Editing Rhine (section)

=== Lake Constance ===
[[File:Bodensee satellit.jpg|thumb|right|upright=1.5|Satellite image. In the center and on the right (i.e. to the east) the larger part of Lake Constance, called the ''[[Obersee (Lake Constance)|Obersee]]'', is visible, and it includes, in the lower right, the [[River Delta|delta]] of the [[Alpine Rhine]]. The northwesterly "finger" (on the top left) is ''Lake Überlingen'', containing the island of [[Mainau]]. Below Lake Überlingen (also in the west) is the smaller ''[[Untersee (Lake Constance)|Untersee]]'', containing [[Reichenau Island]]. The Obersee and Untersee are connected by the four kilometers long [[Seerhein]]. On the left the [[High Rhine]] can be seen.]]
{{Main|Lake Constance}}
Lake Constance consists of three bodies of water: the [[Obersee (Lake Constance)|Obersee]] ("upper lake"), the [[Untersee (Lake Constance)|Untersee]] ("lower lake"), and a connecting stretch of the Rhine, called the Seerhein ("Lake Rhine"). The lake is situated in Germany, Switzerland and [[Austria]] near the Alps. Specifically, its shorelines lie in the German states of [[Bavaria]] and [[Baden-Württemberg]], the Austrian state of [[Vorarlberg]], and the Swiss cantons of [[Thurgau]] and [[St. Gallen]]. The Rhine flows into it from the south following the Swiss-Austrian border. It is located at approximately {{coord|47|39|N|9|19|E|type:waterbody}}.

==== Obersee ====
{{Main|Obersee (Lake Constance)}}
The flow of cold, grey mountain water continues for some distance into the lake. The cold water flows near the surface and at first does not mix with the warmer, green waters of Upper Lake. But then, at the so-called ''Rheinbrech'', the Rhine water abruptly falls into the depths because of the greater density of cold water. The flow reappears on the surface at the northern (German) shore of the lake, off the island of [[Lindau (Bodensee)|Lindau]]. The water then follows the northern shore until [[Hagnau am Bodensee]]. A small fraction of the flow is diverted off the island of [[Mainau]] into Lake Überlingen. Most of the water flows via the ''Constance hopper'' into the ''Rheinrinne'' ("Rhine Gutter") and Seerhein. Depending on the water level, this flow of the Rhine water is clearly visible along the entire length of the lake.

The Rhine carries very large amounts of debris into the lake{{snd}}over {{convert|3000000|m3|spell=in|abbr=out|sp=us}} annually.<ref>{{cite web |last1=Bergmeister |first1=U. |last2=Kalt |first2=L. |title=Geschiebeführung |trans-title=Conveyance of bedload |url=http://www.rheinregulierung.at/kms/cms/kms.php?id=21&str_id=22&det_back=1 |publisher=Internationale Rheinregulierung |archive-url=https://web.archive.org/web/20120322191124/http://www.rheinregulierung.at/kms/cms/kms.php?id=21&str_id=22&det_back=1 |archive-date=22 March 2012 |location=Lustenau |language=de |url-status=dead}}</ref> In the mouth region, it is therefore necessary to permanently remove gravel by dredging. The large [[sediment]] loads are partly due to the extensive [[land improvements]] upstream.

Three countries border the Obersee, namely Switzerland in the south, Austria in the southeast and the German states of [[Bavaria]] in the northeast and [[Baden-Württemberg]] in the north and northwest.

==== Seerhein ====
{{Main|Seerhein}}
[[File:Konstanz Blick vom Münsterturm.jpg|thumb|Distance markers along the Rhine indicate distances from this bridge in [[Konstanz]]]]
[[File:Rheinkilometer Loreley.JPG|thumb|right|upright|The 555&nbsp;km marker downstream from the [[Lorelei]]]]
The [[Seerhein]] is only {{Convert|4|km|mi|sp=us}} long. It connects the [[Obersee (Lake Constance)|Obersee]] with the 30&nbsp;cm lower [[Untersee (Lake Constance)|Untersee]]. Distance markers along the Rhine measure the distance from the bridge in the old city center of Konstanz.

For most of its length, the Seerhein forms the border between Germany and Switzerland. The exception is the old city center of Konstanz, on the Swiss side of the river.

The Seerhein emerged in the last thousands of years, when erosion caused the lake level to be lowered by about 10 meters. Previously, the two lakes formed a single lake, as the name still suggests.

==== Untersee ====
{{Main|Untersee (Lake Constance)}}
Like in the Obersee, the flow the Rhine can be traced in the Untersee. Here, too, the river water is hardly mixed with the lake water. The northern parts of the Untersee (Lake Zell and Gnadensee) remain virtually unaffected by the flow. The river traverses the southern, which, in isolation, is sometimes called ''Rhinesee'' ("Lake Rhine"). The ''[[Schweizerische Schifffahrtsgesellschaft Untersee und Rhein]]'' (URh) offers regular boat trips on Untersee.

Besides the ''Seerhein'', the [[Radolfzeller Aach]] is the main tributary of ''Untersee''. It adds large amounts of water from the [[Danube]] system to the ''Untersee'' via the [[Danube Sinkhole]].

Reichenau Island was formed at the same time as the Seerhein, when the water level fell to its current level.

Lake Untersee is part of the [[Germany–Switzerland border|border between Switzerland and Germany]], with Germany on the north bank and Switzerland on the south, except both sides are Swiss in [[Stein am Rhein]], where the [[High Rhine]] flows out of the lake.