The Emschergenossenschaft was founded in Bochum in 1899. Since then, its tasks have included the maintenance of the Emscher, wastewater disposal and treatment, and flood protection. Due to the subsidence in the Ruhr area caused by mining, underground canals were not possible in the past, as they would have been damaged by subsidence. Therefore, the Emscher was used as the central river of the Ruhr area and its tributaries were used as open sewage courses. However, the situation has changed since the late 1980s and early 1990s. After mining moved north, there is no longer any fear of subsidence, so underground sewage canals can now be built. Since 1992, the Emschergenossenschaft has been planning and implementing the Emscher conversion. Every body of water has an underground counterpart through which the wastewater is drained to the sewage treatment plants. The above-ground streams are thus free of wastewater and can then be converted in a natural way: the concrete base shells are removed, the embankments are made wider and more versatile. Where space allows, the once technically straightened rivers are being given a more winding course again. Over a period of 30 years, the Emschergenossenschaft invested almost 5.5 billion euros. Around 430 kilometers of canals have been laid, and almost 150 of the 328 kilometers of watercourses have already been ecologically improved. The upper reaches of the Emscher and its tributaries in Dortmund have been completely free of sewage over a length of around 24 kilometers since the beginning of 2010 - and have now largely been renaturalized, as have the former Emscher arms, the Alte Emscher and Kleine Emscher, in the Duisburg area. With the Emscher conversion, the Emschergenossenschaft is not only implementing a purely water management project to free the regional waters from sewage, but is also actively combating the effects of climate change. The renaturalized waters, including the new flood retention areas, offer excellent flood protection in the event of heavy rain, and the new green spaces along the banks ensure a better microclimate in hot periods. As part of the Emscher conversion, the Emschergenossenschaft is creating green-blue infrastructures that are worth experiencing and experiencing: former industrial roads are being turned into footpaths and cycle paths, and more than 120 km have now been created along the Emscher - including the Emscher path between Holzwickede and Dinslaken. The Emscher conversion not only brings added value for people and nature, but is also a driver for the urban development of the region.