{{short description|River in Switzerland, Austria and Germany}} {{use dmy dates |date=September 2021}} {{Infobox river |name = Inn |name_other = {{langx|rm|En}} |image = UnterinntalWest.JPG |image_caption = Lower Inn valley from Rattenberg castle |mapframe = yes |mapframe-zoom = 6 |source1_location = Swiss Alps (Lägh dal Lunghin) |source1_elevation = {{convert|2484|m|ft|abbr=on}} |source1_coordinates = {{coord|46.41673|9.67645}} |mouth_location = Danube (Passau) |mouth_elevation = {{convert|291|m|ft|abbr=on}} |mouth_coordinates = {{coord|48.57353|13.47713|display=inline,title}} |progression = {{RDanube}} |subdivision_type1 = Countries |subdivision_name1 = {{ubl|Switzerland|Austria|Germany}} |subdivision_type2 = Cities |subdivision_name2 = {{hlist|St. Moritz|Scuol|Landeck|Innsbruck|Wörgl|Kufstein|Rosenheim|Wasserburg am Inn|Mühldorf am Inn|Braunau am Inn|Schärding|Passau}} | length_km = 518.5 | length_ref = {{GeoQuelle|DE-BY|GV}} |discharge1_location= mouth |discharge1_avg = {{convert|735|m3/s|abbr=on}} | basin_size_km2 = 26053 | basin_size_ref = {{GeoQuelle|DE-BY|GV}} | extra = }}

thumb|265px|Map highlighting the Inn River The '''Inn''' ({{IPA|de|ɪn|-|De-Inn.ogg}}; {{langx|la|Aenus}};<ref>{{cite book |title=Barrington Atlas of the Greek and Roman World: Map-By-Map Directory |editor=Richard J.A. Talbert |volume=I |year=2000 |publisher=Princeton University Press |location=Princeton, NJ and Oxford, UK |isbn=0691049459 |page=171 }}</ref> {{langx|rm|En}}) is a river in Switzerland, Austria and Germany. The {{convert|518|km|abbr=on}} long river is a right tributary of the Danube, being the third largest tributary of the Danube by discharge. The highest point of its drainage basin is the summit of Piz Bernina at {{convert|4049|m|abbr=on|sp=us}}. The Engadine, the valley of the En, is the only Swiss valley whose waters end up in the Black Sea (via the Danube).

==Etymology== The name Inn is derived from the old Celtic words ''en'' and ''enios'', meaning ''water''. In a document of 1338, the river was named ''Wasser'' (German for water). The first written mention from the years 105 to 109 (Publii Corneli Taciti historiarium liber tertius) reads: "''... Sextilius Felix... ad occupandam ripam Aeni fluminis, quod Raetos Noricosque interfluit, missus...''" ("... Sextilius Felix was sent to capture the banks of the Inn, which flows between the Rhaetian people and the Noric people.")<ref>"Wolf-Armin Frhr. v. Reitzenstein: Lexikon bayerischer Ortsnamen. Herkunft und Bedeutung. C.H.Beck, Munich 2006</ref> The river is also mentioned by other authors of the Roman Empire as ''Ainos'' (Greek) or ''Aenus'' (Latin). In medieval Latin it was written as ''Enus'' or ''Oenus''. The change in the old Bavarian language from ''e'' to ''i'' turned Enus to ''In''. Until the 17th century, it was written ''In'' or ''Yn'', but also ''Ihn'' or ''Yhn''. The double-n appeared only in the 16th century, for example in the Tyrolian Landreim of 1557, and since the 18th century this spelling and pronunciation with a short vowel has been customary.<ref name="stolz">Otto Stolz: ''Geschichtskunde der Gewässer Tirols.'' Schlern-Schriften, Band&nbsp;32, Innsbruck 1932, S.&nbsp;6–14 und 83–88 ([http://dza.tessmann.it/tessmannPortal/Medium/Seite/12721/19 Digitalisat])</ref>

The mentions in Roman times refer to the lower course. The Tyrolean section was first called Aenus by Venantius Fortunatus in the 6th century. The name Engadin and the Romansh name ''En'' indicate that the upper reaches of the river have long been called this way. Even though it was occasionally believed that the Inn originated near the Adige at the Reschen Pass, since the 16th century at the latest the origin has been seen uniformly in the area of the lakes at the Maloja Pass.<ref name="stolz" />

A connection may exist between the name Inn and the name of the French river Ain.<ref>Arnaud Vendryes: ''L'Ain : le nom d'une rivière à travers les sources.'' In: Société d'Emulation du Jura, Travaux 2015, S. 147–168</ref>

==Geography== The source of the Inn is located in the Swiss Alps, west of St. Moritz in the Engadine region, which is named after the river (Romansh ''Engiadina''; Latin ''vallis Eniatina''). Shortly after it leaves its source, the Inn flows through the largest lakes on its course, Lake Sils and Lake Silvaplana. It runs north-eastwards, entering Austria, and from Landeck eastwards through the Austrian state of Tyrol and its capital, Innsbruck (''bridge over the Inn''), and crosses the border into Bavaria near Kufstein.

On Bavarian territory the river runs northwards and passes Rosenheim, Wasserburg am Inn, and Waldkraiburg; then it turns east, runs through Mühldorf and Neuötting and is enlarged by two major tributaries, the Alz and the Salzach. From here to the Danube, it forms the border between Germany (Bavaria) and Austria (Upper Austria). Towns on this last section of the river are Marktl am Inn, Simbach on Inn, Braunau am Inn and Schärding.

In Passau the Inn finally enters the Danube (as does the river Ilz there). Although the Inn has a greater average flow than the Danube when they converge in Passau, and its watershed contains the Piz Bernina, the highest point in the Danube watershed, the Inn is considered a tributary of the Danube, which has a greater length, drains a larger surface area, and has a more consistent flow. The Inn is the only river originating in Switzerland that ends in the Black Sea (via the Danube).

===Tributaries=== [[File:W Inntal.JPG|thumb|600px|center|View of the Lower Inn Valley. On the right is the entrance to the Ziller Valley.]]{{clear|left}} * Right tributaries (in downstream order): <!--La Clozza, Tasnan, La Brancla?-->Flaz, Spöl, Clemgia, Faggenbach, Pitzbach, Ötztaler Ache, Melach, Sill, Ziller, Alpbach, Wildschönauer Ache, Brixentaler Ache, Weißache, Kaiserbach, Rohrdorfer Ache, Sims, Murn, Alz, Salzach, Enknach, Mattig, Ach, Hartbach, Antiesen, Pram * Left tributaries (in downstream order; two different rivers called Rott exist): Beverin, Schergenbach, Sanna, Gurglbach, Höttinger Bach, Mühlauer Bach, Brandenberger Ache, Kieferbach, Auerbach, Kirchbach, Mangfall, Rott, Attel, Isen, Rott

== Flow == The average discharge at the mouth of the Inn is {{cvt|735|m3/s}}.{{GeoSource|Danube||12}} {{center|1='''Average monthly flow (m³/s) of the Inn in Passau'''<br /> <span style="font-size:smaller">Years 1921/2006<ref name="hnd"/></span>}} {{center|1=<timeline> Colors= id:lightgrey value:gray(0.8) id:darkgrey value:gray(0.3) id:sfondo value:rgb(1,1,1) id:barra value:rgb(0.6,0.8,0.9)

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PlotData= color:skyblue width:30 shift:(-15,-15) fontsize:M anchor:till bar:1 from:0 till: 411 text: 411 bar:2 from:0 till: 436 text: 436 bar:3 from:0 till: 534 text: 534 bar:4 from:0 till: 717 text: 717 bar:5 from:0 till:1030 text:1030 bar:6 from:0 till:1260 text:1260 bar:7 from:0 till:1190 text:1190 bar:8 from:0 till:1020 text:1020 bar:9 from:0 till: 756 text: 756 bar:10 from:0 till:570 text: 570 bar:11 from:0 till:493 text: 493 bar:12 from:0 till:450 text: 450

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=== 2013 flood === {{Main|2013 European floods}} The Old City of Passau during the flood|thumb Water level marks on the Town Hall in Passau|thumb On 3 June 2013 the discharge of the Inn in Passau reached {{convert|6,820|m3/s|abbr=on}}<ref name="hnd"/> and the water levels reached {{convert|12.85|m|abbr=on}}, the highest recorded historic flood level since 1501.<ref name="in"/> The historic centre of Passau, where the Danube, Inn and Ilz converge, was flooded severely.

== Hydroelectric power plants == Currently, there are 24 hydroelectric power plants on the Inn. 17 of them are operated by Verbund AG.<ref name="ve"/> The power plants are listed beginning at the headwaters:

{|class="wikitable sortable" ! Dam ! Nameplate capacity (MW) ! Annual generation (Mio. kwh) |- | Islas<ref name="st"/> | 4.3 | 17 |- | Ova Spin<ref name="en1"/> | 50 | 100 |- | Pradella<ref name="en2"/> | 288 | 1,000 |- | Martina | 70 | 290 |- | Imst<ref name="ti1"/> | 89 | 550 |- | Kirchbichl<ref name="ti2"/> | 19.3 | 131 |- | Langkampfen<ref name="ti3"/> | 31.5 | 169 |- | Oberaudorf-Ebbs | 60 | 268 |- | Nussdorf | 48 | 245.8 |- | Rosenheim | 35 | 179.5 |- | Feldkirchen | 38 | 204 |- | Wasserburg | 29 | 165.7 |- | Teufelsbruck | 25 | 150.4 |- | Gars | 30 | 169.2 |- | Jettenbach | 6 | 30.2 |- | Töging | 85 | 564.6 |- | Neuötting | 26 | 159.4 |- | Perach | 19 | 128.4 |- | Stammham | 23 | 136.4 |- | Braunau-Simbach | 100 | 550 |- | Ering-Frauenstein | 72 | 434 |- | Egglfing-Obernberg | 84 | 485 |- | Schärding-Neuhaus | 96 | 541.8 |- | Passau-Ingling | 86 | 504.7 |- |}

==See also== * List of rivers of Austria * List of rivers of Germany * List of rivers of Switzerland

==References== <references> <ref name="en1">{{cite web |title = Zentrale Ova Spin |publisher = Engadiner Kraftwerke |url = http://engadin-strom.ch/anlagen/zentrale-ova-spin.html |archive-url = https://web.archive.org/web/20160419115933/http://engadin-strom.ch/anlagen/zentrale-ova-spin.html |url-status = dead |archive-date = 19 April 2016 |language = de |access-date = 2016-01-18 }}</ref>

<ref name="en2">{{cite web |title = Zentrale Pradella |publisher = Engadiner Kraftwerke |url = http://ekwstrom.ch/anlagen/zentrale-pradella.html |language = de |access-date = 2016-01-18 |archive-date = 25 March 2016 |archive-url = https://web.archive.org/web/20160325202028/http://www.ekwstrom.ch/anlagen/zentrale-pradella.html |url-status = dead }}</ref>

<ref name="hnd">{{cite web | title = Statistik Passau Ingling / Inn | publisher = www.hnd.bayern.de | url = http://www.hnd.bayern.de/pegel/inn/passau-ingling-18008008/statistik? | language = de | access-date = 2016-04-05 }}</ref>

<ref name="in">{{cite web | title = Central Europe Hit by Rains, Floods and Landslides: AIR Analysis | publisher = www.insurancejournal.com | url = http://www.insurancejournal.com/news/international/2013/06/04/294260.htm | date = 2013-04-06 | access-date = 2016-04-05 }}</ref>

<ref name="st">{{cite web |title = Elektrizitäts-Produktion |publisher = www.stmoritz-energie.ch |url = http://www.stmoritz-energie.ch/ueber-uns/portrait/elektrizitaets-produktion.html |language = de |access-date = 2016-01-18 |archive-date = 2 December 2015 |archive-url = https://web.archive.org/web/20151202091822/http://www.stmoritz-energie.ch/ueber-uns/portrait/elektrizitaets-produktion.html |url-status = dead }}</ref>

<ref name="ti1">{{cite web | title = Kraftwerk Imst | publisher = Tiroler Wasserkraft | url = https://www.tiroler-wasserkraft.at/www_tiwag/de/hn/stromerzeugung/kraftwerkspark/imst/index.php | language = de | access-date = 2016-01-18 }}</ref>

<ref name="ti2">{{cite web | title = Kraftwerk Kirchbichl | publisher = Tiroler Wasserkraft | url = https://www.tiroler-wasserkraft.at/www_tiwag/de/hn/stromerzeugung/kraftwerkspark/kirchbichl/index.php | language = de | access-date = 2016-01-18 }}</ref>

<ref name="ti3">{{cite web | title = Kraftwerk Langkampfen | publisher = Tiroler Wasserkraft | url = https://www.tiroler-wasserkraft.at/www_tiwag/de/hn/stromerzeugung/kraftwerkspark/langkampfen/index.php | language = de | access-date = 2016-01-18 }}</ref>

<ref name="ve">{{cite web | title = VERBUND on the Inn | publisher = Verbund | url = http://www.verbund.com/pp/en/waters/inn | access-date = 2016-01-18 | archive-url = https://web.archive.org/web/20160306112158/http://www.verbund.com/pp/en/waters/inn | archive-date = 2016-03-06 | url-status = dead }}</ref> </references>

==External links== {{Commons category|Inn River}} * {{HDS|8089|Inn (district and river)|rm=250}}

{{Danube}}

{{Rivers of Germany}} {{Authority control}}

Category:Inn (river) Category:Rivers of Switzerland Category:Rivers of Bavaria Category:International rivers of Europe Category:Engadin Category:Celerina/Schlarigna Category:La Punt Chamues-ch Category:Madulain Category:S-chanf Category:Scuol Category:Sils im Engadin/Segl Category:Silvaplana Category:St. Moritz Category:Valsot Category:Zernez Category:Zuoz Category:Rivers of Tyrol (state) Category:Inn basin Category:Austria–Germany border Category:Rivers of the Grisons Category:Braided rivers in Europe Category:Rivers of Austria Category:Rivers of Germany