Ruhr (river)
The river begins its journey near the town of Winterberg in the mountainous Sauerland region. It rises at an elevation of approximately 360 meters above sea level. This high starting point sets the stage for a long descent toward the north. The water travels through towns like Meschede, Arnsberg, and Wickede before reaching the industrial heart. Its total length spans roughly 219 kilometers across western Germany. At Mülheim, just before meeting the Rhine, the average discharge reaches 45 cubic meters per second. This volume matches that of the River Thames in the United Kingdom or the Ems in Northern Germany. The final stretch flows into the lower Rhine within the municipal area of Duisburg. Here, the elevation drops to only about 20 meters. The river marks the southern limit of the Ruhr area as it passes Hagen, Dortmund, Herdecke, Wetter, Witten, Bochum, Hattingen, Essen, and Mülheim.
Most factories were located along this valley during the early- to mid-20th century. The region became Germany's primary industrial zone by the 1900s. Heavy industry thrived here with coal mines and steel mills lining the banks. In 1923, French forces occupied the Ruhr due to the Weimar Republic's failure to continue paying reparations from World War I. This occupation lasted until 1924. Passive resistance saw production in the factories grind to a halt. Workers refused to cooperate with the foreign troops. As a result, the German hyperinflation crisis grew even worse. Prices for basic goods skyrocketed while the currency lost its value rapidly. The political consequences rippled through the entire nation. Economic collapse followed the shutdown of these vital manufacturing centers. The conflict highlighted the deep tensions between France and Germany after the Great War.
Two of the dams on the Ruhr became targets for Operation Chastise during the Second World War. The Möhne Dam and the Sorpe Dam stood as critical infrastructure for German wartime production capabilities. Special bouncing bombs were developed specifically to take out these structures. The goal was to flood the valley and seriously affect the industries there. These weapons bounced across the water before striking the dam walls. The resulting explosions breached the concrete barriers and released massive amounts of water. The story was told in a book published in 1951. A popular film adaptation titled The Dam Busters arrived in 1955. This cinematic retelling brought the engineering feat and military strategy to global audiences. The operation remains one of the most famous air raids of the war. It demonstrated how precise targeting could cripple an enemy's industrial output.
Five artificial lakes now exist along the river for leisure activities. Hengsteysee sits between Dortmund and Hagen with a surface area of 1.36 square kilometers. Its weir stands at a height of 4.5 meters. Harkortsee lies between Herdecke and Wetter covering 1.37 square kilometers. The weir here reaches 7.8 meters high. Kemnader See flows between Witten and Bochum spanning 1.25 square kilometers. Baldeneysee occupies Essen-Werden with a larger surface area of 2.64 square kilometers. Kettwiger See rests in Essen-Kettwig covering just 0.55 square kilometers. These reservoirs serve as centers for swimming, boating, and fishing today. They transformed former industrial zones into spaces for public enjoyment. Families visit these sites during summer months to escape city heat. The water levels fluctuate based on seasonal rainfall and dam operations. Each lake maintains its own unique character while sharing the same river system.
The Ruhr was extensively used by adjacent factories for cooling-water throughout history. Industrial discharge heavily contaminated the river during the 19th and 20th century. Large sections of the river were straightened changing the habitat significantly. This alteration led to a decline in various fish species including brook trout and related salmonids. Dozens of smaller and larger dams prevented migratory species like salmon from ascending or descending the river. Salmon have not been observed in the river in decades. Stocks of the European eel have dwindled to near extinction locally. Both eel and brook trout stocks rely heavily on release of juveniles as part of conservation efforts. The natural flow patterns were disrupted by concrete barriers built for power generation. Pollution from chemical plants further degraded water quality over many years. The ecosystem suffered severe damage before modern awareness took hold.
Since 2013, the district government of Arnsberg has invested heavily into renaturation efforts. Funding comes partially from grants of the European Union aimed at restoring natural habitats. Projects include removal or addition of bypasses to barriers such as dams along the whole river. These changes re-enable natural fish migration that had been blocked for generations. The river bed is widened substantially in sections reducing depth and slowing down water flow. Slower currents enable natural reproduction of native fish and insects. Two sections of the renaturation have been completed in Wickede and Witten. Two more projects are currently underway across other districts. Eighteen additional projects remain in planning stages as of now. The river is not fully passable for migratory fish yet despite progress. Conservationists monitor water quality and species recovery rates closely. The goal remains a return to pre-industrial ecological balance.
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Common questions
Where does the Ruhr river begin and at what elevation?
The river begins its journey near the town of Winterberg in the mountainous Sauerland region. It rises at an elevation of approximately 360 meters above sea level.
When did French forces occupy the Ruhr valley during the 20th century?
French forces occupied the Ruhr due to the Weimar Republic's failure to continue paying reparations from World War I starting in 1923. This occupation lasted until 1924.
Which dams on the Ruhr were targeted by Operation Chastise in the Second World War?
Two of the dams on the Ruhr became targets for Operation Chastise during the Second World War. The Möhne Dam and the Sorpe Dam stood as critical infrastructure for German wartime production capabilities.
How many artificial lakes exist along the Ruhr river today?
Five artificial lakes now exist along the river for leisure activities. Hengsteysee, Harkortsee, Kemnader See, Baldeneysee, and Kettwiger See serve as centers for swimming, boating, and fishing today.
Why have salmon not been observed in the Ruhr river in decades?
Dozens of smaller and larger dams prevented migratory species like salmon from ascending or descending the river. Salmon have not been observed in the river in decades due to these concrete barriers built for power generation.