Rhine

The Rhine is one of the major rivers of Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Swiss-Austrian border. From Lake Constance downstream, it forms part of the Swiss-German border. After that the Rhine defines much of the Franco-German border. It then flows in a mostly northerly direction through the German Rhineland. Finally, the Rhine turns to flow predominantly west to enter the Netherlands, eventually emptying into the North Sea. It drains an area of 185,000 km².
Its name derives from the Gaulish Rēnos. There are two German states named after the river, North Rhine-Westphalia and Rhineland-Palatinate, in addition to several districts. The departments of Bas-Rhin and Haut-Rhin in Alsace are also named after the river. Some adjacent towns are named after it, such as Rheinau, Stein am Rhein, Rheineck, Rheinfelden and Rheinfelden.
The International Commission for the Hydrology of the Rhine Basin and EUWID contend that the river could experience a massive decrease in volume, or even dry up completely in case of drought, within the next 30 to 80 years, as a result of the climate crisis.
The Rhine is the second-longest river in Central and Western Europe, at about, with an average discharge of about. It also contains the most powerful waterfall in Europe, the Rhine Falls.
The Rhine and the Danube comprised much of the Roman Empire's northern inland boundary, and the Rhine has been a vital navigable waterway bringing trade and goods deep inland since those days. The various castles and defenses built along it attest to its prominence as a waterway in the Holy Roman Empire. Among the largest and most important cities on the Rhine are Cologne, Rotterdam, Düsseldorf, Duisburg, Strasbourg, Arnhem, and Basel.

Name

The variants of the name of the Rhine in modern languages are all derived from the Gaulish name Rēnos, which was adapted in Roman-era geography as Latin Rhenus, and as Greek Ῥῆνος.
The spelling with Rh- in English Rhine as well as in German Rhein and French Rhin is due to the influence of Greek orthography, while the vocalization -i- is due to the Proto-Germanic adoption of the Gaulish name as, via Old Frankish giving Old English Rín, Old High German Rīn, early Middle Dutch Rijn.
The modern German diphthong Rhein Rein, Rain is a Central German development of the early modern period, with the Alemannic name Rhi keeping the older vocalism. In Alemannic, the deletion of the ending -n in pausa is a recent development; the form Rhin is largely preserved in Lucernese dialects. has Rhing in Ripuarian is diphthongized, as is Rhei, Rhoi in Palatine. While Spanish has adopted the Germanic vocalism Rin-, Italian, Occitan, and Portuguese have retained the Latin Ren-.
The Gaulish name Rēnos belongs to a class of river names built from the Proto-Indo-European root *rei- "to move, flow, run", also found in other names such as the Reno in Italy.
The grammatical gender of the Celtic name is masculine, and the name remains masculine in German, Dutch, French, Spanish and Italian. The Old English river name was variously inflected as masculine or feminine; and its Old Icelandic adoption was inflected as feminine.

Geography

The length of the Rhine is conventionally measured in "Rhine-kilometers", a scale introduced in 1939 that runs from the 0 km datum at Old Rhine Bridge in the city of Konstanz, at the western end of Lake Constance, to the Hook of Holland at 1,036.20 km.
The river is significantly shortened from its natural course due to a number of canal projects completed in the 19th and 20th centuries. The "total length of the Rhine", to the inclusion of Lake Constance and the Alpine Rhine is more difficult to measure objectively; it was cited as by the Dutch Rijkswaterstaat in 2010.
Its course is conventionally divided as follows:

Length	Section	Avg. discharge	Elevation	Left tributaries	Right tributaries
76 km	The various sources and headwaters forming the Anterior and Posterior Rhine within Grisons, Switzerland	116 m³/s	584 m	Aua Russein, Schmuèr	Rein da Tuma, Rein da Curnera, Rein da Medel, Rein da Sumvitg, Glogn, Rabiusa, Rein Posteriur/Hinterrhein
90 km	The Alpine Rhine running through the Grisonian and St. Gall Rhine Valley	245 m³/s	400 m	Tamina, Saar	Plessur, Landquart, Liechtenstein inland canal, Ill, Frutz
c. 60 km	Lake Constance, including the short channel called Seerhein at Konstanz, connecting Obersee and Untersee	364 m³/s	395 m	Alter Rhein, Goldach, Aach	Dornbirner Ach, Bregenzer Ach, Leiblach, Argen, Schussen, Rotach, Brunnisach, Lipbach, Seefelder Aach, Stockacher Aach, Radolfzeller Aach
c. 150 km	The High Rhine from the exit of Lake Constance to Basel, forming a substantial part of the German-Swiss border	1,089 m³/s	246 m	Thur, Töss, Glatt, Aare, Sissle. Möhlinbach, Ergolz, Birs	Biber, Durach, Wutach, Alb, Murg, Wehra
362 km	The Upper Rhine from Basel to Bingen forming the Upper Rhine Plain and in its upper course the Franco-German border		79 m	Birsig, Ill, Moder, Lauter, Nahe	Wiese, Kander, Elz, Kinzig, Rench, Acher, Murg, Alb, Pfinz, Neckar, Main
159 km	The Middle Rhine between Bingen and either Bonn or Cologne is entirely within Germany, passing the Rhine Gorge;		45 m	Moselle, Nette, Ahr	Lahn, Wied, Sieg
177 km	The Lower Rhine or Niederrhein downstream of Bonn, passing the Lower Rhine region of North Rhine-Westphalia		11 m	Erft	Wupper, Düssel, Ruhr, Emscher, Lippe
c. 50 km	The Nether Rhine or Nederrijn	2,900 m³/s	0 m	Meuse	Oude IJssel, Berkel

Headwaters and sources

Anterior Rhine and Posterior Rhine

The source of the river is generally considered north of Lai da Tuma/Tomasee on Rein Anteriur/Vorderrhein, although its southern tributary Rein da Medel is actually longer before its confluence with the Anterior Rhine near Disentis.
The Anterior Rhine arises from numerous source streams in the upper Surselva and flows in an easterly direction. One source is Lai da Tuma with the Rein da Tuma, which is usually indicated as source of the Rhine, flowing through it.
Into it flow tributaries from the south, some longer, some equal in length, such as the Rein da Medel, the Rein da Maighels, and the Rein da Curnera. The Cadlimo Valley in the canton of Ticino is drained by the Reno di Medel, which crosses the geomorphologic Alpine main ridge from the south. All streams in the source area are partially, sometimes completely, captured and sent to storage reservoirs for the local hydro-electric power plants.
The culminating point of the Anterior Rhine's drainage basin is the Piz Russein of the Tödi massif of the Glarus Alps at above sea level. It starts with the creek Aua da Russein.
In its lower course, the Anterior Rhine flows through a gorge named Ruinaulta. The whole stretch of the Anterior Rhine to the Alpine Rhine confluence next to Reichenau in Tamins is accompanied by a long-distance hiking trail called Senda Sursilvana.
The Posterior Rhine flows first east-northeast, then north. It flows through the three valleys named Rheinwald, Schams and Domleschg-Heinzenberg. The valleys are separated by the Rofla Gorge and Viamala Gorge. Its sources are located in the Adula Alps.
The Avers Rhine joins from the south. One of its headwaters, the Reno di Lei, is partially located in Italy.
Near Sils the Posterior Rhine is joined by the Albula, from the east, from the Albula Pass region. The Albula draws its water mainly from the Landwasser with the Dischmabach as the largest source stream, but almost as much from the Gelgia, which comes down from the Julier Pass.
Numerous larger and smaller tributary rivers bear the name of the Rhine or equivalent in various Romansh idioms, including Rein or Ragn, including:

Anterior Rhine area: Rein Anteriur/Vorderrhein, Rein da Medel, Rein da Tuma, Rein da Curnera, Rein da Maighels, Rein da Cristallina, Rein da Nalps, Rein da Plattas, Rein da Sumvitg, Rein da Vigliuts, Valser Rhine
Posterior Rhine basin: Rein Posteriur/Hinterrhein, Reno di Lei, Madrischer Rhein, Avers Rhine, Jufer Rhein
Albula-Landwasser area: In the Dischma valley, near Davos, far east of the Rhine, there's a place called Am Rin. A tributary of the Dischma is called Riner Tälli. Nearby, on the other side of the Sertig, is the Rinerhorn.
Alpine Rhine

Next to Reichenau in Tamins the Anterior Rhine and the Posterior Rhine join and form the Alpine Rhine. The river makes a distinctive turn to the north near Chur. This section is nearly 86 km long, and descends from a height of 599 meters to 396 meters. It flows through a wide glacial Alpine valley known as the Rhine Valley. Near Sargan a natural dam, only a few meters high, prevents it from flowing into the open Sztal valley and then through Lake Walen and Lake Zurich into the Aare. The Alpine Rhine begins in the westernmost part of the Swiss canton of Graubünden, and later forms the border between Switzerland to the west and Liechtenstein and later Austria to the east.
As an effect of human work, it empties into Lake Constance on Austrian territory and not on the border that follows its old natural river bed called Alter Rhein.
The mouth of the Rhine into Lake Constance forms an inland delta. The delta is delimited in the west by the Alter Rhein and in the east by the modern canalized section of the Alpine Rhine. Most of the delta is a nature reserve and bird sanctuary. It includes the Austrian towns of Gaißau, Höchst and Fußach. The natural Rhine originally branched into at least two arms and formed small islands by precipitating sediments. In the local Alemannic dialect, the singular is pronounced "Isel" and this is also the local pronunciation of Esel. Many local fields have an official name containing this element.
A regulation of the Rhine was called for, with an upper canal near Diepoldsau and a lower canal at Fußach, in order to counteract the constant flooding and strong sedimentation in the western Rhine Delta. The Dornbirner Ach had to be diverted, too, and it now flows parallel to the canalized Rhine into the lake. Its water has a darker color than the Rhine; the latter's lighter suspended load comes from higher up the mountains. It is expected that the continuous input of sediment into the lake will silt up the lake. This has already happened to the former Lake Tuggenersee.
The cut-off Old Rhine at first formed a swamp landscape. Later an artificial ditch of about two km was dug. It was made navigable to the Swiss town of Rheineck.