The Emscher river

The Emscher river rises in the eastern Ruhr, crossing the region in a westerly direction before flowing into the Rhine. In doing so, the canalised river course intersected the central Ruhr area.

At the end of the 19th century and beginning of the 20th century, the iron, steel and mining industries were established along the river. Consequently, the Emscher river gained an industrialised function – the intake of wastewater and its transfer in the direction of the mouth of the Rhine. Due to the subsidence experienced by large areas along the Emscher due to mining operations and the above-average proportion of sealed areas in the central Ruhr area, even by the end of the 19th Century, floods were occurring and left entire urban districts and industrial companies under water. In response to this situation, cities, municipalities and industrial companies formed a cooperative at this time aimed at regulating the course of the Emscher and, thus, to further guarantee disposal of industrial wastewater and to control flood situations. A system of drainage canals was built, 360 km in length, which covered the river's tributaries as well its main course. For decades, the system conveyed mainly untreated wastewater, not separated from surface water, above ground from east to west through the Ruhr area.

The decline of industry also saw the Emscher lose many of its functions. In model projects, the IBA Emscher Park began to develop individual renaturation projects for the Emscher tributaries in conjunction with the Emscher Genossenschaft, Kommunalverband Ruhrgebiet and participating cities. As a consequence of these stimuli and following the IBA Emscher Park, the Emscher has been rehabilitated as one of the largest building projects in Europe. The replacement of many drainage canals, the separation of wastewater and pure water into individual, underground drains (partly covered), the renaturation of canal banks and their incorporation into quality urban environments should eventually lead to the restoration of a green Emscher valley at the heart of the Ruhr area.