For the water supply of the Ehrenfriedersdorf mining installations, the 5.5 km long Röhrgraben (ditch) was built between 1396 and 1404. It is one of the oldest man-made water ditches constructed for mining in the Ore Mountains. Until the end of mining in Ehrenfriedersdorf in 1990, the Röhrgraben also provided water for tin dressing and was then the oldest man-made water ditch which was still in use in Germany.
