Abstract: During 1998~2000, the CADAM (Concerted Action on Dambreak Modelling) project had been set in motion by the European Union to investigate current methods and their use for simulation and prediction of the effects of dam failures. Addressing issues originally identified by the CADAM project, the IMPACT (Investigation of ExtreMe Flood Processes And UnCertainTy) project addressed the assessment and reduction of risks from extreme flooding. The paper introduced the main conclusions of CADAM as well as the IMPACT project.