View source for Lake Constance

{{Short description|Lake in Germany, Switzerland and Austria}}
{{About|the European lake|other uses|Lake Constance (disambiguation)}}
{{Redirect|Bodensee|the municipality|Bodensee, Lower Saxony}}
{{Use dmy dates|date=April 2020}}
{{Infobox body of water
|native_name        ={{native name|de|Bodensee}}
|image              = Lake_Constance_Edited.png
|image_size         = 325px
|caption            = Satellite image
|image_bathymetry   = Karte Bodensee.png
|caption_bathymetry = Map
|location           = Germany, Switzerland, Austria
|coords             = {{coord|47|35|N|9|28|E|type:waterbody_scale:500000|display=inline,title}}
|type               = glacial lake
|part_of            = [[Rhine]]
|inflow             = [[Alpine Rhine]]
|outflow            = [[High Rhine]]
|catchment          = {{convert|11500|km2|sqmi|abbr=on}}<ref name=data/>
|basin_countries    = Germany, Switzerland, Austria<ref name=map500/><ref name=mapGPBW1>{{cite map |url=https://www.geoportal-bw.de/?appCtx=d9736810-1d92-11e8-8756-43a314516c63 |title=Bodensee |map=WMS LGL-BW ATKIS Digitale Topographische Karte 1:50 000 Farbkombination |scale=1:50 000 |date=2017-12-20 |publisher=Landesamt für Geoinformation und Landentwicklung Baden-Württemberg |location=Stuttgart, Germany |via=www.geoportal-bw.de Geoportal Baden-Württemberg |access-date=2018-03-01}}</ref>
|length             = {{convert|63|km|mi|abbr=on}}<ref name=data/>
|width              = {{convert|14|km|mi|abbr=on}}<ref name=data/>
|area               = {{convert|536|km2|sqmi|abbr=on}}<ref name=data/>
|depth              = {{convert|90|m|ft|abbr=on}}
|max-depth          = {{convert|251|m|ft|abbr=on}}<ref name=data/>
|volume             = {{convert|48|km3|cumi acre.ft|sigfig=2|abbr=on}}<ref name=data/>
|residence_time     = 4.3 years
|shore              = {{convert|273|km|mi|abbr=on}}<ref name=data/>
|elevation          = {{convert|395|m|ft|abbr=on}}
|frozen             = 1795, 1830, 1880 (partial), 1963
|islands            = {{ulist|[[Mainau]]|[[Island of Reichenau|Reichenau]]|[[Lindau (island)|Lindau]]|''and others''}}
|cities             = see [[#settlements|list]]
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| website            = 
|sections           = {{ulist|[[Obersee (Lake Constance)|Obersee]]{{ulist|[[Lake Überlingen|Überlinger See]]}}|[[Seerhein]]|[[Untersee (Lake Constance)|Untersee]]{{ulist|[[Gnadensee]]{{ulist|[[Markelfinger Winkel]]}}|[[Zeller See (Lake Constance)|Zeller See]]|[[Rheinsee]]}}}}
|reference          =<ref name=data/><ref name=map500/><ref name=mapGPBW1/><ref name=map28/><ref name=map28bis/>
| pushpin_map=Alps#Canton of St. Gallen#Switzerland#Germany Baden-Württemberg#Germany#Austria Vorarlberg#Austria
| pushpin_label_position= right
| mapframe = yes
| mapframe-zoom = 9
}}
'''Lake Constance''' ({{langx|de|'''Bodensee'''}}, {{IPA|de|ˈboːdn̩zeː|pron|De-Bodensee2.ogg}}) refers to three [[Body of water|bodies of water]] on the [[Rhine]] at the northern foot of the [[Alps]]: [[Upper Lake Constance]] (''Obersee''), [[Lower Lake Constance]] (''Untersee''), and a connecting stretch of the Rhine, called the [[Seerhein]] ({{lit|Rhine of the lake(s)}}). These waterbodies lie within the Lake Constance Basin ({{lang|de|Bodenseebecken}}) in the [[Alpine Foreland]] through which the [[Rhine]] flows.<ref name=map500>{{cite map |url=https://s.geo.admin.ch/790d045b60 |title=Bodensee |map=Schweiz Suisse Svizzera Svizra |map-url=https://shop.swisstopo.admin.ch/en/products/maps/national/lk500?layer=ch.swisstopo.landeskarte500_papier.metadata&product=LK500000&productIdentifier=LK500000#product-LK500000 |scale=1:500 000 |series=National Map 1:500'000 |edition=2014 |publisher=Federal Office of Topography – [[swisstopo]] |location=Wabern, Switzerland |isbn=978-3-302-00070-1 |via=map.geo.admin.ch |access-date=2018-02-28}}</ref><ref name=mapGPBW1/> The nearby ''[[Mindelsee]]'' is not considered part of Lake Constance.
The lake is situated where [[Germany]], [[Switzerland]], and [[Austria]] meet. Its shorelines lie in the German states of [[Baden-Württemberg]] and [[Bavaria]]; the [[Cantons of Switzerland|Swiss cantons]] of [[Canton of St. Gallen|St. Gallen]], [[Canton of Thurgau|Thurgau]], and [[Canton of Schaffhausen|Schaffhausen]]; and the Austrian state of [[Vorarlberg]]. The actual locations of the country borders within the lake are disputed, with Austria, Germany and Switzerland all holding different opinions on the matter.

The [[Alpine Rhine]] forms, in its original course ([[Alter Rhein]]), the [[Austria–Switzerland border|Austro-Swiss border]] and flows into the lake from the south. The [[High Rhine]] flows westbound out of the lake and forms (with the exception of the [[Canton of Schaffhausen#Geography|Canton of Schaffhausen]], [[Rafzerfeld]] and [[canton of Basel-Stadt|Basel-Stadt]]) the [[Germany–Switzerland border|German-Swiss border]] as far as to the city of [[Basel]].<ref name=map28>{{cite map |url=https://s.geo.admin.ch/790d045b60 |title=Bodensee |map=28 – Bodensee |map-url=https://shop.swisstopo.admin.ch/en/products/maps/national/lk100?layer=ch.swisstopo.landeskarte100_papier.metadata&product=28&productIdentifier=28&childGroupIdentifier=lk100eb#product-28 |scale=1:100 000 |series=National Map 1:100'000 |edition=2010 |date=2008 |publisher=Federal Office of Topography – [[swisstopo]] |location=Wabern, Switzerland |isbn=978-3-302-00028-2 |via=map.geo.admin.ch |access-date=2018-02-28}}</ref><ref name=map28bis>{{cite map |url=https://s.geo.admin.ch/790d4eab9d |title=Lindau |map=28bis - Lindau |map-url=https://shop.swisstopo.admin.ch/en/products/maps/national/lk100?layer=ch.swisstopo.landeskarte100_papier.metadata&product=28bis&productIdentifier=28bis&childGroupIdentifier=lk100eb#product-28bis |scale=1:100 000 |series=National Map 1:100'000 |edition=2010 |date=2008 |publisher=Federal Office of Topography – [[swisstopo]] |location=Wabern, Switzerland |isbn=978-3-302-10028-9 |via=map.geo.admin.ch |access-date=2018-02-28}}</ref> The [[Leiblach]] forms the [[Austria–Germany border]] east of the lake.

The most populous towns on the Upper Lake are [[Konstanz|Constance]] ({{langx|de|Konstanz}}), [[Friedrichshafen]], [[Bregenz]], [[Lindau]], [[Überlingen]] and [[Kreuzlingen]]. The largest town on the Lower Lake is [[Radolfzell]]. The largest islands are [[Reichenau Island|Reichenau]] in the Lower Lake, and [[Lindau (island)|Lindau]] and [[Mainau]] in the Upper Lake. [[Bodanrück]], a large peninsula, separates the Upper and Lower Lake.

While in English and in the [[Romance languages]], the lake is named after the city of [[Konstanz|Constance]], the German name derives from the village of Bodman (municipality of [[Bodman-Ludwigshafen]]), in the northwesternmost corner of the lake.

==Description==
Lake Constance is located along the [[Rhine]] between the [[Alpine Rhine]], its main [[tributary]], and the [[High Rhine]], its outflow. It is the [[List of largest lakes of Europe|third largest]] freshwater lake by surface area in Central and Western Europe (and the second largest in volume), after [[Lake Geneva]] and (in surface area) [[Lake Balaton]].

It is {{convert|63|km|abbr=on}} long, and, nearly {{convert|14|km|abbr=on}} at its widest point. It covers about {{convert|536|km2|abbr=on}}, and is {{convert|395|m|abbr=on}} above [[sea level]]. Its greatest depth is {{convert|252|m}}, exactly in the middle of the Upper Lake. Its volume is about {{convert|48|km3|abbr=on}}.<ref name=data>{{cite web |url=https://www.igkb.org/der-bodensee/seedaten/ |title=Bodensee-Daten |publisher=igkb Internationale Gewässerschutzkommission für den Bodensee |date=June 2004 |language=de |access-date=2018-02-28 |archive-date=1 March 2018 |archive-url=https://web.archive.org/web/20180301104135/https://www.igkb.org/der-bodensee/seedaten/ |url-status=dead }}</ref>

The lake has two parts. The main east section, called [[Obersee (Lake Constance)|Obersee]] or "Upper Lake", covers about {{convert|473|km2}}, including its northwestern arm, the [[Überlinger See]] ({{convert|61|km2|abbr=on}}), and the smaller west section, called [[Untersee (Lake Constance)|Untersee]] or "Lower Lake", with an area of about {{convert|63|km2}}.<ref name=data/><ref name=mapGPBW1/>

The connection between these two lakes is the [[Seerhein]] (lit.: "Rhine of the Lake(s)"). Geographically, usually it is not considered to be part of the lake, but a very short river.<ref name=data/><ref name=map28/>

The Lower Lake Constance is loosely divided into three sections around the [[Island of Reichenau]]. The two German parts, the [[Gnadensee]] (lit.: "Lake Mercy") north of the island and north of the peninsula of Mettnau (the [[Markelfinger Winkel]]), and the [[Zeller See (Lake Constance)|Zeller See]], south of Radolfzell and to the northwest of the Reichenau island, and the mainly Swiss [[Rheinsee]] (lit.: "Lake Rhine") – not to be mistaken for the ''Seerhein'' (lit.: "Rhine of the Lake(s)") at its start – to the south of the island and with its southwestern arm leading to its effluent in [[Stein am Rhein]].<ref name=data/><ref name=mapGPBW1/>

The water of the [[Rhine Regulation|regulated]] Alpine Rhine flows into the lake in the southeast near [[Bregenz]], Austria, then through the Upper Lake Constance hardly targeting the ''Überlinger See'', into the ''Seerhein'' in the town of [[Konstanz]], then through the ''Rheinsee'' virtually without feeding both German parts of the Lower Lake, and finally feeds the start of the [[High Rhine]] in Swiss town [[Stein am Rhein]].<ref name=data/><ref name=map28bis/><ref name=mapGPBW1/>

The lake itself is an important source of drinking water for southwestern Germany.

The culminating point of the lake's drainage basin is the Swiss peak [[Piz Russein]] of the Tödi massif of the [[Glarus Alps]] at {{convert|3613|m}} above sea level. It starts with the creek ''Aua da Russein'' (lit.: "Water of the Russein").<ref>{{cite map |url=http://s.geo.admin.ch/9324aa0f5 |title=Piz Russein |map=1193 – Tödi |map-url=https://shop.swisstopo.admin.ch/en/products/maps/national/lk25?layer=ch.swisstopo.landeskarte25_papier.metadata&product=1193&productIdentifier=1193&childGroupIdentifier=lk25eb#product-1193 |scale=1:25 000 |series=National Map 1:25'000 |edition=2016 |date=2013 |publisher=Federal Office of Topography – [[swisstopo]] |location=Wabern, Switzerland |isbn=978-3-302-01193-6 |via=map.geo.admin.ch |access-date=2018-02-28}}</ref>

==History==
Lake Constance was formed by the [[Rhine Glacier]] during the [[Quaternary glaciation]] ice age and is a ''[[Zungenbecken]]'' or Tongue lake. After the end of the [[Würm glaciation|last glacial period]], about 10,000 years ago, the Obersee and Untersee still formed a single lake. The [[downward erosion]] of the [[High Rhine]] caused the lake level to gradually sink and a sill, the ''Konstanzer Schwelle'', to emerge.

The Rhine, the [[Bregenzer Ach]], and the [[Dornbirner Ach]] carry sediments from the [[Alps]] to the lake, thus gradually decreasing the depth and reducing the extension of the lake in the southeast.

In antiquity, the two lakes had different names; later, for reasons which are unknown, they came to have the same name.

In the 19th century, there were five different local [[time zone]]s around Lake Constance. Constance, belonging to the [[Grand Duchy of Baden]], adhered to [[Karlsruhe]] time, Friedrichshafen used the time of the [[Duchy of Württemberg]], in Lindau, the Bavarian Munich time was observed, and Bregenz used Prague time, while the Swiss shore used Berne time. One would have needed to travel only {{convert|46|km}} to visit five time zones. Given the amount of trade and traffic over Lake Constance, this led to serious confusion. Public clocks in harbors used three different clock faces, depending on the destinations offered by the boat companies. In 1892, all German territories used [[Central European Time|CET]], the Austrian railways had already introduced CET the previous year and Switzerland followed in 1894. Because traffic timetables had not been yet updated, CET became the sole valid time around and on Lake Constance in 1895.<ref>[[:de:Fünf Ortszeiten am Bodensee|"Fünf Ortszeiten am Bodensee"]] in the German Wikipedia, version used 2018-01-08.</ref>

=== Name ===
The earliest recorded reference to the lakes is by [[Roman Empire|Roman]] geographer [[Pomponius Mela]] around AD&nbsp;43, calling the upper lake ''Lacus Venetus'' and the lower lake ''Lacus Acronius'', the Rhine passing through both. Around AD&nbsp;75, the naturalist [[Pliny the Elder]] called them both ''Lacus Raetiae Brigantinus'' after the main Roman town on the lake, ''[[Bregenz|Brigantium]]'' (later Bregenz). This name is associated with the [[Celts|Celtic]] [[Brigantii]] who lived here, although it is not clear whether the place was named after the tribe or the inhabitants of the region were named after their main settlement. [[Ammianus Marcellinus]] later used the form ''Lacus Brigantiae''.<ref name=Reitzenstein>{{cite book |editor=Wolf-Armin Freiherr von Reitzenstein |title=Lexikon schwäbischer Ortsnamen. Herkunft und Bedeutung. |publisher=[[Verlag C. H. Beck]] |location=Munich, Germany |date=2013 |isbn=978-3-406-65209-7 |page=68 |language=de |url={{Google books|EY6iAAAAQBAJ|page=68|plainurl=yes}}}}</ref>

The current German name of ''Bodensee'' derives from the place name [[Bodman-Ludwigshafen|Bodman]], which probably originally derived from the [[Old High German]] ''bodamon'' which meant "on the soils", indicating a place on level terrain by the lake.<ref name=AB>{{cite journal |author=Arno Borst |title=Bodensee – Geschichte eines Wortes |journal=Schriften des Vereins für Geschichte des Bodenseeraums |volume=99, 100 |date=1982 |issue=Heft 1981/1982 |language=de |publisher=Selbstverlag des Bodenseegeschichtsvereins |location=Friedrichshafen}}</ref>{{rp|500}} This place, situated at the west end of Lake Überlingen (''Überlinger See''), had a more supraregional character for a certain period in the [[early Middle Ages]] as a [[Franks|Frankish]] [[Kaiserpfalz|imperial palace]] (''Königspfalz''), [[Alamanni]]an ducal seat and [[mint (facility)|mint]], which is why the name may have been transferred to the lake ("lake, by which Bodman is situated" = ''Bodmansee''). From 833 or 834, in Latin sources, the name appears in its [[Latinization (historical)|Latinised]] form ''lacus potamicus''.<ref>{{cite book |author=Rolf Zimmermann |title=Am Bodensee |publisher=Stadler Verlagsgesellschaft |location=Konstanz, Germany |date=2004 |isbn=3-7977-0504-2 |page=5 |language=de}}</ref> Therefore, the name actually derived from the Bodman ''Pfalz'' (Latinized as ''Potamum'') was wrongly assumed by monastic scholars like [[Walahfrid Strabo]] to be derived from the Greek word ''potamos'' for "river" and meant "river lake". They may also have been influenced by the fact that the Rhine flowed through the lake.<ref name=AB/>{{rp|501ff}}

[[Wolfram von Eschenbach]] describes it in [[Middle High German]] as the ''Bodemensee'' or ''Bodemsee''<ref>{{cite book |author=Wilhelm Martens |title=Geschichte der Stadt Konstanz |publisher=Gess |location=Konstanz, Germany |pages=6–7 |date=1911 |language=de}}</ref> which has finally evolved into the present German name, ''Bodensee''. The name may be linked to that of the [[Bodanrück]], the hill range between Lake Überlingen and the Lower Lake, and the history of the [[House of Bodman]].

[[File:Alamannien Hochburgund ca 1000.png|thumb|upright=1.5|Location of Lake Constance within the Duchy of Swabia (yellow), 911–1268]]

The German name of the lake, ''Bodensee'', has been adopted by many other languages, for example: Dutch: ''Bodenmeer'', Danish: ''Bodensøen'', Norwegian: ''Bodensjøen'', Swedish: ''Bodensjön'', Finnish: ''Bodenjärvi'', Russian: ''Боденское озеро'', Polish: ''Jezioro Bodeńskie'', Czech: ''Bodamské jezero'', Slovak: ''Bodamské jazero'', Hungarian: ''Bodeni-tó'', Serbo-Croatian: ''Bodensko jezero'', Albanian: ''Liqeni i Bodenit''.

After the [[Council of Constance]] in the 15th century, the alternative name ''Lacus Constantinus'' was used in the (Roman Catholic) Romance language area. This name, which had been attested as early as 1187 in the form ''Lacus Constantiensis'',<ref name=Reitzenstein/> came from the town of Konstanz at the outflow of the Rhine from the Obersee, whose original name, Constantia, was in turn derived from the Roman emperor, [[Constantius Chlorus]] (around 300 AD). Hence the French: ''Lac de Constance'', Italian: ''Lago di Costanza'', Portuguese: ''Lago de Constança'', Spanish: ''Lago de Constanza'', Romanian: ''Lacul Constanța'', Greek: ''Λίμνη της Κωνσταντίας – Limni tis Konstantias''. The Arabic, بحيرة كونستانس ''buħaira Konstans'' and the Turkish, ''Konstanz gölü'', probably go back to the French form of the name. Even in Romance-influenced English the name "Lake Constance" gained a foothold and was then exported into other languages such as Hebrew: ימת קונסטנץ ''yamat Konstanz'' and Swahili: ''Ziwa la Konstanz''. In many languages both forms exist in parallel e.g. [[Romansch language|Romansh]]: ''Lai da Constanza'' and ''Lai Bodan'', Esperanto: ''Konstanca Lago'' and ''Bodenlago''.{{citation needed|date=March 2018}}

The poetic name, "[[Swabia]]n Sea", was adopted by authors of the [[early modern era]] and the [[Age of Enlightenment|Enlightenment]] from ancient authors, possibly [[Tacitus]]. However, this assumption was based on an error (similar to that of the [[Teutoburg Forest]] and the [[Taunus]]): the Romans sometimes used the name ''Mare Suebicum'' for the [[Baltic Sea]], not Lake Constance. In times when the Romans had located the so-called "[[Suebi]]", then an [[Elbe Germanic tribe]] near a sea, this was understandable. The authors of the [[Early Modern Period]] overlooked this and adopted the name for the largest lake in the middle of the former [[Duchy of Swabia]], which also included parts of today's Switzerland.<ref>{{cite journal |author=Karl Heinz Burmeister |title=Der Bodensee im 16. Jahrhundert |journal=Montfort, Vierteljahreszeitschrift für Geschichte und Gegenwart Vorarlbergs |publisher=Vorarlberger Verlagsanstalt |location=Dornbirn, Austria |volume=57 |date=2005 |issue=Heft 3 |pages=228–262 |url=http://www.vorarlberg.gv.at/pdf/m053burmeisterbodensee.pdf |language=de |via=vorarlberg.gv.at |access-date=2018-03-01 |archive-url=https://web.archive.org/web/20120131092421/http://www.vorarlberg.gv.at/pdf/m053burmeisterbodensee.pdf |archive-date=31 January 2012 |url-status=dead }}</ref> Today the name Swabian Sea (''Schwäbisches Meer'') is only used jocularly as a hyperbolic term for Lake Constance.<ref>{{cite news |author=Klaus Zintz |url=http://www.seezeichen-bodensee.de/files/media/cdn.php?params=%7B%22id%22%3A%22MDB-723c6b68-c469-4906-9424-0df9998ce220-MDB%22%2C%22type%22%3A%22download%22%2C%22date%22%3A%221453829719%22%7D&Stuttgarter-Zeitung_07.08.2015.pdf |title=Der Bodensee lädt nicht nur zum Baden ein. |newspaper=[[Stuttgarter Zeitung]] |location=Stuttgart, Germany |date=7 August 2015 |language=de |via=www.seezeichen-bodensee.de |access-date=2018-03-01 |archive-url=https://web.archive.org/web/20161009124006/http://www.seezeichen-bodensee.de/files/media/cdn.php?params=%7B%22id%22:%22MDB-723c6b68-c469-4906-9424-0df9998ce220-MDB%22,%22type%22:%22download%22,%22date%22:%221453829719%22%7D&Stuttgarter-Zeitung_07.08.2015.pdf |archive-date=2016-10-09 |url-status=dead }}</ref>

=== Key facts ===
[[File:Columban und Gallus auf dem Bodensee.jpg|thumb|Saints [[Columbanus]] and [[Saint Gall|Gallus]] on Lake Constance, from a 15th-century manuscript]]
No [[Paleolithic]] finds have been made in the immediate vicinity of the lake, because the region of Lake Constance was long covered by the [[Rhine Glacier]]. The discovery of stone tools ([[microlith]]s) indicate that [[hunters and gatherers]] of the [[Mesolithic]] period (Middle Stone Age, 8,000–5,500 BC) frequented the area without settling, however. Only hunting camps have been confirmed. The earliest Neolithic farmers, who belonged to the [[Linear Pottery culture]], also left no traces behind, because the Alpine foreland lay away from the routes along which they had spread during the 6th millennium BC.<ref>{{cite magazine |author=Helmut Schlichtherle |title=Pfahlbauten: die frühe Besiedelung des Alpenvorlandes |magazine=Spektrum der Wissenschaft |volume=1989 |issue=Siedlungen der Steinzeit |publisher=Spektrum-Verlag |location=Heidelberg, Germany |date=1989 |isbn=3-922508-48-0 |pages=140 ff |language=de}}</ref> This changed only in the middle and late [[Neolithic]] when shore settlements were established, the so-called [[pile dwelling]] and [[wetland settlement]]s, which have now been uncovered mainly on Lake Überlingen, the [[Constance Hopper]] and on the Obersee. At [[Unteruhldingen]], a pile dwelling village has been reconstructed, and now forms an open air museum.
In 2015, a 20&nbsp;km line of about 170 man-made {{ill|Stone mounds in Lake Constance|de|Steinhügel im Bodensee|lt=under-water stone mounds}} dated in the Neolithic period or early Bronze Age was discovered on the south-west shore of the lake between Bottighofen and Romanshorn.<ref name="Leuzinger_2018">{{cite web |title=Rätselhafte Steinstrukturen im Bodensee |language=de-CH |date=2018 |editor-first=Urs |editor-last=Leuzinger |publisher=Amt für Archäologie |location=Thurgau, Switzerland |url=https://archaeologie.tg.ch/public/upload/assets/65113/2018_Medienmitteilung_H%3Fgeli_Uttwil.pdf |access-date=2022-07-27 |url-status=live |archive-url=https://web.archive.org/web/20220401010814/https://archaeologie.tg.ch/public/upload/assets/65113/2018_Medienmitteilung_H%3Fgeli_Uttwil.pdf |archive-date=2022-04-01}} (3 pages)</ref><ref name="Schaer_2019">{{cite magazine |title=Bohren nach dem Rätsel |language=de-CH |date=2019-06-11 |author-first=Markus |author-last=Schär |magazine=thurgaukultur.ch |department=Wissen |url=https://www.thurgaukultur.ch/magazin/bohren-nach-dem-raetsel-4050 |access-date=2022-07-27 |url-status=live |archive-url=https://web.archive.org/web/20190621150024/https://www.thurgaukultur.ch/magazin/bohren-nach-dem-raetsel-4050 |archive-date=2019-06-21}}</ref><ref name="NZZ_2019">{{cite news |title=Die rätselhaften Steinhügel im Bodensee stammen vermutlich aus der Bronzezeit |language=de-CH |newspaper=[[Neue Zürcher Zeitung]] |department=Wissenschaft |date=2019-06-07 |url=https://www.nzz.ch/wissenschaft/raetselhafte-steinhuegel-im-bodensee-bohrproben-entnommen-ld.1487604 |access-date=2022-07-27 |url-status=live |archive-url=https://web.archive.org/web/20220727180229/https://www.nzz.ch/wissenschaft/raetselhafte-steinhuegel-im-bodensee-bohrproben-entnommen-ld.1487604?reduced=true |archive-date=2022-07-27}}</ref><ref name="Meile_2018">{{cite web |title=Steinhügel im Bodensee: Was haben sich die Pfahlbauer bloss dabei gedacht? |language=de-CH |date=2018-11-25 |author-first=Silvan |author-last=Meile |work=Tagblatt |url=https://www.tagblatt.ch/ostschweiz/frauenfeld/gruebeln-unter-wasser-was-haben-sich-die-pfahlbauer-dabei-bloss-gedacht-ld.1072604 |access-date=2022-07-27 |url-status=live |archive-url=https://web.archive.org/web/20210613214928/https://www.tagblatt.ch/ostschweiz/frauenfeld/gruebeln-unter-wasser-was-haben-sich-die-pfahlbauer-dabei-bloss-gedacht-ld.1072604 |archive-date=2021-06-13}}</ref><ref name="SRF_2019">{{cite web |title=Mysteriöse Steinhügel im Bodensee |language=de-CH |date=2019-09-27 |work=SRF News |url=https://www.srf.ch/wissen/natur-tiere/raetsel-geloest-bodensee-stonehenge-stammt-aus-der-jungsteinzeit |access-date=2022-07-27 |url-status=live |archive-url=https://web.archive.org/web/20220727180513/https://www.srf.ch/wissen/natur-tiere/raetsel-geloest-bodensee-stonehenge-stammt-aus-der-jungsteinzeit |archive-date=2022-07-27}} [0:49]</ref>

Grave finds from [[Singen am Hohentwiel]] date to the beginning of the Early [[Bronze Age]] and shore settlements were repeatedly built during the [[Neolithic Period]] and the Bronze Age (up to 800 BC). During the following [[Iron Age]] the settlement history is interrupted. The settlement of the shore of Lake Constance during the [[Hallstatt period]] is attested by [[grave mounds]], which today are usually found in forests where they have been protected from the destruction by agriculture. Since the late Hallstatt period, the peoples living on Lake Constance are referred to as the [[Celts]]. During the [[La Tène period]] from 450 BC, the population density decreases, as can be deduced partly due from the fact that no more grave mounds were built. For the first time, written reports on Lake Constance have survived. Thus, we learn that the [[Helvetians]] settled by the lake in the south, the [[Rhaetians]] in the area of the [[Alpine Rhine Valley]] and the [[Vindelici]] in the north-east. The most important places on the lake were [[Bregenz]] (Celtic ''Brigantion'') and today's [[Konstanz|Constance]].

In the course of the Roman [[Augustine Alpine Campaign|Alpine campaign]] of 16/15 BC, the Lake Constance region was integrated into the [[Roman Empire]]. During the campaign, there was also supposed to have been a [[Battle of Lake Constance|battle on Lake Constance]]. The geographer, [[Pomponius Mela]], makes the first mention in 43 AD of Lake Constance as two lakes – the ''Lacus Venetus'' (Upper Lake) and the ''Lacus Acronius'' (Untersee) – with the Rhine flowing through both. [[Pliny the Elder]] referred to Lake Constance as ''Lacus Brigantinus'' for the first time. The most important Roman site was Bregenz, which soon became subject to Roman municipal law and later became the seat of the Prefect of the Lake Constance fleet. The Romans were also in [[Lindau (Lake Constance)|Lindau]], but settled only on the hills around Lindau as the lakeshore was swampy. Other Roman towns were ''Constantia'' (Constance) and ''Arbor Felix'' ([[Arbon]]).

After the borders of the Roman Empire were drawn back to the Rhine boundary in the 3rd century BC, the Alemanni gradually settled on the north shore of Lake Constance and, later, on the south bank as well. After the introduction of [[Christianity]], the cultural significance of the region grew as a result of the founding of [[Reichenau Abbey]] and the [[Diocese of Constance|Bishopric of Constance]]. Under the rule of the [[Hohenstaufen]]s, [[Imperial Diet (Holy Roman Empire)|Imperial Diets]] (''Reichstage'') were held by Lake Constance. In Constance, too, a treaty was drawn up between the Hohenstaufen emperor and the [[Lombard League]]. Lake Constance also played an important role as a trading post for goods being traded between German and Italian states.

During the [[Thirty Years' War]], there were various conflicts over the control of the region during the [[Lake War]] (1632–1648).

After the [[War of the Second Coalition]] (1798–1802), which also affected the region and during which Austrian and French [[flotilla]]s operated on Lake Constance, there was a reorganisation of state relationships.

=== Historical maps ===
[[File:Lacus Constantiensis 1540.jpg|thumb|1540 map of the Lake Constance region]]
* 1540: the map ''Lacus Constantiensis'' by [[Johannes Zwick]] and [[Thomas Blarer]] shows topographic names, towns and the Rhine.{{citation needed|date=March 2018}}
* 1555: the map of the route of the Rhine (''Rhinelaufkarte'') by [[Caspar Vopel]] includes a topographical map of Lake Constance with its larger towns, the tributaries and the course of the Rhine.{{citation needed|date=March 2018}}
* 1633: the Swabian map by [[Johannes Janssonius]], Amsterdam: ''Totius Sveviae novissima tabula'' shows Lake Constance with islands, tributaries, towns and villages.<ref>{{Citation |author=Rolf Zimmermann |title=Am Bodensee |language=de |location=Constance |date=2004 |page=endpaper and 112}}</ref>
* 1675: The Lake Constance map, ''Lacos Acronianus sive Bodamicus'', by Nikolaus David Hautt based on Andreas Arzet [[Jesuits|SJ]] shows Lake Constance with the adjacent lands.<ref>{{Citation |url=https://aleph.unibas.ch/F/?local_base=DSV01&con_lng=ENG&func=find-b&find_code=SYS&request=001066422 |title=Der Bodensee (Latin: ''Lacvs Acronianvs siue Bodamicvs'') |type=copper print 38 x 51 cm |publisher=University of Berne |date=1970 |orig-year=1675 |location=Berne, Switzerland}}</ref>

== Geography ==
[[File:Lake Constance from Winterstaude (East to West).JPG|thumb|Complete lake from the [[Winterstaude]]]]

=== Divisions ===
Lake Constance is located in the foothills of the [[Alps]]. The shore length of both main lakes is {{convert|273|km|mi}} long. Of this, {{convert|173|km|mi}} are located in Germany ([[Baden-Württemberg]] {{convert|155|km|mi|disp=or}}, [[Bavaria]] {{convert|18|km|mi|disp=or}}), {{convert|28|km|mi}} run through Austria and {{convert|72|km|mi}} through Switzerland.<ref>''Bodensee-Daten.'' In: Internationale Gewässerschutzkommission für den Bodensee (publ.): ''Seespiegel.'' December 2011, p. 6.</ref> If the upper and lower lakes are combined, Lake Constance has a total area of {{convert|536|km2|sqmi|abbr=on}}, the third largest lake in [[Central Europe]] by area after [[Lake Balaton]] ({{convert|594|km2|sqmi|abbr=on|disp=or}}) and [[Lake Geneva]] ({{convert|580|km2|sqmi|abbr=on|disp=or}}). It is also the second largest by water volume ({{convert|48.5|km3|cumi acre.ft|lk=out|abbr=on|disp=or}})<ref name="Gewässerschutzkommission">Uta Mürle, Johannes Ortlepp, Peter Rey, Internationale Gewässerschutzkommission für den Bodensee (publ.): ''Der Bodensee: Zustand – Fakten – Perspektiven.'' 2nd revised edition. Bregenz, 2004, {{ISBN|3-902290-04-8}}, p.&nbsp;10.</ref> after Lake Geneva ({{convert|89|km3|cumi acre.ft|abbr=on|disp=or}}) and extends for over {{convert|69.2|km|mi}} between [[Bregenz]] and [[Stein am Rhein]]. Its [[drainage basin|catchment area]] is around {{convert|11500|km2|sqmi|abbr=on}}, and reaching as far south as [[Lago di Lei]] in Italy.<ref>[http://www.hydra-institute.com/igkb/IGKB%201.2.pdf www.hydra-institute.com] {{webarchive|url=https://web.archive.org/web/20120514054950/http://www.hydra-institute.com/igkb/IGKB%201.2.pdf |date=2012-05-14 }} (pdf; 1.2&nbsp;MB)</ref>

The area of the [[Obersee (Lake Constance)|Obersee]], or Upper Lake, is {{convert|473|km2|sqmi|abbr=on}}. It extends from Bregenz to [[Bodman-Ludwigshafen]] for over {{convert|63.3|km|mi}} and is {{convert|14|km|mi}} wide between [[Friedrichshafen]] and [[Romanshorn]]. At its deepest point between [[Fischbach (Friedrichshafen)|Fischbach]] and [[Uttwil]], it is {{convert|251.14|m|ft}} deep.

[[File:Bodensee vom Pfänder (Aurtia).JPG|thumb|Lake Constance with the Island of Lindau seen from the [[Pfänder]] in 2007]]
The three small bays on the [[Vorarlberg]] shore have their own names: the Bay of Bregenz, off [[Hard, Austria|Hard]] and [[Fußach]] is the Bay of Fussach and, west of that is the Wetterwinkel. Farther west, now in Switzerland, is the Bay of Rorschach. To the north, on the Bavarian side, is the Bay of Reutin. The railway embankment from the mainland to the island of Lindau and the motorway bridge over the lake border the so-called Little Lake (''Kleiner See''), which is located between the Lindau village of Aeschach and the island.

The northwestern, finger-shaped arm of the Obersee is called Überlinger See (or Überlingersee in [[Swiss Standard German]]), or [[Lake Überlingen]]. It is sometimes regarded as a separate lake, the boundary between Lake Überlingen and the rest of the Upper Lake runs approximately along the line between the southeast tip of Bodanrück (the ''Hörnle'', which belongs to the town of Konstanz) and Meersburg. The [[Constance Hopper]] lies between the German and Swiss shores east of [[Konstanz]].

The Obersee and Untersee are connected by the [[Seerhein]].

The [[Untersee (Lake Constance)|Untersee]], or Lower Lake, which is separated from the Obersee and from its north-west arm, the Überlinger See, by the large peninsula of [[Bodanrück]], has an area of {{convert|63|km2|sqmi|abbr=on}}. It is strongly characterised and divided into different areas by [[end moraine]]s, various [[glacial snout]]s and [[medial moraine]]s. These various areas of the lake have their own names. North of [[Reichenau Island]] is the [[Gnadensee]]. West of the island of Reichenau, between the peninsula of [[Höri (Lake Constance)|Höri]] and the peninsula of [[Mettnau]] is the Zeller See (or Zellersee in Swiss Standard German), or [[Lake Zell]]. North of the peninsula and swamp land Mettnau lies the lake part Markelfinger Winkel. The [[drumlin]]s of the southern Bodanrück continue along the bed of these northern parts of the lake. South of the Reichenau, from [[Gottlieben]] to [[Eschenz]], stretches the ''Rheinsee'' (lit.: "Rhine Lake") with strong Rhine currents in places. Previously this lake part was named Lake Bernang after the village of [[Berlingen, Switzerland|Berlingen]]. On most of the maps the name of the ''Rheinsee'' is not shown, because this place is best suited for the name of the Untersee.<ref name="Seespiegel_20">[http://www.seespiegel.de/html/archiv/Artikel/Nummer20/1204_002.htm ''Der Bodensee: drei Teile, ein See.''] In: ''Seespiegel.'' Edition 20.</ref>

{{multiple image|perrow = 3|total_width=900
|align=center
|header = Lake Constance on the Swiss National Map (1:50'000)
|image1=206 Stein am Rhein.jpg
|image2=207 Konstanz.jpg
|image3=14000by9600white.svg<!--left blank-->
|image4=216 Frauenfeld.jpg
|image5=217 Arbon.jpg
|image6=218 Bregenz.jpg
|footer = 
}}

=== Emergence and future ===
The present-day shape of Lake Constance has resulted from the combination of several factors:
* The [[tectonic]] Lake Constance Basin between the Alps and the Jura was created in the [[Jurassic]] and [[Tertiary (period)|Tertiary]] periods.
* The current [[Alpine Rhine]] was initially a tributary of the Danube.
* Over time, the basin was [[stream capture|captured]] by the [[High Rhine]] as a result of [[headward erosion]] ([[fluvial erosion]]).
** The capture was not always only along the present Rhine valley; [[Lake Überlingen]] marks part of an older valley course.
* The river valleys were deepened during several [[cold period]]s by the [[Rhine Glacier]] from the valley of the Alpine Rhine ([[glacial erosion]]).
* Behind the present impressive traces of the [[Würm Ice Age]], the effects of older cold periods can no longer be explored in any detail. Lake Constance now represents, above all, a [[zungenbecken]] or [[glacial lake]] of the Würm Glaciation.<ref>quaternary-science.publiss.net/articles/452/download Albert Schreiner: ''Zur Entstehung des Bodenseebeckens'' (Quaternary Science Journal, pdf)</ref>
* During a later phase of the ice age, only the Obersee was glaciated. As the glacier retreated further, the [[glacial meltwater]]s flowed out of the emerging Überlingen See through the older more northerly valley into the present High Rhine valley.
* Due to the advancing headward erosion, the present course of the High Rhine was finally (again) reconnected to Lake Constance.<ref>[http://www.landeskunde-online.de/rhein/bodensee/geologie.htm Geology of Lake Constance] at landeskunde-online.de. Retrieved 31 August 2017.</ref> <!-- It is questionable whether there has ever been an undivided Lake Constance -->

Like any glacial lake, Lake Constance will also silt up by [[sedimentation]]. This process can best be observed at the mouths of the larger rivers, especially that of the Alpine Rhine. The [[silting up]] process is accelerated by ever-increasing erosion by the Rhine and the associated reduction in the level of the lake.

=== Tributaries ===
[[File:Aerial image of the mouth of the Rhine into Lake Constance.jpg|thumb|The mouth of the Alpine Rhine into Lake Constance]]
The main tributary of Lake Constance is the [[Alpine Rhine]]. The Alpine Rhine and the [[Seerhein]] do not mix greatly with the waters of the lake and flow through the lakes along courses that change relatively little. There are also numerous smaller tributaries (236 in all). The most important tributaries of the Obersee are (counterclockwise) the [[Dornbirner Ach]], [[Bregenzer Ach]], [[Leiblach]], [[Argen]], [[Schussen]], [[Rotach (Lake Constance)|Rotach]], [[Brunnisach]], [[Linzer Aach|Seefelder Aach]], [[Stockacher Aach]], [[Salmsacher Aach]], the [[Aach (Lake Constance, Arbon)|Aach near Arbon]], [[Steinach (Lake Constance)|Steinach]], [[Goldach (river)|Goldach]] and the [[Old Rhine (Fußach)|Old Rhine]]. The outflow of the Obersee is the [[Seerhein]], which in turn is the main tributary of the Untersee. The most important tributary of the Untersee is the [[Radolfzeller Aach]]. The source of the Radolfzeller Aach is the [[Aachtopf]], a [[karst spring]] whose waters mostly derive from the [[Danube Sinkhole]]. Therefore, the [[Danube]] is indirectly also a tributary of the Rhine.
{| class="wikitable sortable"
|+ The ten biggest tributaries of the Obersee by discharge volume<ref>Landesanstalt für Umwelt, Messungen und Naturschutz in Baden-Württemberg: [http://www.lubw.baden-wuerttemberg.de/servlet/is/8849/jhdt_hochwasser.pdf?command=downloadContent&filename=jhdt_hochwasser.pdf ''Informationen zum Jahrhunderthochwasser 1999.''] {{Webarchive|url=https://web.archive.org/web/20131023235412/http://www.lubw.baden-wuerttemberg.de/servlet/is/8849/jhdt_hochwasser.pdf?command=downloadContent&filename=jhdt_hochwasser.pdf |date=2013-10-23 }} (pdf; 24&nbsp;kB)</ref> with its catchment areas:<ref>Internationale Gewässerschutzkommission für den Bodensee (publ.): ''Der Bodensee. Zustand – Fakten – Perspektiven.'' IGKB, Bregenz, 2004, {{ISBN|3-902290-04-8}}, [http://www.hydra-institute.com/igkb/IGKB%201.2.pdf Kapitel 1.2] {{webarchive|url=https://web.archive.org/web/20120514054950/http://www.hydra-institute.com/igkb/IGKB%201.2.pdf |date=2012-05-14 }} (pdf; 1.2&nbsp;MB)</ref>
|-
! align="left"| River
! align="left"| Average discharge<br />[m<sup>3</sup>/s] (1978–1990)
! align="left"| Discharge<br />in %
! align="left"| [[Drainage divide|Catchment]]<br />[km<sup>2</sup>]
! align="left"| Catchment<br />in %
|-
|Alpine Rhine || align="right"| 233 || align="right"| 61.1 || align="right"| 6,119 || align="right" | 56.1
|-
|Bregenzer Ach || align="right"| 48 || align="right"| 12.6 || align="right" | 832 || align="right"| 7.6
|-
|Argen || align="right"| 19 || align="right"| 5.3 || align="right"| 656 || align="right"| 6.0
|-
|Old Rhine<br />(Rhine Valley Canal) || align="right"| 12 || align="right"| 3.1 || align="right"| 360 || align="right"| 3.3
|-
|Schussen || align="right"| 11 || align="right"| 2.9 || align="right" | 822 || align="right"| 7.5
|-
|Dornbirner Ach || align="right" | 7.0 || align="right"| 1.8 || align="right"| 196 || align="right"| 1.8
|-
|Leiblach || align="right"| 3.3 || align="right" | 0.9 || align="right"| 105 || align="right"| 1.0
|-
|Seefelder Aach || align="right"| 3.2 || align="right" | 0.8 || align="right"| 280 || align="right"| 2.6
|-
|Rotach || align="right"| 2.0 || align="right"| 0.5 || align="right"|130 || align="right"| 1.2
|-
|Stockacher Aach || align="right"| 1.6 || align="right"| 0.4 || align="right"| 221 || align="right"| 2.0
|- style="background:#EEEEEE;" class="sortbottom"
|''Sum of the<br />10 main tributaries'' || align="right" | ''340'' || align="right"| ''89.6'' || align="right"| ''9,721'' || align="right"| ''89.2''
|- style="background:#DDDDDD;" class="sortbottom"
|Total inflow || align="right"| 381 || align="right"| 100.0 || align="right" | 10,903 || align="right" | 100.0
|}<!-- <small>Empty cells mean there is no data in the publications.</small> -->

Because the Alpine Rhine brings with it [[drift (geology)|drift]] from the mountains and deposits this material as [[sedimentation|sediment]], the Bay of Bregenz will silt up in a few centuries time. The silting up of the entire Lake Constance is estimated to take another ten to twenty thousand years.

=== Outflows, evaporation, water extraction ===
The outflow of the Untersee is the [[High Rhine]] with the [[Rhine Falls]] at [[Schaffhausen]]. Both the average precipitation of 0.45&nbsp;km<sup>3</sup>/a and evaporation which averages 0.29&nbsp;km<sup>3</sup>/a cause a net change in the level of Lake Constance that is less when compared to the influence of the inflows and outflows.<ref name="Gewässerschutzkommission"/> Further quantities of lake water are extracted by municipal waterworks around the lake and the water company of [[Bodensee-Wasserversorgung]].

=== Islands ===
{{Anchor|Island anchor}}
[[File:Insel Mainau im Bodensee.jpg|thumb|The island of Mainau]]
{{Main|List of islands in Lake Constance}}
In Lake Constance there are ten [[island]]s that are larger than {{cvt|2,000|m2}}.

By far the largest is the [[island of Reichenau]] in the Untersee, which belongs to the municipality of [[Reichenau (Konstanz)|Reichenau]]. The former [[Reichenau Abbey|abbey of Reichenau]] is a [[UNESCO]] [[World Heritage Site]] due to its three early and highly medieval churches. The island is also known for its intensive cultivation of [[fruit]] and [[vegetables]].

The island of [[Lindau (island)|Lindau]] is located in the east of the Obersee, and is the second largest island. On it is the old town and main railway station of Lindau.

The third largest island is [[Mainau]] in the southeast of Lake Überlingen. The owners, the family of [[House of Bernadotte|Bernadotte]], have set up the island as a tourist attraction and created botanical gardens and wildlife enclosures.

Relatively large, but uninhabited and inaccessible because of their status as nature reserves, are two islands off the [[Wollmatinger Ried]]: the [[Triboldingerbohl]] which has an area of {{cvt|13|ha}} and Mittler or Langbohl which is just {{convert|3|ha|spell=in}} in area.

Smaller islands in the Obersee are:
* Dominican Island (''Dominikanerinsel'') separated by a six-metre-wide ditch from the old town of [[Konstanz|Constance]] which is home to the Steigenberger Hotel ({{convert|2|ha|spell=in|disp=sqbr}})
* The tiny island of [[Hoy (Lake Constance)|Hoy]] near Lindau
* The ten artificial islands on the Rhine Causeway on the Fußach side
* The little island by the port of [[Romanshorn]]
* The Wollschweininsel (officially ''Wulesaueninsle'') by the Seepark in [[Kreuzlingen]]

In the Untersee are:
* the islands of [[Werd (Lake Constance)|Werd]], [[Mittleres Werdli]] and [[Unteres Werdli]] which together form the [[Werd Islands]] group are located at the outflow of the Rhine from the Untersee at Stein am Rhein into the [[High Rhine]].
* The so-called [[Liebesinsel (Lake Constance)|Liebesinsel]] ("Love Island", {{cvt|2,620|m2|disp=sqbr}}, southwest of the Mettnau peninsula.

=== Peninsulas ===
In Lake Constance there are several peninsulas which vary greatly in size:
* The [[Bodanrück]], the largest peninsula, separates the Überlinger See (Obersee) from the Untersee. It covers an area of {{cvt|112|km2}}.
* The [[Mettnau]] in the Untersee, which extends towards the Island of Reichenau, separates Zeller See in the south from the Markelfinger Winkel in the north. It has a surface area of {{cvt|1.7|km2}}.
* The [[Höri (Lake Constance)|Höri]], (about 45-square-kilometres) also extends towards the Island of Reichenau, and separates the Zeller See to the north from the Rheinsee to the south.
* In the southeast, near the mouth of the new Rhine Canal, the [[Rhine Delta (Lake Constance)|Rohrspitz]] juts out about {{cvt|1.2|km}} into the lake and forms the western perimeter of the Bay of Fußach. It has an area of about 50 hectares.
* The [[Wasserburg (Lake of Constance)|Wasserburg]] peninsula has a castle, Schloss Wasserburg, and the parish church of St. George. The peninsula is on the northeastern shore of the Obersee between the Bay of Nonnenhorn in the west and Bay of Wasserburg in the east. It has an area of {{cvt|2.3|ha}} and was an island until 1720, when the [[Fugger]]s built a causeway. In March 2009, 27 people lived on the peninsula.
* The [[Galgeninsel]] ("Gallows Island") in the Bay of Reutin is also a peninsula that was formerly an island. It is only 0.16 hectares in area.

=== Shore ===
[[File:BodenseeSandstrand03.jpg|thumb|Sandy shore at the [[Marienschlucht]]]]
The shores of Lake Constance consist mainly of gravel. In some places there are also sandy beaches, such as the [[Rohrspitz]] in the Austrian section of the lake, the [[Langenargen]] and [[Marienschlucht]].

According to the data of the International Water Protection Commission for the Lake Constance, the approximate shore length is {{cvt|273|km}} (see [[Coastline paradox]]). The inflow of water is constantly changing, mainly due to rain and the snow melt in the Alps. Its average surface area is about {{Höhe|395|DE-NN}} (in Switzerland the absolute value is slightly higher in m above sea level). The more or less regular seasonal fluctuations in the water level also lead to slight variations in shore length and differences in the shore zone habitats (depending on high and low water).

=== Transportation ===
==== Road ====
Roads westbound [[Bundesstraße 33]] (B 33, highway), [[Bundesautobahn 81]] (A&nbsp;81), at Stockach, Konstanz: [[Bundesautobahn 98]] (A&nbsp;98), Switzerland: [[Autobahn 7 (Switzerland)|Autobahn 7]] (A7), [[Autobahn 1 (Switzerland)|Autobahn 1]] (A 1), [[Autobahn 23 (Switzerland)|Autobahn 23]] (A 23) and eastbound at Bregenz [[Rheintal/Walgau Autobahn]] (A&nbsp;14), at Lindau [[Bundesautobahn 96]] (A&nbsp;96), [[Bundesstraße 31]] (B&nbsp;31)

==== Ship / Ferry ====
{{main|:de:Bodenseehäfen}}
[[File:MS Karlsruhe in der Konstanzer Hafeneinfahrt.jpg|thumb|MS Karlsruhe arriving Constance]]
[[File:Schifffahrt Bodensee.png|thumb|right|Ship routes on Lake Constance and the High Rhine]]
There are eight main harbors offering boat services across the [[Obersee (Lake Constance)|Upper Lake]]:

;Austria:
* [[Bregenz]]

;Switzerland:
* [[Rorschach, Switzerland|Rorschach]]
* [[Romanshorn]]

;Germany:
* [[Lindau (Bodensee)|Lindau]]
* [[Friedrichshafen]]
* [[Meersburg]]
* [[Unteruhldingen]] (touristic harbor)
* [[Konstanz]]

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* '''[[Konstanz]]''': 1839/41 Bau des nördlichen Hafens (13.000 m<sup>2</sup>) am „Konzilgebäude“; 1846/55 Bau der [[Werft]]; 1863 Anschluss an die Eisenbahn mit [[Bahnhof Konstanz|Bahnhof]] und zweiter, südlicher Hafen (55.000 m<sup>2</sup>) für Eisenbahntrajekte nach Lindau und Bregenz (bis 1917); 1890 Vereinigung der beiden Hafenteile. Seit 1993 ist die [[Imperia (Statue)|„Imperia“]] Wahrzeichen des Hafens. Ab 2005 Bau von [[Schwimmanleger]]n für den [[Katamaran Friedrichshafen–Konstanz|Katamaran]] und zwei Kursschiffe. Von Konstanz aus sind alle Verbindungen direkt möglich: Nach Schaffhausen, Überlingen, Bregenz und Rorschach. Die Werft wird nur noch als Werkstatt benutzt. Die Stadt ist Heimathafen der „badischen“ Schiffe, Sitz der BSB und der Stadtwerke Konstanz.

* '''[[Meersburg]]''': 1851/1852 Bau der steinernen [[Mole]]. Heute sind im Hafen zwei Schwimmanleger; ein weiterer Liegeplatz ist an der Außenmole. Kleiner aber wichtiger Umsteigehafen zum [[Überlinger See]] mit der Insel [[Mainau]]. Bis 1974 war der Meersburger Hafen offiziell ein DB-Bahnhof, der einzige in Deutschland ohne Gleisanschluss.
[[Datei:Lindau Hafen Luftbild.jpg|mini|Auf diesem Luftbild ist die Anbindung des Hafens an die Eisenbahn in Lindau gut erkennbar.]]

* '''[[Friedrichshafen]]''': 1811 Bau des „Stadthafens“, später für Dampfschiffe; 1846 Ausbau, 1851 Erweiterung (zum Teil mit Pfahlreihen) und Werft; 1854 Eisenbahnanschluss und erster [[Hafenbahnhof]]; 1869 Eisenbahntrajekt nach Romanshorn (bis 1976), ab 1929 auch für Kraftfahrzeuge; 1933 heutiges [[Bahnhof Friedrichshafen Hafen|Hafenbahnhofsgebäude]]; 1944 schwere Zerstörungen durch [[Bodenseeschifffahrt im Zweiten Weltkrieg|Luftangriffe]]; 2005 Bau eines Katamarananlegers; Liegeplatz für Boote der [[Wasserschutzpolizei]], des [[Kontrolleinheit See|Zolls]] und der [[Löschboot|Feuerwehr]]. Bis 1976 wurden Eisenbahnwaggons und Lokomotiven verschifft. Die [[Bodensee-Schiffsbetriebe#Werft|Werft]] dient nur noch der Reparatur und Revision der Schiffe. Friedrichshafen ist der Heimathafen der „württembergischen“ Schiffe der BSB und ein bedeutender [[Verkehrsknotenpunkt]], nicht nur für die Schifffahrt vom westlichen und östlichen Obersee, der [[Fährlinie Friedrichshafen–Romanshorn|Autofähre]] nach Romanshorn und dem Katamaran nach Konstanz, sondern auch mit den Bahn- und Flugverbindungen sowie den Rundflügen mit dem [[Zeppelin NT]]. {{Hauptartikel|Bodensee-Trajekte}}

* '''[[Lindau (Bodensee)|Lindau]]''': Seit 1200 befestigte Hafenstadt; 1812 steinerne Hafenmole für fast 100 Segelschiffe; 1848 Schiffswerft (bis 1961); 1854 Eisenbahnanschluss des Hafens über den [[Lindauer Bodenseedamm]] zum Hauptbahnhof auf der Insel; 1856 Ausbau des Hafens mit [[Bayerischer Löwe|Löwen-Statue]] und [[Neuer Lindauer Leuchtturm|„Neuem Leuchtturm“]] an der Einfahrt; 1869 Trajektverbindung nach Romanshorn und Konstanz; Heimathafen der „bayerischen“ Schiffe der BSB.<ref>[http://buergerwiki.net/Lindauer_Hafen Informationen zum Hafen Lindau]</ref>
[[Datei:MS Austria 2.JPG|mini|Das 75-jährige österreichische Flaggschiff ''[[Austria (Schiff, 1939)|Austria]]'' im Hafen von Bregenz vor dem Pfänder.]]
* '''[[Bregenz]]''': 1842/46 Bau einer hölzernen Hafenanlage für sechs Dampfschiffe; 1850 Ersatz durch eine Steinmole; 1872 Eisenbahnanschluss; 1884 Gründung der österreichischen Bodenseeflotte mit Heimathafen Bregenz; ab 1881 Hafenerweiterung mit [[Trockendock]] (bis 1940) und Trajektverbindungen nach Romanshorn, Konstanz und Friedrichshafen (bis 1913/17).<ref>[http://www.hafen-bregenz.at/index.asp Informationen zum Hafen Bregenz]</ref> Der Hafen besteht seitdem aus einem „großen Molo“ als Wellenbrecher, einem mittleren „Personenmolo“ mit Hafengebäude und Liegeplätze für drei Schiffe im Einsatz sowie einem „Reservemolo“ für Schiffe außer Betrieb. Zwischen diesen beiden wurde 1977 ein eiserner Steg mit Tankstelle errichtet. Bei der Sanierung 1996 wurden Liegeplätze für Privatboote geschaffen.<ref>''Über 100 Jahre Österreichische Bodenseeschifffahrt 1884–1984. Heimatkundliche Unterrichtsbildreihe.'' Herausgeber: Amt der Vorarlberger Landesregierung Schulmediencenter, Bregenz 1984/2003.[http://www.vobs.at/fileadmin/user_upload/smc/Bildreihen/Begleittexte/3500085_Bodenseeschifffahrt_Text.pdf] (PDF)</ref>

* '''[[Rorschach, Switzerland|Rorschach]]''': 1840 neue Hafenmole für den immer noch zu kleinen Hafen, deshalb 1862 Erweiterung zur heutigen Größe; 1856 unmittelbarer Eisenbahnanschluss; Heimathafen der drei kleinen [[Schweizerische Bodenseeschiffahrtsgesellschaft|SBS-Schiffe]] des ehemaligen [[Schifffahrtsbetrieb Rorschach|Schifffahrtsbetriebs Rorschach]].<ref>[http://www.bodensee-schiffe.ch/unterwegs/haefen/rorschach1.html Hafenplan Rorschach]</ref>

* '''[[Romanshorn]]''': Aus dem kleinen Hafen (1844) des Fischerdorfes entstand bis 1870 der flächenmäßig größte Bodenseehafen mit Gleisanschluss (1855) und Bahnhof direkt am Hafen und Trajektverbindungen nach Deutschland. Als Verkehrsknotenpunkt wurde der Heimathafen der vier großen SBS-Schiffe so bedeutsam, dass sich der Ort um den Hafen entwickelte. Die Trajekte wurden durch die Autofährlinie Friedrichshafen-Romanshorn abgelöst. Die leistungsfähige Werft ist heute die einzige dieser Art am Bodensee.<ref>[http://bodensee-schiffe.ch/unterwegs/haefen/hafenromanshorn.html Hafenplan Romanshorn]</ref> {{Hauptartikel|Fährlinie Friedrichshafen–Romanshorn}}

* '''[[Unteruhldingen]]''': Der Ausflugs- und ehemalige Fährhafen befindet sich zwischen der Marina und dem ehemaligen Bahnhof. Die [[Bodensee-Schiffsbetriebe]] bieten Verbindungen nach Konstanz, Mainau, Überlingen, Meersburg, Daisendorf und Rorschach an.<ref>{{Internetquelle |url=https://www.bsb.de/de/bodensee-erlebnisse/rundfahrten/uhldingen |titel=Rundfahrten ab Unteruhldingen |hrsg=Bodensee-Schiffsbetriebe |abruf=2021-06-06}}</ref>-->

Additionally, [[ferry|car ferries]] link Romanshorn to Friedrichshafen, and Konstanz to Meersburg.<ref name=map500/><ref name=mapGPBW1/> Between 1869 and 1976, there used to be [[Lake Constance train ferries|train ferries]] across the lake.

Several smaller harbors on the Upper Lake offer boat trips along the German or Swiss coast (with one continuing over the [[Alter Rhein|Old Rhine]] to [[Rheineck]]).

The harbour in Konstanz is also served by the ''[[Schweizerische Schifffahrtsgesellschaft Untersee und Rhein]]'' (URh), which operates via the ''[[Seerhein]]'', [[Untersee (Lake Constance)|Lower Lake]] and [[High Rhine]] to [[Schaffhausen]].<ref>{{Cite web |url=https://www.urh.ch/en/ |title=''URh'' website |access-date=2024-06-24}}</ref> It docks at the harbours of [[Kreuzlingen]], Konstanz, [[Gottlieben]], [[Ermatingen]], [[Reichenau Island|Reichenau]], [[Mannenbach]], [[Berlingen, Switzerland|Berlingen]], [[Gaienhofen]], [[Steckborn]], [[Hemmenhofen]], Wangen, [[Mammern]], [[Öhningen]], [[Stein am Rhein]], [[Diessenhofen]], [[Büsingen am Hochrhein|Büsingen]] and Schaffhausen. [[Radolfzell]] and [[Iznang]] are also linked by a boat line over the Lower Lake (to Konstanz).

====Rail====
{{Main|Lake Constance Belt Railway||Bodensee S-Bahn}}
[[File:Bregenz asv2022-10 img32 Zug der S1 am Bodensee.jpg|thumb|right|[[Vorarlberg S-Bahn]] (S1) trainset on the [[Vorarlberg Railway]] line]]
A network of several [[railway line]]s surrounds the lake. The lines are operated by regional train services ([[S-Bahn]], [[RegioExpress]], [[Regional-Express]]) spreading over four countries ([[Austria]], [[Germany]], [[Liechtenstein]], [[Switzerland]]).<ref>{{cite web |title=FahrplanNetzkarte 2024 |lang=de |url=https://www.thurbo.ch/fileadmin/user_upload/PDF/2024_Liniennetzplan_Zuerich_Ostschweiz_Bodensee.pdf |date=2023-12-10 |access-date=2023-12-18 |publisher=THURBO |archive-date=16 December 2023 |archive-url=https://web.archive.org/web/20231216083155/https://www.thurbo.ch/fileadmin/user_upload/PDF/2024_Liniennetzplan_Zuerich_Ostschweiz_Bodensee.pdf |url-status=dead }}</ref> In Switzerland, they belong to [[S-Bahn St. Gallen]] and trains are operated by [[THURBO]] ([[Swiss Federal Railways]], SBB), [[Südostbahn]] (SOB) and [[Appenzell Railways]] (AB).<ref>{{cite web |title=''Fahrplan-Netzkarte 2024'' [Railway network and services near Lake Constance 2024] |lang=de |url=https://www.thurbo.ch/fileadmin/user_upload/PDF/2024_Liniennetzplan_Zuerich_Ostschweiz_Bodensee.pdf |date=2023-12-10 |access-date=2023-12-18 |publisher=THURBO |archive-date=16 December 2023 |archive-url=https://web.archive.org/web/20231216083155/https://www.thurbo.ch/fileadmin/user_upload/PDF/2024_Liniennetzplan_Zuerich_Ostschweiz_Bodensee.pdf |url-status=dead }}</ref> The so-called [[Lake Constance Belt Railway|belt railway]] ({{lang|de|Bodensee-Gürtelbahn}}) along the northern shore is operated by [[DB Regio]] and [[SBB GmbH]]. In Austria and Liechtenstein, train services are operated by [[Austrian Federal Railways]] (ÖBB) for the [[Vorarlberg S-Bahn]]. Regional train services around Lake Constance are marketed as [[Bodensee S-Bahn]].

[[Railway station]]s close to harbours are, among others: {{rws|Bregenz Hafen}}, {{rws|Friedrichshafen Hafen}}, {{stn|Konstanz}}, {{rws|Kreuzlingen Hafen}}, {{stn|Lindau-Insel}}, {{stn|Radolfzell}}, {{rws|Romanshorn}} and {{rws|Rorschach Hafen}}.

Long-distance trains ([[Railjet|RJ/RJX]], [[EuroCity|EC/ECE]], [[Intercity (Deutsche Bahn)|IC (DB)]]/[[InterCity (Switzerland)|IC (SBB)]], [[InterRegio|IR]], [[Interregio-Express|IRE]]) link larger lakeside railway stations (e.g., {{rws|Bregenz}}, {{rws|Friedrichshafen Stadt}}, {{stn|Konstanz}}, {{stn|Lindau-Reutin}}, {{rws|Romanshorn}}) with major cities.

====Air====
Two [[airport]]s are located near the lake's shores: [[Friedrichshafen Airport]] (Germany) and [[St. Gallen–Altenrhein Airport]] (Switzerland). [[Zeppelin NT]] offers touristic [[zeppelin]] flights around Lake Constance departing from Friedrichshafen Airport.<ref>{{cite web |url=https://zeppelinflug.de/en/zeppelin-flights/overview?_gl=1*1l0443c*_up*MQ..&gclid=CjwKCAjw59q2BhBOEiwAKc0ijbqc72wwLctPsSo5TtMD1eivL9Njvt9B0cjOVffuEvhcLQYvvIseyhoCpZsQAvD_BwE |title=Overview of zeppelin flights in Germany |publisher=zeppelinflug.de |access-date=2024-09-04}}</ref>

=== Climate ===
[[File:Bodenseesturm.jpg|thumb|Summer storm – view of the [[Luitpoldkaserne (Lindau)|Luitpold Barracks]] in Lindau]]
The climate of the Lake Constance area is characterised by mild temperatures with moderate gradients, thanks to the balancing and retarding effect of the large body of water. 

It has a [[subtropical]] microclimate, which allows the cultivation of some exotic fruits and trees. Constance counts 2069 sunshine hours a year and is therefore considered one of the sunniest cities in Germany.

Winters are generally short and mild, although night temperatures can fall under 0°C, especially from December to February. Typically day temperatures range between +5 and +12°C, while nights with +1 to +8°C on average stay cold, though mostly without long and severe frosts.

The [[Föhn]], a warm wind from the [[Mediterranean Sea]], that regularly blows through the Alps, can cause temperatures between 15 and 20°C with sunshine for several days, while on the other hand fog creates a few cold days between 1 and 5°C each year. Generally, Lake Constance is affected more by fog than neighboring regions more inland. 

Spring goes from March to May and is usually sunny, with day temperatures between 15 and 22°C but still relatively cold water. This is also resulting in still cold night temperatures that range between 4°C in March and 12°C in May only. 

As the lake temperature heats up by the increasing warm days, the nights are also becoming milder, though moderated a little bit by the height and lake. This results in average morning lows of 16-18°C during the high summer months. Lake Constance counts one of the highest amount of [[tropical nights]] in Germany (lowest temperature at 20°C or more). 

The days in Summers (June-September) are warm to hot with day temperatures of 26-33°C on average, decreasing to around 20°C until the end of September. Humidity levels raise noticeable and temperatures often move up to 35°C between June and August. This increases the [[heat index]], causing Lake Constance to have a stressful climate.

The region receives most of its sunny days during high summer. In the recent years, in 2018 and 2022, the water levels fall to new record lows due to weeks without significant rain. On the other hand, the closeness to the Alps can cause thunderstorms in the evenings that sometimes occur out of nowhere.

While the official bathing season ends in September, the average lake temperature stays around 20°C until October. Autumn is generally the time when Lake Constance starts to experience more foggy mornings again, but the day temperatures still range between 21 in the beginning and 10-12°C at the end of the season. Night temperatures fall from 13°C in September to an average of 5°C in November.

Lake Constance is one of the best known wine growing regions in Germany and experiences several outdoor events during harvest time in autumn. 
 
[[File:Foehnwind am bodensee.jpg|thumb|left|Waves raised by Föhn winds]]
Lake Constance is also considered to be a risky and challenging lake for water sports because of the danger of gusty winds which can whip up waves as the weather changes suddenly. The most dangerous wind is the föhn, a warm down-slope wind from the Alps, which spreads out across the water, especially through the [[Alpine Rhine Valley]] and can generate waves several metres high.

Similarly dangerous for those unfamiliar with the area, are the sudden stormy gusts of wind during summer thunderstorms. They constantly claim victims from the water sports fraternity. During a thunderstorm in July 2006, waves reached heights of up to 3.50 metres.

For these reasons, there is a storm warning system in all three neighbouring countries. For [[storm warning]] purposes, Lake Constance is divided into three warning regions (west, centre and east). Warnings can be issued for each region independently. A "high winds" warning will be issued when [[squall]]s are expected of between 25 and 33&nbsp;[[knot (unit)|knots]] or registering [[wind speed|force]] 6 to 8 on the [[Beaufort scale]]. A [[gale warning]] announces the likelihood of gale-force winds, i.e. those at speeds as of 34 knots or more or force 8 on the Beaufort scale. In order to issue these warnings, orange-coloured flashing lights are installed around the lake, which flash at a frequency of 40 times per minute for high winds or 90 times per minute for gales. It can happen that, due to the differently regulated responsibilities and assessments, a gale warning is issued on the Swiss side of the Obersee, but not on the German or Austrian shores, and vice versa. Ships and ferries on Lake Constance indicate a gale warning by hoisting a ''Sturmballon'' ("storm ball") up the mast.

==== Freeze over ====
[[File:BodenseeGefroren.jpg|thumb|right|Frozen lake surface: skating in the [[Markelfinger Winkel]]]]
[[File:Seegfrörni 1963.jpg|thumb|right|Freezing of Lake Constance in 1963]]
A one-hundred year event is the freezing over of Lake Constance, when the Lower Lake and the Upper Lake are completely frozen over so that people can safely cross the lake on foot. The last so-called ''Seegfrörne'' ([[Alemannic German|Alemannic]]) event was in 1963. The following is a list of [[Anno Domini|years]] in which Lake Constance froze over partially or completely:<ref>{{cite book |last=Meichle |first=Friedrich |chapter=Seegfrörne und Eisprozession in Vergangenheit und Gegenwart |title=Schriften des Vereins zur Geschichte des Bodensees und seiner Umgebung |volume=81 |year=1963 |pages=145–170 |issn=0342-2070 |language=de}}</ref><ref>{{cite book |last=Dobras |first=Werner |title=Seegfrörne: die spannende Geschichte der Seegfrörnen von 875 bis heute. 2. veränderte Auflage |publisher=Stadler |location=Konstanz |year=1992 |isbn=3-7977-0266-3 |language=de}}</ref>

*875, 895
*1074, 1076
*1108
*1217, 1227, 1277
*1323, 1325, 1378, 1379, 1383
*1409, 1431, 1435 (complete), 1460, 1465, 1470, 1479
*1512, 1517, 1553, 1560 (complete), 1564, 1565, 1571, 1573 (complete)
*1684, 1695 (complete)
*1788, 1796 (complete)
*1830 (complete), 1880 (complete)
*1929, 1963 (complete)

Certain parts of the lake freeze over more frequently, mainly due to their shallow depth of water and shelter, as is the case, for example, of the so-called [[Markelfinger Winkel]] between the municipality of [[Markelfingen]] and the [[Mettnau]] peninsula.

==== Floods ====
* A [[100-year flood]] around June 1999 ([[Pfingsthochwasser 1999]]) raised the level about 2 metres above normal, flooding harbors and many shoreline buildings and hotels.
* In late August 2005, heavy rain raised the level by more than {{cvt|70|cm}} in a few days. The rains caused widespread flooding and washed out highways and railroads.
* Frequent rainfall and snowmelt in the summer of 2024 raised water levels to {{cvt|68|cm}} above normal level.

{{wide image|Panorama Hochwasser im Rheinholz.jpg|600px|Flooding on the shore of Lake Constance, May 2013}}

=== International borders ===
[[File:Lac de constance.jpg|thumb|Lake Constance, seen from a vineyard]]
The lake lies where the countries of Austria, Germany, and Switzerland meet.<ref name="Kramsch">{{cite book |last=Kramsch |first=Olivier Thomas |editor1-last=Brunet-Jailly |editor1-first=E. |title=Border Disputes: A Global Encyclopedia, Volume 2 |date=2015 |publisher=ABC-CLIO |isbn=978-1-61-069024-9 |page=453 |chapter-url=https://books.google.com/books?id=k9g5CgAAQBAJ&q=%22lake+constance%22 |chapter=Austria-Germany-Switzerland: Lake Constance (Konstanz)}}</ref> Beyond areas less than {{cvt|25|m}} deep, considered to be under the jurisdiction of the nearest country, there is no legally binding agreement as to where the borders lie between the three countries.{{r|Kramsch}}<ref name="Kahn 2004">{{cite book |url=https://books.google.com/books?id=V01T5VI4nZ4C&pg=PA233 |title=Die deutschen Staatsgrenzen: rechtshistorische Grundlagen und offene Rechtsfragen ("The German national borders: legal-historical foundations and open legal questions") |author=Kahn, Daniel-Erasmus |publisher=Oxford University Press |year=2004 |isbn=978-3-16-148403-2}}</ref> However, Switzerland holds the view that the border runs through the middle of the lake, Austria is of the opinion that the contentious area belongs to all the states on its banks, which is known as a "[[condominium (international law)|condominium]]", and Germany holds an ambiguous opinion.{{r|Kramsch}}<ref>Jennings, Ken (16 June 2014) [http://www.cntraveler.com/stories/2014-06-16/lake-constance-maphead "The Borderless Black Hole in the Middle of Europe"] ''[[Conde Nast Traveler]]''</ref> Legal questions pertaining to ship transport and fishing are regulated in separate treaties.

Disputes occasionally arise. One concerns a [[houseboat]] which was moored in two states ([[European Court of Justice|ECJ]] c. 224/97 Erich Ciola); another concerns the rights to fish in the Bay of Bregenz. In relation to the latter, an Austrian family was of the opinion that it alone had the right to fish in broad portions of the bay. However, this was accepted neither by the Austrian courts nor by the organs and courts of the other states.<ref>Mark, David and Smith, Barry, et al., [http://ontology.buffalo.edu/smith//baarle/bizarre_shapes.htm "Bizarre Shapes: 100 Geographic Monsters"]</ref>

== Ecology ==
=== Flora ===
Until the 19th century, Lake Constance was a natural lake. Since then, nature has been heavily influenced by [[clearing (geography)|clearing]] and the cultivation of much of the land around its shores. However, some near-natural areas have been largely conserved, especially in the nature reserves, or were re-naturalised. As a result, the Lake Constance region has some unusual ecological features. These include the large forested area on the [[Bodanrück]], the occurrence of [[Gentiana pneumonanthe|marsh gentian]] and [[orchid]]s of the genera ''[[Dactylorhiza]]'' and ''[[Orchis]]'' in the Wollmatinger Ried, and the [[Siberian iris]] (''Iris sibirica'') in the [[Eriskircher Ried]], which was therefore given its own name.<ref name="Planet Wissen">[http://www.planet-wissen.de/natur_technik/fluesse_und_seen/der_bodensee/index.jsp Planet Wissen – Bodensee]</ref> One unique species among the local flora is the [[Lake Constance forget-me-not]] (''Myosotis rehsteineri''), whose habitat is restricted to undisturbed limestone gravel beaches.

=== Fauna ===
==== Birds ====
[[File:Halbinsel Mettnau.JPG|thumb|The Mettnau peninsula]]
Lake Constance is also the home of numerous bird species, many of which nest in its nature reserves, such as the [[Wollmatinger Ried]] or the [[Mettnau]] peninsula. 412 species have so far been recorded.<ref>[http://www.bodensee-ornis.de/informationen-zum-bodensee/beobachtungsgebiete/ Ornithologische Arbeitsgemeinschaft Bodensee: Beobachtungsgebiete] {{webarchive|url=https://web.archive.org/web/20160919054010/http://www.bodensee-ornis.de/informationen-zum-bodensee/beobachtungsgebiete/ |date=2016-09-19 }}</ref>

===== Songbirds =====
The ten most common breeding bird species at Lake Constance according to a 2000–2003 survey in descending order are the: [[Common blackbird|blackbird]], [[chaffinch]], [[house sparrow]], [[great tit]], [[Eurasian blackcap|blackcap]], [[common starling|starling]], [[European robin|robin]], [[common chiffchaff|chiffchaff]], [[European greenfinch|greenfinch]], and [[blue tit]].<ref>''Aufgelistet. Die 10 häufigsten Brutvögelarten…'' In: ''[[Südkurier]].'' 22 October 2010.</ref>

===== Waterfowl =====
[[File:Blässhuhn Fulica atra 03.JPG|thumb|Coot in Hard am Bodensee]]
In spring, the Lake Constance is an important breeding ground, especially for the [[Eurasian coot|coot]] and [[great crested grebe]].<ref>{{Cite web |url=http://www.bodensee-ornis.de/informationen-zum-bodensee/ |title=Fluctuating water levels |access-date=2017-09-03 |archive-url=https://web.archive.org/web/20160916032018/http://www.bodensee-ornis.de/informationen-zum-bodensee/ |archive-date=2016-09-16 |url-status=dead }}</ref> Typical waterfowl include the: [[Northern shoveler|shoveler]], [[Common goldeneye|goldeneye]], [[goosander]], [[Common pochard|pochard]], [[grey heron]], [[Northern pintail|pintail]], [[tufted duck]] and [[mallard]].<ref>Information board on the Überlingen promenade.</ref>

In December 2014, 1,389 [[great cormorant|cormorant]] were counted. The International Lake Constance Fishery Association (IBF) estimates the food requirements of the cormorants on Lake Constance at 150 tonnes of fish annually.<ref name="Franz Domgörgen 2015">Franz Domgörgen: ''Stabile Verhältnisse im Vogelparadies.'' ''Stabile Verhältnisse im Vogelparadies.'' In: ''Südkurier.'' 3 January 2015.</ref>

===== Overwintering =====
Lake Constance is an important overwintering area for around 250,000 birds.<ref name="BVET">[https://www.news.admin.ch/de/nsb?id=7771 Bundesamt für Veterinärwesen: Forschungsprojekt "Constanze" am Bodensee gestartet] {{Webarchive|url=https://web.archive.org/web/20150123131940/https://www.news.admin.ch/message/?lang=de&msg-id=7771 |date=23 January 2015 }}</ref> annually. Bird species such as the [[dunlin]], the [[Eurasian curlew|curlew]] and the [[Northern lapwing|lapwing]] overwinter at Lake Constance.<ref>[http://www.bodensee-ornis.de/projekte/brachvogelprojekt/ Brachvogelprojekt]</ref> In the middle of December 2014 there were 56,798 heron, 51,713 coot and 43,938 pochard.<ref name="Franz Domgörgen 2015"/> In November/December are about 10,000 to 15,000 [[red-crested pochard]] and 10,000 great crested grebe on Lake Constance.<ref>Franz Domgörgen: ''Wasservögel bleiben Bodensee treu.'' In: ''Südkurier.'' 8 August 2014, p. 23.</ref>

===== Migration =====
During migration in late autumn there are also numerous [[loons]] on the lake ([[Black-throated loon|black-throated]] and [[red-throated loon]], as well as a few [[great northern loon]]s). Lake Constance is also very important as a staging post during the [[bird migration]]. Bird migration is often inconspicuous and most noticeable when there are special weather conditions that make day migration obvious. Only where there is a prolonged spell of widespread low-pressure is it common to observe the congestion of large groups of migratory birds. This can often be observed in autumn on the [[Eriskircher Ried]] on the northern shore of Lake Constance. This is where broad front migration converges on the lake and birds then try to move along the shore towards the northwest. The importance of Lake Constance as an important area for resting and overwintering is underlined by the Max Planck Institute for Ornithology's Radolfzell Bird Observatory (''Vogelwarte Radolfzell''), which is the [[bird ringing]] centre for the German states of Bavaria, Baden-Württemberg, Berlin, Rhineland-Palatinate and the Saarland as well as for Austria, and which researches bird migration.<ref>{{Cite web |url=http://www.orn.mpg.de/~vwrado/templates/de/birdrining.html |title=Max-Planck-Forschungsstelle für Ornithologie - Vogelberingung |access-date=2017-09-03 |archive-url=https://web.archive.org/web/20070305053525/http://www.orn.mpg.de/~vwrado/templates/de/birdrining.html |archive-date=2007-03-05 |url-status=dead }}</ref>

==== Fish ====
Around 45 species of fish live in Lake Constance. The annual haul from fishing is 1.5 million kg. Unusual species occurring here considering the location of the lake are the [[Coregonus|whitefish]] (''Coregonus'' spec.) and the [[Arctic char]] (''Salvelinus alpinus''). Fish that are important for the fishing industry are:
* [[Bodenseefelchen]] (German: also ''Blaufelchen'', Lat.: ''Coregonus wartmanni'')
* [[Sandfelchen]] (German: also ''Weißfelchen'', Lat.: ''Coregonus arenicolus'')
* [[Gangfisch]] (Lat.: ''Coregonus macrophthalmus'')
* [[Lake Constance whitefish]] (German: ''Kilch'', Lat.: ''Coregonus gutturosus'')
* [[Thymallus thymallus|Grayling]] (German: ''Äsche'', Lat.: ''Thymallus thymallus'')
* [[European perch|Perch]] (German: ''Flussbarsch, Kretzer, Barschling,'' Swiss German: ''Egli'', Lat.: ''Perca fluviatilis'')
* [[Common bream|Bream]] (German: ''Brachse'', ''Brasse'', Lat.: ''Abramis brama'')
* [[Northern pike]] (German: ''Hecht'' (Lat.: ''Esox lucius'')
* [[Zander]] (Lat.: ''Sander lucioperca'')
* [[Burbot]] (German: ''Quappe'', ''Trüsche'', Lat.: ''Lota lota'')<ref>Source: Who is Who Bodensee 2010/2011 Südkurier GmbH Medienhaus</ref>
* [[European eel|Eel]] (German: ''Aal'', Lat.: ''Anguilla anguilla'')
* [[European bullhead|Bullhead]] (German: ''Groppe'', Lat.: ''Cottus gobio'')
* [[Tench]] (German: ''Schleie'', Lat.: ''Tinca tinca'')
* [[Wels catfish]] (German: ''Wels'', Lat.: ''Silurus glanis'')
* [[Salmo trutta lacustris|Lake trout]] (German: ''Seeforelle'', Lat.: ''Salmo trutta lacustris'')

The Bodenseefelchen (''Coregonus wartmanni''), which was named after Lake Constance due to the great numbers found there, is often prepared whole or as a fillet, in the style of the miller's wife (''nach Müllerin Art''), in local fish restaurants in a similar way to other trout<ref name="Fische">Themenpark Umwelt des Umweltministeriums Baden-Württemberg – BodenseeWeb: [http://www.themenpark-umwelt.baden-wuerttemberg.de/servlet/is/16094/?path=4422;&partId=0&part=15854 Fische]</ref> It is also often served smoked.

Two [[endemism|endemic]] species are known to have existed only in Lake Constance, the [[Bodensee-Kilch]] (''Coregonus gutturosus'') and [[deepwater char]] (''Salvelinus profundus''). The former is now assumed to be extinct, while the latter was feared extinct for decades until its rediscovery in the 2010s.<ref>Information board at the harbour in [[Ludwigshafen am Bodensee|Ludwigshafen]] about especially prized Lake Constance fish.</ref><ref>{{Cite journal|last1=Doenz|first1=Carmela J.|last2=Seehausen|first2=Ole|date=2020|title=Rediscovery of a presumed extinct species, Salvelinus profundus, after re-oligotrophication|url=https://onlinelibrary.wiley.com/doi/abs/10.1002/ecy.3065|journal=Ecology|language=en|volume=101|issue=8|pages=e03065|doi=10.1002/ecy.3065|pmid=32274790|bibcode=2020Ecol..101E3065D |s2cid=215726746|issn=1939-9170}}</ref>

==== Introduced species ====
For many years [[non-native species]] have settled in the Lake Constance ecosystem and, in some cases, endangered or threatened native flora and fauna. At Lake Constance, non-native species have been increasing annually. Several have been transported from other waterbodies as 'stowaways' on the outside of boats, life jackets, anchor chains or ropes or diving gear.<ref name="Friedrich W. Strub 2016">Friedrich W. Strub: ''Tierische Neuankömmlinge im Bodensee.'' In: Südkurier dated 20 April 2016.</ref> Others have immigrated from the [[Black Sea]] or the [[Danube]] since the opening of the [[Main-Danube Canal]]. Others have been deliberately introduced.<ref name="Anna-Maria Schneider 2015">Anna-Maria Schneider: ''Die heimliche Invasion unter Wasser.'' In: Südkurier date 8 September 2015.</ref>

===== Well-known non-native species =====
Even the [[rainbow trout]] (''Oncorhynchus mykiss'') is not a native fish. It was introduced into Lake Constance around 1880 for economic reasons to enhance the local fauna.<ref name="Eingewanderte Arten">Angela Schneider: ''Gepanzerte Truppe erobert den Bodensee.'' In: ''Südkurier.'' dated 9 October 2010.</ref>

Among the foreign species of animal in Lake Constance are the [[zebra mussel]] (''Dreissena polymorpha'') which, since the 18th century, has spread from the Black Sea region across most of Europe and was carried into Lake Constance between 1960 and 1965. After a huge increase in numbers during the 1980s in the Rhine and large lakes, this species is now in retreat today. The zebra mussel causes problems because, among other things, it blocks water extraction pipes. In addition, the species can be a disaster for domestic shellfish, because it competes for their food.<ref name="Neozoen">Angela Schneider: ''Drei von vielen, die sich bereits im Bodensee etabliert haben.'' In: ''Südkurier.'' dated 9 October 2010.</ref> Today, according to the Institute for Lake Research (''Institut für Seenforschung'', ISF), the zebra mussel is also an important food for overwintering waterfowl. In fact, the number of overwinterers has more than doubled in around 30 years.<ref name="Eingewanderte Arten"/>

The [[killer shrimp]] (''Dikerogammarus villosus'') has spread since 2002 from two sections of shoreline near Hagnau and Immenstaad, over the whole Lake Überlingen (2004), the whole of the Upper Lake (2006) and almost the whole Lake Constance and Rheinsee shore (2007).<ref>''Invasion des Höckerflohkrebses.'' In: ''Südkurier.'' dated 9 October 2010.</ref> As its name implies, it is a voracious burglar of fish larvae and fish eggs.<ref name="Eingewanderte Arten"/>

The most recent example is the little [[opossum shrimp]] (''Limnomysis benedeni''), only six to eleven millimeters long, which was found in 2006 in the Vorarlberg region of Hard, and can now be found almost all over Lake Constance.<ref name="Eingewanderte Arten"/> It comes from the waters around the Black Sea. It was presumably first transported by ships up the Danube before it spread into the Rhine river system and entered Lake Constance. The opossum shrimp, which occurs in many places in shoals of several million in winter, are already an influential link in the food chain in Lake Constance. They consume dead animal and plant material as well as [[phytoplankton]], but are also eaten by fish themselves.<ref name = "Neozoen"/>

Today, in western Lake Constance are found: the North American [[spinycheek crayfish]] (''Orconectes limosus''), which was introduced into European waters in the mid-19th century to increase the yield,<ref name="Eingewanderte Arten" /> occasionally the [[Chinese mitten crab]] (''Eriocheir sinensis''), and in the lake's tributaries, the [[signal crayfish]] (''Pacifastacus leniusulus''). As these species of large crayfish are immune to [[crayfish plague]], but spread the pathogen, they are a great danger to native species such as [[noble crayfish]], [[white-clawed crayfish]] or [[stone crayfish]]. The animals are often undemanding, multiply rapidly and lead predatory lives, thus also posing a threat to various small species of fish.<ref name="Neozoen"/> The ISF has been systematically researching the subject since 2003.<ref name="Eingewanderte Arten"/>

=== Wrecks on the lake bed ===
<!-- {{main article|Shipwrecks in Lake Constance}} -->
After a collision with the ''[[Stadt Zürich (ship, 1855)|Stadt Zürich]]'' in 1864 the [[Shipwreck|wreck]] of the ''[[Jura (ship, 1854)|Jura]]'' has lain on the lake bed at a depth of 45 metres off the Swiss shore. In the early 20th century four ships were sunk in the Obersee after being taken out of service: in 1931 the ''[[Kaiser Wilhelm (ship, 1871)|Baden]]'', formerly the ''Kaiser Wilhelm'', in 1932 the ''Helvetia'', in 1933 the ''Säntis'' and in 1934 the ''Stadt Radolfzell''. The hull of the burnt-out ''[[Friedrichshafen (ship, 1909)|Friedrichshafen]]'' was scuttled in 1944 off the mouth of the [[Argen]] in 100 to 150 metres of water.<ref>Katy Cuko: ''Zwei Schiffswracks im Bodensee gefunden. Verschrottet in 200 Meter Tiefe.'' 20 November 2013.</ref><ref>Janina Raschdorf, Katy Cuko: ''Mindestens 5 Dampfer ruhen im See.'' In: ''Südkurier.'' 5 December 2013.</ref>

== Tourism, leisure and sports ==
The tourism and leisure industry is important for this region. Overnight stays reached 17,56m visitors in 2012 with a turnover of about 1.9bn Euros. The same amount comes from the 70 million visitors that visit Lake Constance each year.<ref>{{Cite web|url=http://www.dwif.de/news-events/news/item/wirtschaftsfaktor-tourismus-bodensee-2014.html|title=DWIF – dwif Wirtschaftsfaktor Tourismus Bodenseeregion|access-date=2017-01-02}}</ref>

[[File:Lake Constance SPOT 1130.jpg|thumb|Eastern part of Upper Lake Constance seen from Spot satellite.]]

This region is known for sightseeing, water-sports, winter-sports like [[Skiing]], summer-sports like [[Swimming (sport)]], [[Sailing]] and recreation. It is also one of the few places where modern [[Zeppelin]] airships operate and 12–14 people can take a trip above the lake around various points of interest.<ref>{{Cite web|url=http://www.bodensee.eu/de/was-erleben/bodensee-highlights/top-erlebnisse/Zeppelinflug_poi223|title=Zeppelinflug : Bodensee Tourismus|website=www.bodensee.eu|access-date=2017-01-02}}</ref>

In cooperation with tourism service providers, tourism organizations and public institutions in Germany, Austria, Switzerland and [[Liechtenstein]], the International Bodensee Tourismus GmbH (IBT GmbH)<ref>{{Cite web|url=http://www.bodensee.eu/de/service/ueber-uns/ibt|title=Internationale Bodensee Tourismus GmbH : Bodensee Tourism – About us|website=www.bodensee.eu|language=de|access-date=2018-02-28}}</ref> is responsible for the tourism marketing of the Lake Constance region.
[[File:Pilgrimage church of Birnau, Lake Constance.jpg|thumb|upright|[[Pilgrimage church]] of Birnau]]

=== Sights and cultural heritage ===
The lake and the region around it have a substantial touristic infrastructure as well as many attractions and points of interests. Important are especially towns like [[Konstanz]], [[Überlingen]], [[Meersburg]], [[Friedrichshafen]], [[Lindau]], [[Romanshorn]], [[Rorschach, Switzerland|Rorschach]] and [[Bregenz]] as they are the big hubs for boating tourism and lake crossing ferries. The main tourism attractions are places like [[Rhine Falls]], one of the three biggest waterfalls in Europe (located near [[Schaffhausen]]), the islands of [[Mainau]], [[Lindau (island)|Lindau]] and [[Reichenau Island|Reichenau]] (UNESCO world heritage), the [[Überlingen|pilgrimage church Birnau]], castles and palaces like [[Salem Abbey]], [[Meersburg Castle]] as well as another UNESCO world heritage site, the [[Pfahlbaumuseum Unteruhldingen]] (German for [[Stilt house]] museum), [[Zeppelin Museum Friedrichshafen]] as well as the [[Church of St. George, Oberzell, Reichenau]] or the ''[[International Rhine Regulation Railway|Rheinschauen]]'' heritage railway.

==== Overlooks ====
High mountain ranges are mainly located near the southeastern shore of the Upper Lake (''Obersee''). The lower [[foothills]] of the [[Appenzell Alps]] in Switzerland are accessible by bus routes and two railway lines: the [[Rorschach–Heiden railway]] between {{rws|Rorschach Hafen}}/{{rws|Rorschach}} near the lake shore and {{rws|Heiden}}, and the [[Rheineck–Walzenhausen mountain railway]] between {{rws|Rheineck}} and {{rws|Walzenhausen}}. Both lines are operated by [[Appenzell Railways]] and part of [[St. Gallen S-Bahn]] and [[Bodensee S-Bahn]], respectively. A popular overlook near [[Heiden, Switzerland|Heiden]] is ''Fünfländerblick'' ({{lit|five countries view}}). In good weather conditions, the lake is also visible from mountain peaks of the [[Alpstein]] massiv. In Austria, the [[Pfänderbahn]], an [[aerial tram]], takes passengers from the [[valley station]] near {{rws|Bregenz Hafen}} to the [[top station]] on [[Pfänder]] mountain ([[Allgäu Alps]]).

The [[Hegau]] region adjacent to Lower Lake Constance (''Untersee'') contains several higher mountains of volcanic origin, many with ruins of fortresses on their tops (e.g. [[Hohenkrähen]], [[Mägdeberg]]). The southernly located of these Hegau volcanoes (e.g. [[Hohentwiel]]) also offer a view over the lakes.

=== Cultural events ===
Lake Constance is the location for the annual [[Bregenzer Festspiele]], a well-known arts festival that, among other venues, takes place on a floating stage in [[Bregenz]]. The operas, plays and concerts performed are usually popular works, e.g. ''[[The Magic Flute]]'' by [[Wolfgang Amadeus Mozart]] or ''[[Rigoletto]]'' by [[Giuseppe Verdi]].<ref>{{Cite web|url=https://bregenzerfestspiele.com/en/company/history|title=History of the Bregenz Festival {{!}} Bregenz Festival|website=bregenzerfestspiele.com|access-date=2020-03-21|archive-date=29 April 2017|archive-url=https://web.archive.org/web/20170429015724/http://bregenzerfestspiele.com/en/company/history|url-status=dead}}</ref>

Since 2001, the ART BODENSEE takes place in [[Dornbirn]]. It is an annual meeting point for the exchange between collectors, artists and art appreciators.<ref>{{Cite web|url=https://artbodensee.messedornbirn.at/themen-aussteller/|title=ART BODENSEE – Messe für zeitgenössische Kunst|website=artbodensee.messedornbirn.at|access-date=2020-03-21}}</ref>

=== Biking ===
Biking around the lake is also possible on the {{convert|261|km|mi|abbr=on}} long trail called "Bodensee-Radweg". It brings its visitors to the most interesting sites and goes around the whole lake. Nevertheless, various shortcuts via ferries allow shorter routes and the trail is suitable for all levels.<ref>{{Cite web|url=http://www.bodensee-radweg.de/|title=Bodensee-Radweg|website=Bodensee-Radweg|language=de-DE|access-date=2017-01-02}}</ref> Note: There is also a trail that goes by the name "Bodensee-Rundweg".<ref>{{Cite web|url=http://www.fernwege.de/d/bodensee/index.html|title=Wandern rund um den Bodensee|website=www.fernwege.de|access-date=2016-12-30}}</ref> This road was intended for pedestrians so biking is sometimes not suitable or allowed.

=== Hiking and pilgrim trails ===
[[File:Wegzeichen - Bodensee-Rundweg.svg|thumb|upright|Sign of the "Lake Constanze circular route"]]
The 260 kilometers long Lake Constance circular route, signposted as "Bodensee Rundwanderweg", leads around Lake Constance through the territories of Germany, Austria and Switzerland. It is mainly intended for hiking; cyclists follow the sometimes slightly different managed Lake Constance cycle path.<ref>{{Cite news|url=http://www.wanderkompass.de/Deutschland/Bodensee-Rundwanderweg.html|title=Bodensee-Rundwanderweg|last=Sven|access-date=2018-02-28|language=de-de}}</ref> The trail can be walked in smaller stages of various lengths and offers nice views of the lake, landscape and wildlife. However, due to industrial settlements, buildings and nature reserves, not all the coastal zones are readily accessible. Furthermore, in the estuary of the rivers, such the [[Leiblach]], [[Bregenzer Ach]], [[Rhine|canalized Rhine]] and [[Alter Rhein|Old Rhine]] ([[Fußach|Fußacher breakthrough]]), considerable distances have to be covered inland to the next bridge or river crossing point. Due to busy riverside roads, the Bodensee-Rundweg sometimes runs as a trail above the lake with some lookout possibilities.

Lake Constance is also a hub for [[Hiking|long-distance hikers]] and pilgrims. It has been a crucial reference point of important [[Pilgrimage|pilgrimage routes]] since ancient times:<ref>{{Cite news|url=https://www.ueberlingen-bodensee.de/Themen/Aktiv/Wandern-am-Bodensee/Der-Jakobsweg|title=Der Jakobsweg (Pilgrimage trail of St. James) {{!}} Ueberlingen near Lake Constance {{!}}|work=Ueberlingen am Bodensee|access-date=2018-02-28|language=de}}</ref>
* Via Beuronensis, a [[Way of St. James]] from the [[Neckar]] region over the [[Swabian Jura|Swabian Alb]]<ref>{{Cite web|url=http://www.via-beuronensis.de|title=Home – Startpunkt|website=www.via-beuronensis.de|language=de|access-date=2018-02-28}}</ref>
* the Upper [[Swabian Jura|Swabian]] pilgrimage-route of St. James, which leads from Upper Swabia to the lake and branches north of the lake both in the direction of [[Nonnenhorn]] and in the direction of [[Meersburg]]
* the Bavarian-Swabian route of St. James, which leads down from the West [[Allgäu]] to the lake
* the Schwabenweg, which ensures the connection to Switzerland to the lake near [[Konstanz]]<ref>{{Cite web|url=https://www.jakobsweg.ch/en/eu/ch/routes/constance-einsiedeln-en/|title=Constance-Einsiedeln (Swabian way)|website=Route of St.James|language=en-US|access-date=2018-02-28}}</ref>

=== Swimming ===
[[Swimming]] in the lake is usually best from mid-June to mid-September. Depending on the weather and exact location, the water temperatures reach {{convert|20| to |27|°C|°F|1}}. Within one day, differences of up to {{convert|3|°C-change}} are possible with appropriate sunlight, so that the lake invites to swim, especially on warm summer evenings.<ref>{{Cite web|url=http://www.wetter-kressbronn.de/wassertemperatur-bodensee.html|title=Weather-station in Kressbronn (in German)|website=www.wetter-kressbronn.de|language=en|access-date=2018-02-28}}</ref>

=== Diving ===
[[File:Teufelstisch-Bodensee-01.jpeg|thumb|Diving spot "devils table" at Lake Constanze]]
[[Underwater diving|Diving]] in Lake Constance is considered attractive and challenging. Most of the diving areas are located in the northern part of the lake ([[Überlingen]], [[Bodman-Ludwigshafen]], [[Marienschlucht]] and others), a few also in the south.<ref>{{Cite web|url=https://www.tauchakademiebodensee.de/tauchplatze-im-bodensee/|archive-url=https://web.archive.org/web/20180619164757/https://www.tauchakademiebodensee.de/tauchplatze-im-bodensee/|archive-date=19 June 2018|url-status=dead|title=Diving Spots at Lake Constanze (in German)|website=www.tauchakademiebodensee.de|language=de-DE|access-date=2018-02-28}}</ref> The areas should be dived exclusively by experienced divers under the guidance of one of the local diving schools or a seasoned diver. Diving at some spots like the devils table ("Teufelstisch") called rock needle in the lake in front of the Marienschlucht, is only allowed after approval by the district office Konstanz.

A famous [[Fresh water|freshwater]] [[Wreck diving|wreck]] in Europe is the [[paddle steamer]] Jura, which lies in front of [[Bottighofen]] at a depth of  {{convert|39|m|ft|abbr=off}}. The [[canton of Thurgau]], the office for [[archaeology]] in Frauenfeld, has placed the Jura under protection as an underwater industrial monument.<ref>{{Cite news|url=http://tauchboot-bodensee.ch/jura-tauchen-bootsfahrten/|title=Wrack der Jura – Tauchen vom Boot im Bodensee|work=Tauchen vom Boot im Bodensee|access-date=2018-02-28|language=de-DE}}</ref>

For all divers, the water in Lake Constance—even in summer—is already below {{convert|10|°C|°F}} from a depth of {{convert|10|m|ft|sigfig=3}} which requires suitable [[Diving regulator|cold-water regulators]] that do not freeze at such temperatures.

=== Boating, recreational boating ===
[[File:Rundum05 047.jpg|thumb|"Rund-um" (All-Around) Regatta next to Lindau]]
Pleasure boating is important. At the beginning of 2011, 57,875 amusement vehicles were registered for Lake Constance.<ref>{{Cite web|url=http://www.vorarlberg.at/vorarlberg/wirtschaft_verkehr/wirtschaft/maschinenbauundelektrotec/weitereinformationen/maschinenwesen/schifffahrt/bodensee-schiffsstatistik.htm|title=Land Vorarlberg – Bodensee-Schiffsstatistik 2011|website=www.vorarlberg.at|language=de|access-date=2018-02-28|archive-url=https://web.archive.org/web/20160304210320/http://www.vorarlberg.at/vorarlberg/wirtschaft_verkehr/wirtschaft/maschinenbauundelektrotec/weitereinformationen/maschinenwesen/schifffahrt/bodensee-schiffsstatistik.htm|archive-date=4 March 2016|url-status=dead}}</ref>

The legal basis for all shipping on the lake is the ordinance on shipping on Lake Constance, or "Bodensee-Schifffahrtsordnung". It is monitored on Lake Constance and on the Upper Rhine by the German, Swiss and Austrian Water Police, the "Seepolizei".

All boats must be registered, and boat drivers must hold a "Bodenseeschifferpatent" (authorization to drive a patented vehicle on Lake Constance). It is issued in Germany by the shipping offices of the district of Constance, the Lake Constance district, and the district of [[Lindau]]; in Switzerland by the cantonal authorities; and in Austria by the District Commission [[Bregenz]]. For pleasure boaters short-term guest licenses are possible (for the categories A for [[motorboat]]s over 4.4 kW and D for [[sailboat]]s over 12 m<sup>2</sup> sail area).

'''Boating events'''
* Since 1979, every year to the [[assumption of Mary]], Europe's largest ship procession is held on Lake Constance.<ref>{{Cite web|url=https://www.gebetsstaette.de/gebetsstaette-wigratzbad/schiffsprozession/|title=Schiffsprozession: Gebetsstätte Wigratzbad|website=www.gebetsstaette.de|language=de|access-date=2018-02-28}}</ref> 
* Every year (early summer) the spectacular all-around ("Rund-um") [[Regatta]] from Lindau to [[Lindau]] via [[Meersburg]], [[Überlingen]], [[Romanshorn]] is organized.<ref>{{Cite news|url=http://www.lindau.de/en/dossier/rund-um-regatta|title=Sailing Days "Rund Um" in Lindau at Lake Constance|work=Lindau Tourismus|access-date=2018-02-28|language=en-US}}</ref> 
* Since 2009, the annual [[List of water sports|water sports]] and sailing festival "International Lake Constanze week", a joint sports event takes place in Konstanz. 
* In Friedrichshafen, one of the most important water sports fairs in Europe, the Interboot, takes place annually.<ref>{{Cite web|url=http://www.interboot.com/ib-en/index.php|title=INTERBOOT|website=www.interboot.com|language=en|access-date=2018-02-28}}</ref>

=={{anchor|settlements}}Settlements on the lake==
[[File:Hohentwiel04.JPG|thumb|The steamboat, ''Hohentwiel'']]
[[File:Austria-Bregenz-Pfaender.jpg|thumb|View from the Pfänder hill of Bregenz and the lake (with Lindau in the background)]]
[[File:Hegne und Reichenau.jpg|thumb|[[Reichenau island|Reichenau]] seen from the German shore]]
[[File:Bodenmeer vanaf Lindau foto2 2009-06-01 09.44.JPG|thumb|Lake Constance from Lindau]]
[[File:Bodensee.jpg|thumb|Twilight near Arbon]]
[[File:Untersee Berlingen.jpg|thumb|The Lower Lake (''Untersee'')]]
[[File:Dingelsdorf Schiffsanlegestelle.jpg|thumb|Dingelsdorf shipping [[pier]]]]

===Austria===

*[[Hard, Austria|Hard]]
*[[Hörbranz]]
*[[Bregenz]]
*[[Lochau]]
*[[Höchst, Austria|Höchst]]
*[[Fussach]]
*[[Gaissau]]

===Germany===
From the entry of the Rhine, on the northern or right shore:
*On the Upper Lake (''Obersee'')
**[[Lindau, Lake Constance|Lindau]] (in [[Bavaria]])
**[[Wasserburg am Bodensee|Wasserburg]]
**[[Nonnenhorn]]
**[[Kressbronn am Bodensee|Kressbronn]] (in [[Baden-Württemberg]])
**[[Langenargen]]
**[[Eriskirch]]
**[[Friedrichshafen]]
**[[Immenstaad]]
**[[Hagnau am Bodensee|Hagnau]]
**[[Stetten, Bodenseekreis|Stetten]]
**[[Meersburg]]
**[[Uhldingen-Mühlhofen]] (on the ''Überlinger See'')
**[[Überlingen]]
**[[Sipplingen]]
**[[Bodman-Ludwigshafen|Ludwigshafen]]
**[[Bodman-Ludwigshafen|Bodman]]
*[[Konstanz]] with suburbs
**[[Wallhausen (Bodensee)|Wallhausen]]
**[[Dingelsdorf]]
**[[Litzelstetten]]
*On the Lower Lake (''Untersee'')
**[[Reichenau Island|Reichenau]] (including the island with same name)
**[[Allensbach]] (on the [[Gnadensee]])
**[[Radolfzell am Bodensee]] (on the [[Zellersee (Lake Constance)|''Zeller See'']])
**[[Moos, Baden-Württemberg|Moos]]
**[[Gaienhofen]]
**[[Öhningen]]

===Switzerland===
From the entry of the Rhine, on the southern or left shore:
*On the Upper Lake (''Obersee'')
**[[Altenrhein]], [[Canton of St. Gallen|St. Gallen]]
**[[Staad]], [[Canton of St. Gallen|St. Gallen]]
**[[Rorschach, St. Gallen]]
**[[Goldach]], [[Canton of St. Gallen|St. Gallen]]
**[[Horn, Switzerland|Horn]], [[Canton of Thurgau|Thurgau]]
**[[Steinach, St. Gallen|Steinach]], [[Canton of St. Gallen|St. Gallen]]
**[[Arbon, Switzerland|Arbon]], [[Canton of Thurgau|Thurgau]] (as all the following)
**[[Frasnacht]]
**[[Egnach]]
**[[Salmsach]]
**[[Romanshorn]]
**[[Uttwil]]
**[[Kesswil]]
**[[Güttingen]]
**[[Altnau]]
**[[Landschlacht]]
**[[Münsterlingen]]
**[[Scherzingen]]
**[[Bottighofen]]
**[[Kreuzlingen]] (and [[Konstanz]], Germany)
*On the Seerhein
**[[Gottlieben]]
*On the Lower Lake (''Untersee'')
**[[Triboltingen]]
**[[Ermatingen]]
**[[Mannenbach]]
**[[Eschlibach]]
**[[Berlingen, Switzerland|Berlingen]]
**[[Steckborn]]
**[[Mammern]]
**[[Eschenz]]
**[[Stein am Rhein]], [[Canton of Schaffhausen|Schaffhausen]]

== Fishing ==
The lake was frozen in the years 1077 (?), 1326 (partial), 1378 (partial), 1435, 1465 (partial), 1477 (partial), 1491 (partial?), 1517 (partial), 1571 (partial), 1573, 1600 (partial), 1684, 1695, 1709 (partial), 1795, 1830, 1880 (partial), and 1963.

About {{convert|1000|t|ST|lk=on}} of fish were caught by 150 professional fishermen in 2001 which was below the previous ten-year average of {{convert|1200|t|ST}} per year. The Lake Constance [[Brown trout|trout]] (''Salmo trutta'') was almost extinct in the 1980s due to pollution, but thanks to protective measures they have made a significant return. Lake Constance is the home of the critically endangered species of trout ''[[Salvelinus profundus]]'',<ref>[http://www.swissinfo.ch/eng/deep-water-char_-extinct--fish-found-in-lake-constance/42425340 ‘Extinct’ fish found in Lake Constance]</ref> and formerly also the now [[extinct]] Lake Constance whitefish (''[[Coregonus gutturosus]]'').<ref>{{Cite web |url=http://www.bfn.de/0322_rote-liste-wirbeltiere+M52087573ab0.html |title=Red List – Volume 1: Vertebrates (2009) – General assessment for the vertebrate groups |access-date=2012-12-28 |archive-url=https://web.archive.org/web/20130623053516/http://www.bfn.de/0322_rote-liste-wirbeltiere+M52087573ab0.html |archive-date=2013-06-23 |url-status=dead }}</ref>

==See also==
*[[Überlingen mid-air collision]]
*[[Württembergischer Yacht Club]]
*''Lake Constance'' is also the title of a track from [[Mike Oldfield]]'s ''[[The Millennium Bell]]'' album
* [[Peter Handke]]'s play, Ride Across lake Constance, was written in 1971.

==Notes and references==
===Notes===
===References===
{{reflist}}

==Further reading==
*{{Citation |last=Zimmermann |first=Rolf |date=2004 |title=A Look at Lake Constance |location=Konstanz, Germany |publisher=Stadler Verlagsgesellschaft |isbn=3-7977-0507-7}} (Pictures and texts of the cities around Lake Constance).

==External links==
{{Commons category|Lake Constance}}
{{Wikivoyage}}
* {{Cite EB1911|wstitle= Constance, Lake of | volume= 6 |last= Coolidge |first= William Augustus Brevoort |author-link= W. A. B. Coolidge|  page = 986 |short= 1}}
*{{HDS|8655|author=Karl Heinz Burmeister|date=11 June 2007}}

*{{Lakes Germany 2004|Bodensee|Baden-Württemberg|page=4}}
*[http://www.bodensee-hochwasser.info Bodensee-Hochwasser] {{in lang|de}} waterlevels
*[http://www.bodenseekonferenz.org Internationale Bodenseekonferenz]
*[https://web.archive.org/web/20110802211515/http://www.statistik-bodensee.org/index.php/home.html Regio Bodensee Statistics]
*[https://www.alemannische-seiten.de/bilder/bodensee/ Lake Constance: pictures] {{in lang|de}}
*[http://english.konstanz-magazin.de/picture_galleries.php Photos of Lake Constance]
*[http://www.ppl.nl/index.php?option=com_wrapper&view=wrapper&Itemid=82 Bibliography on Water Resources and International Law] Peace Palace Library
*[http://www.grenzraumsee.uni-tuebingen.de/ GrenzRaumSee: A project from the ''Ludwig-Uhland-Institut für Empirische Kulturwissenschaft'' (Ludwig-Uhland-Department of European Ethnology / Empirical Cultural Science) of the University of Tübingen ] {{Webarchive|url=https://web.archive.org/web/20201221113658/http://www.grenzraumsee.uni-tuebingen.de/ |date=21 December 2020 }}
*{{usurped|1=[https://web.archive.org/web/20050216002700/http://www.worldlakes.org/uploads/constance_30sep04.pdf Lake Constance/Bodensee Lessons learned managing the lake]}}
*[http://www.bodensee-gastgeber.de/ Lake Constance Accommodation]
*[http://www.gastgeberverzeichnis-bodensee.com/ Tourist Information Lake Constance]
*[https://fishing-app.gpsnauticalcharts.com/i-boating-fishing-web-app/fishing-marine-charts-navigation.html?type=lake-constance-enc-chart#10.08/47.5843/9.4094 Lake Constance ENC Chart]

{{Lakes of Switzerland}}
{{Lake Constance|state=collapsed}}
{{Authority control}}

{{DEFAULTSORT:Constance}}
[[Category:Lake Constance| ]]
[[Category:Lakes of Baden-Württemberg]]
[[Category:Lakes of Bavaria]]
[[Category:Lakes of Switzerland]]
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[[Category:Lakes of Thurgau]]
[[Category:Lakes of the canton of St. Gallen]]
[[Category:Lakes of Vorarlberg]]
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[[Category:International lakes of Europe]]
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[[Category:Border tripoints]]
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