The Emscher is a tributary of the river Rhine catchment, running through the densely populated Ruhr area in Germany. Its catchment covers 865 km2. Since the 19th century the Emscher and its tributaries were systematically developed as open wastewater sewers due to industrialisation and extensive charcoal mining. 40% of the area became polders because of heavy subsidence due to mining. The bed of the Emscher and its tributaries were lowered and dykes were built over long stretches, in order to protect the cities from flooding. Now, the integrated river basin management for the Emscher region aims at the revitalisation of the Emscher and its tributaries as a nature-like urban river system. More information