Editing Isar

{{short description|River in Austria and Germany}}
{{other uses}}
{{Infobox river
 | name              = Isar
 | image             = Isar River in the north of Munich.jpeg
 | image_caption     = The river Isar near [[Munich]]
 | mapframe          = yes
 | mapframe-zoom     = 6
 | source1_location  = Eiskarlspitze, [[Alps]], [[Austria]]
 | source1_coordinates= {{coord|47|22|29|N|11|24|43|E|region:AT-7}}
 | mouth_location    = [[Danube]]
 | mouth_coordinates = {{coord|48|48|11|N|12|58|35|E|display=inline}}
 | progression       = {{RDanube}}
 | subdivision_type1 = Countries
 | subdivision_name1 = {{hlist|[[Germany]]|[[Austria]]}}
 | length_km = 291.5
 | length_ref = {{GeoQuelle|DE-BY|GV}}
 | source1_elevation = {{convert|1160|m|ft|abbr=on}}
 | discharge1_location= [[River mouth|mouth]]
 | discharge1_avg    = {{convert|174|m3/s|cuft/s|abbr=on}}
 | basin_size_km2 = 8962
 | basin_size_ref = {{GeoQuelle|DE-BY|GV}}
 | extra             = 
}}

The '''Isar''' ({{IPA|de|ˈiːzaʁ|pron|De-Isar.ogg}}) is a [[river]] in [[Austria]] and in [[Bavaria]], [[Germany]]. Its source is in the [[Karwendel]] mountain range of the [[Alps]]. The Isar river enters Germany near [[Mittenwald]] and flows through [[Krün]], [[Wallgau]], [[Bad Tölz]], [[Munich]], and [[Landshut]] before reaching the [[Danube]] near [[Deggendorf]]. With 295&nbsp;km length, it is among the longest rivers in Bavaria. It is Germany's second most important tributary of the Danube.

==Etymology==
One theory is that the name ''Isar'' stems from ''*es'' or ''*is'' in the [[Indo-European languages]], meaning "flowing water", and later turned into a word with a meaning narrowed to frozen water (hence English ''ice'', {{langx|de|Eis}}) in [[Proto-Germanic]]. The name itself is mentioned for the first time in 763 as ''Isura''.<ref>{{citation|author1=Martin Bitschnau | author2= Hannes Obermair|title=Tiroler Urkundenbuch. II. Abteilung: Die Urkunden zur Geschichte des Inn-, Eisack- und Pustertals. Band 1: Bis zum Jahr 1140|publisher=Universitätsverlag Wagner| pages=25–27| isbn=978-3-7030-0469-8|date=2009|language=German}}</ref> Related names include:

*[[Eisack]] / Isarco (Italy)
*[[Ésera]] (Spain)
*[[Isar, Spain|Isar]] (Spanish town, in the province of [[Burgos]])
*[[Foglia|Isauro]] (Italy)
*[[Isère (river)|Isère]] (France)
*[[Isel (river)|Isel]] (Austria)
*[[IJssel]] (Netherlands; known to Romans as ''Isala'')
*[[IJzer|IJzer/Yser]] (Belgium)
*[[Isonzo]] (Italy)
*[[Jizera (river)|Jizera]] (Czech Republic)

==Geography==
[[Image:Fluss lage isar.PNG|thumb|250px|Map of the Isar]]
[[Image:Isar fg01.jpg|thumb|250px|The river Isar north of Mittenwald, near [[Garmisch]]]]

The Isar river drains a substantial part of the [[Bavarian Alps]] and parts of the [[Karwendel]] mountains.

Apart from the larger tributaries of [[Loisach]] and [[Amper]], many smaller rivers flow into the Isar. The [[drainage basin]] contains some 9,000 square kilometers (roughly 3,500 square miles). During the winter, most of the [[Precipitation (meteorology)|precipitation]] in the Alps turns into [[snow]]. The [[snowmelt]] can result in an increased water flow down the Isar rivers during the spring meltdown. It has an average [[discharge (hydrology)|discharge]] at the [[River mouth|mouth]] of 174 m<sup>3</sup>/s.

The official source of the Isar is located in the [[Hinterau valley]] east of the village [[Scharnitz]] in the [[Karwendel mountains]] at a height above [[sea level]] of 1160m. The Lavatschbach is the Isar's longest headstream. A further source for the young Isar is the Birkkarbach, which has its sources in the [[Birkkarspitze]] mountain.

The Isar enters [[Upper Bavaria]] after ca. 22&nbsp;km just north of [[Scharnitz]] and the Isar is dammed for the first time between [[Mittenwald]] and [[Krün]]. Some of the Isar waters are channeled via the [[Rißbach]] into the [[Walchensee]], the Rißbach flow direction having been reversed. The Isar water flows into the giant downpipes of the [[Walchensee Hydroelectric Power Station]]. 200 metres lower, the Walchensee Hydroelectric Power Station releases water into the [[Kochelsee]]. From here, it flows into the river Loisach, Isar's second most important tributary.

Not far down the Isar river is a large reservoir called [[Sylvensteinsee]] was created between 1954 and 1959 to make more energy generation possible and also to avoid flooding. It is located some 12&nbsp;km south of [[Lenggries]]. It has prevented the flooding of [[Munich]], for example in 1979, 1999, and most recently in 2005. At [[Bad Tölz]], the Isar leaves the [[Bavarian Alps]]. Bad Tölz marks the river's transit from its upper to its middle course.

The Isar river flows through a sub-alpine, [[glacial]] [[morainic]] landscape towards [[Wolfratshausen]]. Just north of the town the [[Loisach]] flows into the Isar. The Isar continues on to and through the [[Munich gravel plain]] which ends within the city limits of Munich. Further downstream, the river passes [[Freising]], then the [[Amper]] flows into the Isar, its most important tributary, at [[Moosburg]]. This is where the lower course of the Isar river begins.

Passing [[Landshut]], the river makes its way through the [[Tertiary Hills]] of [[Lower Bavaria]] all the way into the [[Danube]] river. The Isar river descends some 848m to flow into the Danube, about five kilometres away from [[Deggendorf]].{{citation needed|date=July 2016}}

==History==
[[Image:Isar an der Wittelsbacher Bruecke Muenchen-4.jpg|thumb|250px|The Isar in [[Munich]], near to the [[Deutsches Museum]]]]
Among Central European habitats, Alpine rivers are ranked among those most substantially altered by humans over the past hundred years. The Isar Rivers are now protected from development.<ref>{{Cite book|title=Rivers in History: Perspectives on Waterways in Europe and North America |author1=  Christof Mauch |author2= Thomas Zeller |publisher= University of Pittsburgh Press| year=2008| isbn=9780822973416| page=212}}</ref>

At the lower Isar, between [[Moosburg]] and [[Plattling]], [[gold]] was washed from the river's sediments during the 16th and 17th century. However, there was no big economic revenue in this due to the minor amounts of the metal found in the river.{{citation needed||date=April 2023}} [[Industrialization]] gave rise to a sociotechnical system were the Isar River was economically exploited through multifunctional use. Over forty [[hydropower plant]]s were built on the Isar to electrify Bavaria.<ref>{{Cite book|title=Rivers Lost, Rivers Regained: Rethinking City-River Relations |editor1= Dieter Schott |editor2= Martin Knoll | editor3= Uwe Lubken |publisher= University of Pittsburgh Press| year=2017| isbn=9780822981596| page=}}</ref>

Following their executions on October 16, 1946, the ashes of the convicted [[Nazi Party|Nazi]] war criminals [[Joachim von Ribbentrop]], [[Hans Frank]], [[Wilhelm Keitel]], [[Alfred Jodl]], [[Alfred Rosenberg]], [[Ernst Kaltenbrunner]], [[Wilhelm Frick]], [[Arthur Seyss-Inquart]], [[Fritz Sauckel]], and [[Julius Streicher]] were scattered in the Isar, as were those of [[Hermann Göring]] who had committed suicide the previous night in defiance of his scheduled execution.{{citation needed||date=April 2023}}

In the 1940s and 1950s, the federal state of Bavaria financed the construction of major hydroelectric power plants, the Sylvenstein reservoir on the Isar was constructed between 1954 and 1959.<ref>{{Cite book|title=Rivers in History: Perspectives on Waterways in Europe and North America |author1=  Christof Mauch |author2= Thomas Zeller |publisher= University of Pittsburgh Press| year=2008| isbn=9780822973416| page=212}}</ref>

Between 2000 and 2011, the Isarplan was implemented to reduce the risk of flooding. The planning and implementation was the responsibility of the Regional Office for Water Management and the city of [[Munich]]. Embankments were removed and the river bed was widened, establishing connections to surrounding flood plains. Riverbed rock ramps were constructed so that fish could move upstream again.<ref>{{Cite book|title=Nature-Based Solutions to Climate Change Adaptation in Urban Areas |editor1= Aletta Bonn | editor2= Horst Korn | editor3= Jutta Stadler | editor4= Nadja Kabisch |publisher= Springer International Publishing| year=2017| isbn=9783319560915| page=265}}</ref>

==Environmental issues==
[[File:Windsurfer Walchensee.jpg|thumb|250px|A windsurfer near the western shores of the Walchensee]]
[[File:Laufwasserkraftwerk Muehltal.jpg|thumb|250px|Feed of river power plant Muehltal, south of [[Munich]]. [[Hydroelectricity]] supplied yearly: 70 million kilowatt hours.]]

Since the 1920s, the water of the river Isar has been used for the generation of electricity. This has had far-reaching consequences for the local fauna and flora. To provide the 28 hydroelectric power plants with enough water power the river's water is diverted several times and almost the whole river was [[canalized]]. For example, just north of [[Mittenwald]] all the river's water was diverted to the lake [[Walchensee]] in 1923 for the Walchensee hydroelectric plant. Since 1990, a small portion of the water, 4 cubic meters per second (roughly 1,100 U.S. gallons per second) is allowed to remain in the river Isar to prevent [[drought]].

The construction of the [[Sylvenstein Dam]] and numerous regulations relating to the river, pushed through in the early 19th century, have strongly enhanced its character. The construction of the Sylvenstein dam has prevented the river from overflowing its [[Bank (geography)|banks]]. Lately, there have been attempts to bring the Isar river closer back to a natural character. For example, since May 2000 the river is being re-naturalized in the southern part of the river's passage through the city of Munich. The riverbed is being widened, the banks are flattened and small gravel islands are built along with near-natural rock ramps to slow the waterflow.

Besides an improved protection against flooding the Isar river was, thus, brought into an almost natural state and this resulted in an improved quality of the recreational area within the city of [[Munich]]. The [[municipal wastewater treatment]] has also been upgraded along the river. The [[water pollution]], however, is still relatively high. Together with other cities and communities along the river Isar, Munich has set a goal to reduce the number of germs. The sewer treatment plants on the upper river are now disinfecting the [[raw sewage]] with [[ultraviolet]].

===Private environmental initiatives===
[[File:Kernkraftwerk Isar Gesamtansicht.JPG|thumb|right|A view of the nuclear power plant [[PreussenElektra (nuclear energy company)|PreussenElektra]]]]

To preserve the beauty of the Isar valley [[Gabriel von Seidl]] founded the ''Isartalverein'' in 1902. This first civil initiative from Munich purchased 90 ha of land, and today maintains more than 330&nbsp;km of hiking trails.

==References==
{{reflist}}

{{commons category|Isar}}
{{Rivers of Germany}}
{{Authority control}}

[[Category:Isar| ]]
[[Category:Isar basin| ]]
[[Category:Rivers of Bavaria]]
[[Category:Rivers of Tyrol (federal state)]]
[[Category:International rivers of Europe]]
[[Category:Rivers of Austria]]
[[Category:Rivers of Germany]]
[[Category:Braided rivers in Europe]]