The Ruhr region is one of Europe's most important conurbation. More than 5 million people live and work here - accounting for around 6.5 per cent of Germany's population.
The region takes its name from the river flowing along its southern boundary - the Ruhr. Judging from its length, its flow and the size of its catchment area, the Ruhr is a rather small river. It is 219 kilometres long and the mean flow at its mouth amounts to around 80 cubic metres per second - much lower than for instance the Rhine's mean flow of 2,510 cubic metres per second at Duisburg. The Ruhr's catchment area covers 4,485 square kilometres, around five times the size of Berlin or double the size of the Saarland federal state. The Ruhr originates 674 metres above sea level from the Ruhrkopf mountain in the Sauerland region (near Winterberg) and flows into the Rhine near Duisburg, 17 metres above sea level. Its most important tributaries are the Lenne, the Volme, the Möhne, the Wenne and the Röhr.
In the industrial area's section to the right of the Rhine and in the Sauerland region, the Ruhr and its tributaries supply 4.6 million people as well as businesses and industrial enterprises with drinking and industrial water. The industrial area features an extremely high population density, which is why water consumption is seven times as high as the national average. This calls for special measures to ensure optimum supply of drinking water and sewage disposal, two aspects which count among the most important foundations for the coexistence of a large number of people. The business and industrial communities as well cannot operate without powerful and reliable water management.