The Emschergenossenschaft is the oldest and biggest public German water board, („Wasserwirtschaftsverband”) located in Essen (North Rhine-Westphalia/Germany) and responsible for the 865 km2 Emscher catchment with 2.2 million citizens. The main tasks are wastewater discharge and treatment, flood protection, groundwater management, settlement of claims caused by hard coal mining, river restoration and protection of ecosystems.
History
Origins and early development
In the North of Germany the merging of adjoining land owners along rivers and creeks in cooperatives had a long tradition from the 13th century on. In the German Rhine catchment, downstream of Cologne, the industrialization in the 19th century was leading to a renaissance of the alliance ideas. Until the middle of the 19th century the river Emscher (running from the spring close to Dortmund in western direction to the Rhine) was a small meandering lowland river of 109 km and the villages along the river had only a few thousand citizens. The improvement of steam engines and the construction of the Cologne-Minden trunk line in the 1840s enabled the economic development and the excavation of vertical mine shafts in the northern Ruhr from the 1850s on. This resulted in severe environment and health problems due to mining subsidence: The hard coal excavation hundreds of meters underground caused sinking at the surface. In some areas the mining lead, over a period of 100 years, to 30 m of mining-induced subsidence. The Emscher catchment area suffered from “subsidence funnels” where waste water, surface run-off and water from the creeks gathered and stagnated. From the river Ruhr (running in parallel in the south of the Emscher) water was supplied by pumping stations to the northern cities from the 1870s on but the water carried germs and contaminations, too. Along the Emscher and its tributaries putrid smell, polluted water and flooding were not only restraining economic developments but also causing diseases and epidemics like typhus and malaria. From 1885 on legislative initiatives started to develop catchment-wide solutions and finally in 1899 the mining companies, industrial players and the Lord Mayors of the growing cities established the Emschergenossenschaft to organize the regional water drainage. In the same year the water supply was improved by the foundation of the Ruhrtalsperrenverein that was responsible for the construction and operation of drinking water basins to support industry and citizens.
The municipalities were responsible for the inner city drainage systems and interconnection points were jointly defined where the Emschergenossenschaft took over responsibility. Those were normally the sub catchment parts where underground sewer systems were impossible as the mining subsidence would have caused damage continuously and waste water would have infiltrated in groundwater and soil.
In the following years – based on the Emschergenossenschaft act from 1904, a special water board act – the technical initial equipment and extension of the river and tributaries took place in the 865 km2 catchment area, cutting the meanders (the Emscher was shortened from 109 km to today 81 km), deepening the runways and lining them with concrete, constructing dikes and pumping stations, relocating the Emscher mouth to guarantee downward slope and establishing waste water treatment plants. All discharge from industry, mines and households as well as rain, surface water and natural discharge were collected and drained in these new “concrete streams”. All costs were divided between the “users” of the Emscher system, depending on the volume and load of waste water or drainage capacity or causer (for example the mining companies).
Between 1906 and 1914 the catchment area changed completely as in parallel to the technical transformation of the river system with 7.000 hectares drained land the shipping waterway Rhine-Herne Canal was constructed over a stretch of 46 km to connect the coal and steel district via the Rhine to the North Sea. This waterway was located partly in the former Emscher course and is often only separated by a dyke from the Emscher.
Progressing coal mining aggravated environmental problems and permanent pumping and re-construction was needed since starting the initial equipment. In the 1920s the Emschergenossenschaft operated 30 waste water treatment plants but changed the system to more centralized solutions in the following years, starting 1927 with a facility in Bottrop and (after the second relocation of the Emscher mouth 1949) the development of the central treatment plant Emscher mouth in the 1970s.