A river in constant change
The about 80km long river Emscher in the heart of the Ruhr Area is the object of a generation project of the EMSCHERGENOSSENSCHAFT, in which the river will be transformed back from being an open sewer to a natural river. The renaturation of the Emscher system is a task of immense dimensions – in terms of the technology needed and of course in terms of finances. With an overall investment volume of €4.5 billion and a projected time schedule of several decades, the Emscher renaturation project is one of the largest infrastructure projects in Europe. Since the start of the Emscher conversion, 230 kilometres of waste water channels have been constructed, and 90 kilometres of waterways have been converted – all that in addition to the new construction or expansion of four treatment plants in Dortmund, Duisburg, Bottrop, and Dinslaken.
The official project launch of the 51 kilometres of waste water channel construction between Dortmund-Deusen and Dinslaken commenced with the ground breaking for the pump station Gelsenkirchen in 2009. The ‘Emscher Underground Fast Track”, for which a total of 15,000 sewer pipes are prepressed underground, has been underway since September 2012. With a slope of 1,5m (equal to 1,50m per km) the canal would arrive 80 meters below Dinslaken. To prevent this, the Emschergenossenschaft is building three giant pump stations: one in Gelsenkirchen, one in Bottrop, and one in Oberhausen. In these underground facilities, the water is pumped from a depth of about 40m to about 8m below ground, so it can flow off a slope again. The entire Emscher conversion is scheduled for completion in 2020.
The origins of the Emscher River
In actual fact, the Ruhr Area should be called Emscher Area. A river springs at the very heart of the region, and meanders across the core area of this internationally renowned melting pot: the Emscher. It originates in Holzwickede near Dortmund, and reaches the Rhine River around 80 kilometres further west near Dinslaken. The Emscher River unwinds like a red thread across the core area of the metropolitan region.
Over a hundred years ago, the region around the Emscher River was a thinly populated, largely untouched meadowland, complete with swampy flood plains and marsh forests. Soon after, however, industry and in particular mining was introduced to this idyllic and rural region, creating a highly industrialised conurbation. More and more coal and steel works took over the region. Population density increased
The changes in the landscape and infrastructure were not without consequence for the formerly rural river. All household and commercial waste water was unceremoniously fed straight into Emscher River and its tributaries. The river was simply not able to compensate the additional influx: High water levels repeatedly caused severe flooding, which affected entire city districts and meant terrible hygienic conditions for the inhabitants. Emschergenossenschaft was founded in 1899 to get a handle on the increasingly problematic hygiene and flood water conditions in the region, and to allow the Emscher River to flow unhindered once again. Because of the mining industry, and the associated ground subsidence, however, it proved impossible to create a subterranean waste water system. Underground pipe lines would not have been able to withstand the pressure. A decision was therefore made to straighten the flow of the river instead, and to harness the Emscher River like a canal as it were. The ‘unruly’ Emscher became a man-made open sewer system.