Paper presents the analysis of consequences of hypothetical breach of Przeczyce storage reservoir earth dam, located on Czarna Przemsza river (Silesia). The studies were divided on two essential parts. In the first one the process of dam body wash-out applying computer program Dam-Breach has been analysed, assuming dam crest overflow as probable cause of failure. Time duration of dam body washing out, breach parameters and outflow have been determined. In the second part the conditions of hypothetical flood wave routing along the river Czarna Przemsza valley have been analysed applying computer program Dam-Break. Velocity and flood wave passage time have been determined. Results of calculations have been plotted on topographic maps, on which the potential threat zones related to time of wave reach to an analysed cross-section have been marked too. On the basis of calculations, for area located along the flood wave course caused by a hypothetical dam failure, the information and warning system has been proposed.
