Until the 19th century, not just the Isar River and its natural branches but also the “Stadtbäche”, artificial canals, provided Munich with water for drinking, commerce, waste discharge, defense, ostentatious display and for other functions. In particular, the streams were the main transport route and offered hydropower for many mills and other hydropower-dependent facilities in the Preindustrial and Early Industrial Ages. The Isar—an alpine river—transported large amounts of gravel and would often change its course. Regularly, floods destroyed dams and weirs. A fair distribution of water to all users on both sides of the river was difficult to negotiate because securing constant, reliable flow was one of the biggest challenges water engineers faced. The joint development of Munich and its waters was also influenced by the conflicts between citizens and the Bavarian duke as well as by the city’s simultaneous function as ducal court of the house of Wittelsbach and as administrative centre of Bavaria. In the second half of the 19th century, when Munich became a metropolis, the city’s streams played an important role in the process of urbanisation but also became a growing problem. An unprecedented level of pollution from increasing industrial activities and growing population required action. Solutions had to be found for the many tasks that were fulfilled by the city’s streams. As in many other cities, electricity and railroads as new technologies of the Industrial Age enabled Munich’s inhabitants to replace the essential local functions of the river. The artificial canals could then be filled in and most natural branches of the Isar disappeared below ground. One of the defining characteristics of the city, its unique reliance on canals, had ceased to be.