numerical finite difference hydrodynamic model, than can be used to model surface waters such as lakes, rivers, floodplains and coastal areas. It is baroclinit, e.g. takes into account water density variations caused by temperature and salinity differences. The model uses dynamically coupled rectangular nested grids, which means that the model can have very dense and accurate resolution near the target area, when in the same time also taking into account the effect of large water areas surrounding the point of interest. Specific applications include computation of sediment transport, flooding, cooling water spreading and transport of nutriets and harmful substrances. Recent applications location have been Baltic sea coastal locations, parts of Baltic Sea (e.g Gulf of Finland), Lake Tonle Sap and Mekong Floodplains in South-East asia, and inland lakes in Baltic area.