Summary:

In the frame of a country-scale project "IT system for protection against extraordinary hazards" (ISOK), tasks aiming at the development of flood risk maps are realized. The major activity related is the creation of hydrodynamic models (1D) for rivers with significant flooding potential. For certain conditions, especially for urban areas a 2D modelling is recommended and will also be applied. The paper presents the current methodological background and the feasibility of numerical hydraulic modelling. Data resources and their processing along with software for numerical computation and results visualisation will be outlined. A focus will be given to the geoinformation data, in particular to air-born Digital Elevation Models (DEM) and 2D hydrodynamic modelling tools. Finally, a 2D hydrodynamic model for the Nysa Łużycka simulating the passage of flood in 2010, influenced by the failure of the Niedów Dam, will be presented as well.