Recent extreme flood events in the center of Europe caused public discussion on the question whether more frequent and more severe floods are getting and conditions for flooding getting more severe are at least partially man-made. This paper presents a research project, in which the impact of the land use changes on flood hydrographs is investigated. After a presentation of a distributed rainfall-runoff model, which parameters are determined on the basis of satellite imagery, digital terrain models and digital maps, the validity of the model is demonstrated for a subcatchment within the international Mosel river basin. Two types of land use are investigated: the increased urbanization and forest disease leading to large scale forest death. Scenarios are developed for the test catchment: a) the urbanized area is considerably increased and b) all trees above 400 m asl are assumed to be dead. It is shown how such land use changes can be generated on maps and how the parameters of the hydrological model change according to those land use changes. For a selected historical flood the impact of the changes on the flood hydrograph are presented: in both cases a) and b) flood conditions became more severe, i.e. the rising limb becomes more steep, the peak considerably higher and the flood volume significantly larger. Both investigated types of land use changes produce a significant deterioration of flood conditions.