City streams running through the city Munich or the Münchner Stadtbäche in German are a system of now defunct waterways which used to flow through the city of Munich. Originally natural streams branching off Munich's major waterway, the Isar River, they were later canalized and played a crucial role in the economic development of Munich in the Middle Ages up to the 19th century. Most of the streams have since been drained or culverted underground, but many of the numerous fountains within Munich today and streams in the English Garden, can be traced back to these original city streams.
The geology of Munich and its surrounding area of a gravel plain, which the Isar river runs through. As a result of this type of ground the Isar often split and changed course in the area. In the Middle Ages the Isar also branched into several side steams in the area which also changed course often.
The medieval residents of Munich harnessed these streams as an way of powering their mills and canalised the streams to fix their course. As the city grew new canal were built, taking water from the streams only to rejoin them downstream. Resultantly, Munich developed a networked of streams. Individual parts of the network were usually named after the mills along them, with a single streams often changing their name several times along its course. The streams off the left bank of the Isar were mostly branches of the Großer Stadtbach.
A variety of medieval industries grew along these streams, alongside grain mills were workshops using waterwheels for stamping, hammering, sawing, and grinding. The streams were also used to feed a moat surrounding Munich's city walls.
With the growth of the town, the streams became polluted by industry and full of waste. This made them unfit to be a source of drinking water in the city, which was instead obtained from groundwater wells. From the 16th century onwards, the water power of the streams was also used in Brunnhäuser, which were pumphouses used to extract the groundwater into water towers and then piped into houses. The waste dumped within the streams as well as sediment from the Isar often reduced the speed of the streams and the amount of power available to the pumps and mills so the canals had to be dredged often.
The onset of the industrial revolution and the invention of the steam engine led to the city streams losing their industrial function. With the construction of drinking water pipes and sewer system, the city began the process of draining or filling in defunct streams or culverting others underground. By 1900, only small sections of some streams remained above ground. Finally, in the 1960s around 17.5 km of city streams existed but several tracts were seen as an "unacceptable obstacle" to the expansion of the Munich U-bahn. Thus by 1967, only 5.5 km of city streams were left.
While the city streams originally branched directly from the Isar, today they are fed by the Isar-Werkkanal, which is diverted from the Isar at Baierbrunn, south of Munich and runs alongside the left bank of the Isar.
A part of the water from the Isar-Werkkanal downstream is redirected back into the Isar through hydroelectic plants, with the small amount remaining continuing to run into channel that used to be the Großer Stadtbach. This then runs into the old Westermühlbach. The Westermühlbach stream was preserved as it used to function as a cooling water inflow for the Müllerstraße heating plant, which was decommissioned in December 2001. The Westermühlbach still largely runs above ground today.
Near Sendlinger Tor, the Glockenbach today flows underground into the Westlicher Stadtgrabenbach, which encircles the old town to the west and surfaces for a short section in Hofgartenstraße. There it splits into the Köglmühlbach which was recreated in 1992 on its medieval course as an aesthetic feature of the Bavarian State Chancellery. The stream flows underground at the English Garden and becomes the Schwabinger Bach through the English Garden.
After the closure of the city streams a new water inlet from the Isar had to be constructed to provide water for the stream network within the English Garden. This is from an underground a canal from the Isar with its inlet at Mariannenbrücke. Today, the Fabrikbach splits into the Stadtmühlbach and the Stadtsägmühlbach, which can be seen in the courtyards of the Wacker building on Prinzregentenstraße. They flow through separate arches of the Eisbachbrücke under the same road and merge after the bridge into the English Garden and become the Eisbach, the resulting standing wave at this location is a famous surfing hotspot, the Eisbachwelle.
The Westlicher Stadtgrabenbach, which flows under Karlsplatz (Stachus) was utilised in 2011 to provide water for a District cooling system in that location.[1]