The 15 km Floßgraben timber transport ditch has survived almost completely intact. It was built between 1556 and 1559, primarily to supply wood to the Schneeberg and Schlema smelteries. Water from the Zwickauer Mulde river was later used to drive various mills and as raw water. The timber transport ditch begins at the weir house near Albernau, which was completed in 1559 and was home to the Floß- und Rechenmeister (timber transport/weir master). It runs along the left slope of the Zwickauer Mulde river, passing various mineworkings, including as an abandoned tungsten pit (closed down in 1956) and several adit mouths, and continuing on to Schlema via the town of Aue. At Schlema, the water is channelled via cascades into the new spa park. A track runs beside the timber transport ditch (which is 1-1.5 metres wide); this forms part of the cycling and hiking trail network of Bockau, Aue and Bad Schlema.