Ruhr (river) Ruhr (river) __notoc__ The Ruhr is a river in western Germany (North Rhine-Westphalia), a right tributary (east-side) of the Rhine. The source of the Ruhr is near the town of Winterberg in the mountainous Sauerland region, at an elevation of approximately 2,200 feet (670 m). It flows into the lower Rhine at an elevation of only 56 feet (17 m) in the municipal area of Duisburg. Its total length is , its average discharge is 79 m³/s (cubic metres per second) at Mülheim near its mouth. Thus, its discharge is, for example, comparable to that of the river Ems in
Rhine-Ruhr 20th century. Since the Middle Ages, Cologne, Dortmund and other cities were important regional trading cities, but during the 19th century the city of Düsseldorf grew to become the administrative center of the region and since 1945 its political capital. Today, the Rhine-Ruhr metropolitan region accounts for roughly 15% of the GDP of the German economy, which would place it as the 4th largest GDP of metropolitan area in the European Union and the 16th largest GDP in the world. Despite this size, the Rhine-Ruhr region as a whole often lacks international competitiveness because it lacks a unified presentation. Cities