Middle Isar Canal
The Mittlere-Isar-Kanal is a channel parallel to the middle course of the Isar ; it branches off to the right of the Isar in the north of Munich and flows back into the river after about 64 kilometers at Landshut . The canal forms a power station staircase with seven hydroelectric power stations in order to use the gradient of 109 m to generate electricity.
course
The canal branches off from the Isar at the Oberföhring weir near the northern city limits of Munich, runs parallel to the river for a few kilometers and turns eastwards directly north of Unterföhring . While some of the water is branched off into the Ismaninger reservoir after a few kilometers , the Isar canal continues parallel to the reservoir. At Neufinsing , the outflowing water from the reservoir merges with the Isar Canal via a hydroelectric power station and flows further north, past Erding to the west . At the height of Munich Airport , the canal bends to the northeast and meets the Isar at Moosburg. From there it runs parallel to the Isar, into which it flows a few kilometers southwest of Landshut. In this last section there are two more reservoirs, the Moosburger and the Echinger reservoir .
The weir and the first 54 km of the canal including the 5 power plants located there belong to E.ON Wasserkraft GmbH, a subsidiary of E.ON , the last kilometers with the two Uppenborn works belong to Stadtwerke München (SWM). Of the total gradient of 109 m, 88 m are attributable to the E.ON power plants and 21 m to the two Uppenborn power plants.
function
The canal is not navigable and is mainly used for hydropower and as a source for the cooling water for the northern thermal power station . Up to 150 m³ / s are temporarily withdrawn from the Isar, with the main river running through Freising and between Oberföhring and the mouth of the Amper behind Moosburg occasionally suffering from a lack of water. A total of seven hydropower plants are used to generate electricity.
| power plant | power |
|---|---|
| Ismaning reservoir power plant | 1.3 MW |
| Neufinsing power plant | 8.0 MW |
| Aufkirchen power plant | 27.0 MW |
| Eitting power plant | 26.0 MW |
| Pfrombach power plant | 22.3 MW |
| Performance of the E.ON power plants | 84.6 MW |
| Uppenbornwerk 1 | 26.4 MW |
| Uppenbornwerk 2 | 18.0 MW |
| Output of the SWM power plants | 44.4 MW |
| Performance of all power plants | 129.0 MW |
The Aufkirchen, Eitting and Pfrombach power plants also produce traction current. The Uppenbornwerk 2 is a pure run-of-river power plant , as it is supposed to supply the Isar with the most constant amount of water possible. The other power plants are run-of-river power plants that are set up for threshold operation and can therefore react to fluctuations in electricity demand within a certain framework. All power plants have a so-called empty shot, i.e. H. a channel in which the water can bypass the power plant.
The Ismaninger reservoir serves both to compensate for the fluctuations in the inflow from the Isar and to store the peaks in consumption of the following power plants. The Moosburger and Echinger reservoirs are the counterpart to this, with them the larger amounts of water given off in the consumption peaks are collected, so that a constant inflow into the Isar is guaranteed.
Since May 1, 2011, E.ON power plants have no longer been monitored and controlled from the Neufinsing power plant, but from the central control center at the headquarters of E.ON Wasserkraft in Landshut. The two Uppenborn factories are centrally controlled by the Munich municipal utility.
description
The canal lies partly in cuttings in the terrain, partly between dams on the site, over long stretches but also on high dams more than 15 m above the site. It crosses the canal underpass of the Saubach flood basin leading to the Sempt flood canal at the barrage shortly before Berglern , crosses the Sempt in a culvert- like structure shortly afterwards, again below Pfrombach and a third time below the Uppenbornwerk 1, crosses a street just before Eitting and the Strogen including two separate lanes on a street near Wartenberg . A number of small streams are routed in culverts under the canal. The catchment ditch , the Dorfen Canal and the Eittinger Saubach lead to water. The sewer also receives the wastewater, which has been biologically treated in the Gut Großlappen sewage treatment plant in Munich and flows through a culvert under the Isar to the main E.ON Wasserkraft pumping station between Unterföhring and Ismaning. From this it is pumped into the five meters higher lying fish ponds of the former pond estate Birkenhof on the Ismaninger reservoir and partly directly into the reservoir.
The channel is built for a water flow of 125 to 150 m³ / s. It has different cross-sections depending on the terrain. It is between 3.8 m and 18.3 m wide at the bottom and between 23 m and 34 m wide at the water level. Its depth varies accordingly between 4.4 m and 7 m in the narrow stretches, especially in the first stretch up to the fish ponds on the reservoir, where the canal had to be kept narrow for reasons of space. The slopes are continuously steep with slopes of 1: 1.5 or 1: 2. Both the slopes and the bottom were originally concreted. During the renovation of the first section in 2005, a bitumen seal was partially applied. During the renovation of sections 2, 3 and 4b in 2009, concrete was used again in addition to plastic sheeting.
In cold winters, attempts have always been made to delay the threat of icing by breaking up the ice layer with the appropriate positions of the weirs and gates. Since the northern thermal power station in Unterföhring has taken its cooling water from the sewer and reintroduced it into it, however, no more ice problems have occurred.
history
idea
The idea of using a canal to use the height difference of a good 80 meters between Munich and Moosburg to generate electricity came from Oskar von Miller . However, it was initially not pursued further because at the beginning of the 20th century there were different considerations as to whether and how the Bavarian waters should be converted and expanded to generate electrical energy. The Bavarian State Ministry of the Interior caused the end of 1917, that various banks and some industrial companies to the Middle Isar GmbH merged to the slope of 88 m exploit between Munich and Moosburg. The initial idea was to build canals with a capacity of 95 m³ / s and various barrages along the Isar. The city of Munich, which already operated the Uppenborn plant near Moosburg, should be involved in the project.
planning
In February 1918, Theodor Rümelin was appointed director of Mittlere Isar GmbH with the task of planning the project. His design not only envisaged the canal in its current form with the weir and the four power plants at that time, but also contained a number of other functions: The Ismaninger reservoir was to be created to compensate for the different water levels of the Isar. The groundwater of the Munich gravel plain in the 30,000 hectare Erdinger Moos was to be lowered with a deep interception ditch . The aim was not only to gain new arable land, but also to protect the canal from icing in winter by the warmer groundwater. In addition, around 30 fish ponds were to be created on the Ismaninger reservoir in order to further purify the Munich wastewater, which is still to be built in the Gut Großlappen sewage treatment plant , and at the same time improve the food supply for the population. Finally, the Moosburg compensation pond was to be created in order to ensure an even outflow from the canal to the old Uppenborn plant. The problems that would arise for the Isar from the extensive drainage of the water were seen. But it was considered justifiable in view of the many advantages of the canal. Various fish deaths that occurred because the sewage treatment plant had not yet been completed did nothing to change this. The draining of the Erdinger Moos , on the other hand, was seen only positively; today's, more ecologically differentiated approach was unknown at the time.
In accordance with the ideas discussed at the time to create a network of shipping canals in southern Germany , Rümelin designed the planning in such a way that the possibility of using the canal for shipping was not excluded. The locks and escape channels required to bypass the power plants were, however, postponed from the start.
Construction phases
Rümelin was able to complete this extensive planning at the beginning of 1919. They then passed into the possession of the Bavarian state, which awarded the first construction lot in April 1919 to combat unemployment, after a unanimous decision by the finance committee of the Bavarian state parliament had accepted Rümelin's planning on March 25, 1919 and endorsed its implementation by the state . As a member of the directorate for the state development of the Middle Isar, Rümelin was responsible for project management and site management. But he died at the end of 1920 at the age of only 43 years. Shortly afterwards, on January 5, 1921, the Free State of Bavaria founded Mittlere Isar AG and Walchenseewerk AG to build and operate both projects.
Between 1920 and 1924 the Oberföhring weir , the Ismaninger reservoir and the Neufinsing , Aufkirchen and Eitting power plants were built . In this first construction phase, the canal initially ended above the village of Berglern , where its water was returned to the Isar through the Sempt flood canal . In the second construction phase between 1926 and 1929, the canal was extended to the area of the Uppenbornwerk of the municipal electricity works in Munich, the Moosburg compensation pond was created and the Pfrombach power plant was built as the fourth stage.
Up to 8100 workers were employed at the same time during the construction of the Middle Isar Canal. Mittlere Isar AG built and operated various railways to transport them, but also to transport large quantities of material and the heavy parts of the technical systems of the power plants. The earth masses were transported with the field railways on the bottom of the canal sections. The Moosbahn with a gauge of 600 mm carried workers and materials from Kufsteiner Platz in Munich to the construction site of the Neufinsing power plant. The Altenerding – Pfrombach railway ran from Altenerding station via Aufkirchen and Niederding along the canal to Pfrombach and was in operation until 1967. The Tivoli power plant in Munich was expanded to supply the numerous electrically operated construction machines and a 20 kV line was laid along the canal route.
The construction of the Gut Großlappen sewage treatment plant between 1920 and 1926, which Mittlere Isar AG carried out on the site acquired by the City of Munich in 1916, was closely connected with the construction of the canal.
In 1929, Mittlere Isar AG completed the second construction phase and thus the canal belonging to it. The extension took place in two stages by the Stadtwerke München. In 1930 the power plant known today as Uppenborn 1 was put into operation and the Echinger reservoir was created. At the Hofham barrier weir ( 48 ° 30 ′ 35.2 ″ N , 12 ° 4 ′ 34.5 ″ E ) the water flowed evenly back into the Isar via an outlet weir. With the construction of the Uppenborn 2 power plant about 8 km below the Uppenborn 1 plant from 1949 to 1951, the canal was extended again. It flows back into the Isar just above Landshut .
Dam break
On July 12, 1931 between 11 a.m. and 12 noon, a high-lying dam on the Mittlere-Isar-Kanal broke at the level of Wartenberg and Langenpreising. The canal water in the section between the Eitting and Pfrombach power plants flooded the area until the weir at Berglern was closed after about three hours.
Bridges
The canal and its power stations suffered almost no damage during World War II . However, most of the 45 bridges over the canal were blown up by the German side in the last days of the war in order to stop the advance of American troops. As with all Munich bridges, the demolition could only be averted on the four bridges to Oberföhringer Isarinsel. Many of the destroyed bridges were replaced by a uniform type of bridge consisting of two concrete arches with elevated road surfaces.
Renovations
Apart from the breach of the dam, the sewer was never emptied until the partial renovations in 2005 and 2009, during which the parts of the Aufkirchen and Eitting power plants that were otherwise always under water could also be renovated.
literature
- Cornelia Oelwein: Between Goldach and Seebach . The history of the Goldachhof and moss cultivation in Ismaning. Verlag Franz Schiermeier, Munich 2013, ISBN 978-3-943866-22-3 .
Web links
swell
- ↑ More water in the Middle Isar ( Memento of the original from January 6, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. on the website of the Munich Water Management Authority
- ↑ E.ON bird's eye view ( Memento of the original dated December 5, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ SWM: Energy from Water (p. 16: Uppenbornwerke ) ( Memento of the original of July 8, 2011 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 3.5 MB)
- ^ E. Mattern: Hydropower Plants in Bavaria III; The Middle Isar . Digital copy: 022. Zentralblatt der Bauverwaltung 43. 1923, No. 41/42 = p. 242–248, p. 245
- ↑ E.ON Wasserkraft: Repair of the Middle Isar Canal ( Memento from January 22, 2013 in the web archive archive.today )
- ↑ R. Schmick: Expansion of the Bavarian hydropower digitized: 092. Zentralblatt der Bauverwaltung 37.1917, No. 97 = p. 581-588, p. 585
- ^ E. Mattern: The opening of the "Middle Isar" . Digitized: 037. Zentralblatt der Bauverwaltung 45. 1925, No. 35 = pp. 421–440, p. 427
- ^ E. Mattern: The expansion of the Bavarian hydropower digitized: 040. Zentralblatt der Bauverwaltung 39. 1919, No. 47 = p. 257–264, p. 261, with a map of the proposed canals
- ^ E. Mattern: The expansion of canals for several economic purposes, especially for power generation and shipping. Digitized: 091. Zentralblatt der Bauverwaltung 39. 1919, No. 99 = S. 589-596, S. 593
- ^ Obituary for Th. Rümelin . Digitized: 096. Zentralblatt der Bauverwaltung 40. 1920, No. 97 = pp. 605–612
- ^ E. Mattern: The expansion of the Bavarian hydropower digitized: 040. Zentralblatt der Bauverwaltung 39. 1919, No. 47 = p. 257–264, p. 261
- ^ Stephan Deutinger: Mittlere Isar AG in: Historisches Lexikon Bayerns
- ^ Werkbahn Mittlere Isar AG on Isartalbahn.de
- ↑ Großlappen sewage treatment plant Munich I on “freimann-froettmaning.de”
- ↑ Photos of the break in the Middle Isar Canal
- ↑ ( Page no longer available , search in web archives: Roland Wach: Repair of the solid structures of the Aufkirchen and Eitting power plants (PDF; 121 kB) )
