The Rosice-Oslavany coal-mining district, which spans 22 km(2), is a typical example of a historical mining site where mine works flooded after closure. Mining lasted for 240 years, with shafts reaching depths of 1500 m. A single drainage adit dewatered the mine workings, which were all hydraulically connected. Mine water discharges have stabilized at an average value of 50aEuro'60 L/s, significantly exceeding the projected discharge value of 30 L/s. Groundwater flow was modeled to understand the discrepancy between the expected and observed discharges. Comparison of modeling scenarios have confirmed the importance of the hydraulic connection of the mine workings to overlying streams; stream seepage was identified as the key source of the influent mine water. The measured and simulated mine water discharges correlated well with the seepage characteristics of the surface streams.