The Rhine flows from Grisons in the eastern Swiss Alps to the North Sea coast in the Netherlands and is one of the longest and most important rivers in Europe, at about , with an average discharge of more than .

The Rhine and the Danube formed most of the northern inland frontier of the Roman Empire and, since those days, the Rhine has been a vital and navigable waterway carrying trade and goods deep inland. It has also served as a defensive feature and has been the basis for regional and international borders. The many castles and prehistoric fortifications along the Rhine testify to its importance as a waterway. River traffic could be stopped at these locations, usually for the purpose of collecting tolls, by the state that controlled that portion of the river.

Etymology and names

The English name of the Rhine derives from Old English ''Rīn'', which descends from Proto-Germanic *''Rīnaz''. This is also the source of the name in the other Germanic languages such as Dutch ''Rijn'' (formerly also ''Rhijn''), German ''Rhein'', Romansh ''Rain'' (via German) and also French ''Rhin'' and Spanish ''Rin'', which came into the language through Old Frankish. This in turn derives from Indo-European *''Reynos'', from the root *''rey-'' "to flow, to run", which is also the root of words like ''river'' and ''run''. The Celtic/Gaulish name for the Rhine is ''Rēnos'', which derives from the same Indo-European source as the Germanic name. It is also found in other names such as the Reno River in Italy, which got its name from Gaulish. The Latin name ''Rhēnus'' and Ancient Greek ''Ρήνος'' (''Rhēnos'') both derive from the Celtic word, and not from Indo-European directly, because they both share the change from -''ei''- to -''ē''-, which is characteristic of the Celtic languages but not of Latin or Greek (the Latin name would have been *''Rīnus'' otherwise).

The name is spelled with -h- in many languages today, but judging from earlier attestations of the name that lack the -h- (such as in Old English), this is not an etymological spelling. Instead, it is probably based on the Latin transliteration of the Greek form of the name, ''Rhenos'', seen also in ''rheos'', stream, and ''rhein'', to flow. The Latin spelling was probably also taken from Greek, although the name of the river may have existed in Latin before that. Its modern descendant is found in Italian ''Reno'' (also the name of a river in Italy, as mentioned above).

Geography

Length

Until 1932 the generally accepted length of the Rhine was . In 1932, however, the German encyclopedia ''Knaurs Lexikon'' stated the length as , presumably a typographical transposition error. After this number was placed into the authoritative ''Brockhaus Enzyklopädie,'' it became generally accepted and found its way into numerous textbooks and official publications. The error was discovered in 2010, and the Dutch ''Rijkswaterstaat'' confirms the length as .

Switzerland, Liechtenstein, Austria, Germany

The Rhine is called that name from the confluence of the ''Vorderrhein'' and ''Hinterrhein'', near Reichenau in the canton of Grisons.

The initial source of the river is known to all people and pupils in Grisons and Switzerland as lying north of ''Lai da Tuma'' (Tomasee) on Vorderrhein, although some people nowadays do claim that its southern tributary ''Rein da Medel'' is actually longer before its confluence with the Vorderrhein near Disentis. :The ''Vorderrhein'', or Anterior Rhine, springs from ''Lai da Tuma'' (Tomasee), near the Oberalp Pass and passes the impressive ''Ruinaulta'' formed by the largest visible rock slide in the alps, the Flims Rockslide. A multiday trekking route is signposted along the young Rhine called ''Senda Sursilvana''. :The ''Hinterrhein'', or Posterior Rhine, starts from the Paradies Glacier, near the Rheinwaldhorn. One of its tributaries, the ''Reno di Lei'', drains the ''Valle di Lei'' on politically Italian territory. After three main valleys separated by the two gorges, Roflaschlucht and Viamala, it reaches Reichenau.

From Reichenau, the Rhine flows east as the ''Alpenrhein'' or "Alpine Rhine", passes Chur turning north to form another 20 km further north the border between Liechtenstein and then Austria, on the east side and Canton of St. Gallen of Switzerland, on the west side. 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. It emerges from Lake Constance, flows generally westward, as the ''Hochrhein'', passes the Rhine Falls, and is joined by the river Aar. The Aar more than doubles the Rhine's water discharge, to an average of nearly . The Aar also contains the waters from the summit of Finsteraarhorn, the highest point of the Rhine basin. The Rhine roughly forms the boundary with Germany from Lake Constance with the exceptions of the canton of Schaffhausen and a part of the canton of Zürich, until it turns north at the so-called Rhine knee at Basel, leaving Switzerland.

Germany, France

The Rhine is the longest river in Germany. It is here that the Rhine encounters some of its main tributaries, such as the Neckar, the Main and, later, the Moselle, which contributes an average discharge of more than . Northeastern France drains to the Rhine via the Moselle; smaller rivers drain the Vosges and Jura Mountains, uplands. Most of Luxembourg and a very small part of Belgium also drain to the Rhine via the Moselle. As it approaches the Dutch border, the Rhine has an annual mean discharge of and an average width of .

Between Bingen and Bonn, the Middle Rhine flows through the Rhine Gorge, a formation which was created by erosion. The rate of erosion equalled the uplift in the region, such that the river was left at about its original level while the surrounding lands raised. The gorge is quite deep and is the stretch of the river which is known for its many castles and vineyards. It is a UNESCO World Heritage Site (2002) and known as "the Romantic Rhine", with more than 40 castles and fortresses from the Middle Ages and many quaint and lovely country villages.

Until the early 1980s, industry was a major source of water pollution. Although many plants and factories can be found along the Rhine up into Switzerland, it is along the Lower Rhine in the Ruhr Area, that the bulk of them are concentrated, as the river passes the major cities of Cologne, Düsseldorf and Duisburg. Duisburg is the home of Europe's largest inland port and functions as a hub to the sea ports of Rotterdam, Antwerp and Amsterdam. The Ruhr, which joins the Rhine in Duisburg, is nowadays a clean river, thanks to a combination of stricter environmental controls, a transition from heavy industry to light industry and cleanup measures, such as the reforestation of Slag and brownfields. The Ruhr currently provides the region with drinking water. It contributes to the Rhine. Other rivers in the Ruhr Area, above all, the Emscher, still carry a considerable degree of pollution.

Netherlands

The Dutch word for "Rhine" is "Rijn". The Rhine turns west and enters the Netherlands, where, together with the rivers Meuse and Scheldt, it forms the extensive Rhine-Meuse-Scheldt delta, one of the larger river deltas in western Europe. Crossing the border into the Netherlands at Spijk, close to Nijmegen and Arnhem, the Rhine is at its widest, although the river then splits into three main distributaries: the Waal River, Nederrijn ("Lower Rhine") and IJssel.

From here, the situation becomes more complicated, as the Dutch name ''Rijn'' no longer coincides with the main flow of water. Two thirds of the Rhine water flows farther west, through the Waal and then, via the Merwede and Nieuwe Merwede (De Biesbosch), merging with the Meuse, through the Hollands Diep and Haringvliet estuaries, into the North Sea. The Beneden Merwede branches off, near Hardinxveld-Giessendam and continues as the Noord, to join the Lek, near the village of Kinderdijk, to form the Nieuwe Maas; then flows past Rotterdam and continues via Het Scheur and the Nieuwe Waterweg, to the North Sea. The Oude Maas branches off, near Dordrecht, farther down rejoining the Nieuwe Maas to form Het Scheur.

The other third portion of the water flows through the Pannerdens Kanaal and redistributes in the IJssel and Nederrijn. The IJssel branch carries one ninth of the water volume north, into the IJsselmeer (a former bay), while the Nederrijn flows west, parallel to the Waal and carries approximately two ninths of the flow. However, at Wijk bij Duurstede, the Nederrijn changes its name and becomes the Lek. It flows farther west, to rejoin the Noord River into the Nieuwe Maas and to the North Sea.

The name ''Rijn'', from here on, is used only for smaller streams farther to the north, which together once formed the main river Rhine in Roman times. Though they retained the name, these streams no longer carry water from the Rhine, but are used for draining the surrounding land and polders. From Wijk bij Duurstede, the old north branch of the Rhine is called Kromme Rijn ("Bent Rhine") past Utrecht, first Leidse Rijn ("Rhine of Leiden") and then, Oude Rijn ("Old Rhine"). The latter flows west into a sluice at Katwijk, where its waters can be discharged into the North Sea. This branch once formed the line along which the Limes Germanicus were built. During periods of lower sea levels within the various ice ages, the Rhine took a left turn, creating the Channel River, the course of which now lies below the English Channel.

Larger cities

Basel, Strasbourg, Karlsruhe, Mannheim, Ludwigshafen, Wiesbaden, Mainz, Koblenz, Bonn, Cologne, Düsseldorf, Neuss, Duisburg, Arnhem (Nederrijn), Nijmegen (Waal), Utrecht (Kromme Rijn) and Rotterdam (Nieuwe Maas).

Smaller cities

Chur, Konstanz, Schaffhausen, Breisach, Speyer, Worms, Bingen am Rhein, Rüdesheim am Rhein, Neuwied, Andernach, Bad Honnef, Königswinter, Niederkassel, Wesseling, Dormagen, Zons, Monheim am Rhein, Wesel, Xanten, Emmerich am Rhein, Zutphen (IJssel), Deventer (IJssel), Zwolle (IJssel) and Kampen (IJssel).

Sections

The course of the Rhine can be divided into:

the headwaters, until their confluence near Tamins-Reichenau

the ''Alpine Rhine'', from Tamins-Reichenau to Lake Constance

Lake Constance itself

the ''High Rhine'', from Lake Constance to Basel

the ''Upper Rhine'', from Basel to Bingen am Rhein

the ''Middle Rhine'', from Bingen am Rhein to Bonn

the ''Lower Rhine'', from Bonn to the North Sea

the Rhine-Meuse-Scheldt delta.

Headwaters

The Rhine carries its name without distinctive accessories only from the confluence of the Vorderrhein and Hinterrhein near Tamins-Reichenau. Above this point is the extensive catchment of the headwaters of the Rhine. It belongs almost exclusively to the Swiss Canton of Grisons, ranging from Gotthard Massif in the west via one valley lying in Ticino and Italy in the south to the Flüela Pass in the east.

The sources of the Rhine

Traditionally, Lake Toma near the Oberalp Pass in the Gotthard region is seen as the source of the Vorderrhein and the Rhine as a whole. The Hinterrhein rises in the Rheinwald valley below Mount Rheinwaldhorn.

Vorderrhein

The Vorderrhein (English: ''Anterior Rhine'') arises from numerous source streams in the upper Surselva and flows in an easterly direction. One source is ''Lai da Tuma'' (2345 m) 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 ''Reno di 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.

In its lower course the Vorderrhein flows through a gorge named ''Ruinaulta'' through the Flims Rockslide. The whole stretch of the Vorderrhein to the Rhine confluence near Reichenau-Tamins is accompanied by a long-distance hiking trail called ''Senda Sursilvana''.

Hinterrhein

The Hinterrhein (English: ''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 (Rheinwaldhorn, Rheinquellhorn and Güferhorn).

The Avers Rhine joins from the South. One of its the headwaters, the ''Reno di Lei'' (stowed in the Lago di Lei), is partially located in Italy. Near Sils the Hinterrhein 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 Julia (also spelled ''Gelgia''), which comes down from the Julier Pass.

"Rhine" as a common river name

Numerous larger and smaller tributary rivers bear the name of the ''Rhine'' or equivalent in various Romansh idioms like ''Rein'' or ''Ragn''. Examples:

Vorderrhine area: Vorderrhein / ''Rein Anteriur'', ''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''

Hinterrhein basin: ''Hinterrhein'' / ''Rein Posteriur'', ''Reno di Lei'', ''Madrischer Rhein'', ''Avers Rhein'', ''Jufer Rhein''

Albula-Landwasser area: In Dischma near Davos, far east of the Rhine, there's a place called ''Am Rin'' ("Upon Rhine"). A tributary of the Dischma is called ''Riner Tälli''. Nearby, on the other side of the Sertig, is the ''Rinerhorn''.

Alpine Rhine

Near Tamins-Reichenau 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 m to 396 m. It flows through a wide glacial alpine valley known as the Rhine Valley. Near Sargans a natural dam, only a few metres high, prevents it from flowing into the open Seeztal valley and then trough Lake Walen and Lake Zurich into the river Aare. The Alpine Rhine begins in the centre of the Swiss canton of Grisons, and later forms the border between Switzerland to the West and Liechtenstein and later Austria to the East.

The mouth of the Rhine into Lake Constance forms an inland delta. The delta is delimited in the West by the Old Rhine and in the East by a modern canalized section. 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'' ("Donkey"). 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.

Lake Constance

Lake Constance consists of three bodies of water: the Obersee ("upper lake"), the 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 .

Obersee

The flow of cold, gray mountain water continues for some distance into the lake. The cold water flows near the surface and at first doesn't mixes 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 reapppears on the surface at the northern (German) shore of the lake, off the island of 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. 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 upstreams.

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

The Seerhein is only four km long. It connects the Obersee with the 30 cm lower Untersee. Distance markers along the Rhine measure the distance from the bridge in the old city centre of Constance.

For most of its length, the Seerhein forms the border between Germany and Switzerland. The exception is the old city centre of Constance, 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 metres. Previously, the two lakes formed a single lake, as the name still suggest.

Untersee

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 Radolfzeller Aach adds large amounts of water from the Danube system to the Untersee.

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

Lake Untersee is part of the 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.

High Rhine

The High Rhine begins in Stein am Rhein at the western end of the Untersee. Unlike the Alpine Rhine and Upper Rhine, it flows to the west. It falls from 395 m to 252 m.

Some stretches of the High Rhine between Stein am Rhein and Eglisau form the border between Switzerland on the South bank and Germany in the North. On other stretches, both sides are Swiss; in fact most of the Canton of Schaffhausen is on the North bank. Between Eglisau and Basel, the High Rhine consistenly forms the border.

The Rhine Falls are situated below Schaffhausen. It has an average water flow of 373 m³/s (mean summer discharge 700 m³/s) and is the second largest waterfall in Europe in terms of potential energy, after Dettifoss in Iceland. The High Rhine is characterized by numerous dams. On the few remaining natural sections, there are still several rapids.

Near Koblenz in the Aargau, the river Aar joins the Rhine. With an average discharge of 557 m³/s, the Aar is more voluminous than the Rhine, which has an average discharge of 439 m³/s. Nevertheless, the Alpine Rhine is considered the main branch, because it is longer.

Upper Rhine

In the centre of Basel, the first major city in the course of the stream, is located the "Rhine knee"; this is a major bend, where the overall direction of the Rhine changes from West to North. Here the High Rhine ends. Legally, the Central Bridge is the boundary between High and Upper Rhine. The river now flows North as Upper Rhine through the Upper Rhine Plain, which is about 300 km long and up to 40 km wide. The most important tributaries in this area are the Ill below of Strasbourg, the Neckar in Mannheim and the Main across from Mainz. In Mainz, the Rhine leaves the Upper Rhine Valley and flows through the Mainz Basin.

The southern half of the Upper Rhine forms the border between France (Alsace) and Germany (Baden-Württemberg). The northern part forms the border between the German states of Rhineland-Palatinate in the West on the one hand, and Baden-Württemberg and Hesse on the other hand, in the east and north. A curiosity of this border line is that the parts of the city of Mainz on the right bank of the Rhine were given to Hesse by the occupying forces in 1945.

The Upper Rhine was a significant cultural landscape in Central Europe already in antiquity and during the Middle Ages. Today, the Upper Rhine area hosts many important manufacturing and service industries, particularly in the centers Basel, Strasbourg and Mannheim-Ludwigshafen. Strasbourg is the seat of the European Parliament, and so one of the three European capitals is located on the Upper Rhine.

The Upper Rhine region was changed significantly by a Rhine straightening program in the 19th Century. The rate of flow was increased and the ground water level fell significantly. Dead branches dried up and the amount of forests on the flood plains decreased sharply. On the French side, the Grand Canal d'Alsace was dug, which carries a significant part of the river water, and all of the traffic. In some places, there are large compensation pools, for example the huge ''Bassin de compensation de Plobsheim'' in Alsace.

Island Rhine

The section of the Upper Rhine downstreams of Mainz is also known as the Island Rhine. Here, a number of river islands are located, locally known as "Rheinauen"

Middle Rhine

The Mainz Basin ends in Bingen am Rhein; the Rhine continues as "Middle Rhine" into the Rhine Gorge in the Rhenish Slate Mountains. In this sections the river falls from 77.4 m above sea level to 504 m. On the left, is located the mountain ranges of Hunsrück and Eifel, on the right Taunus and Westerwald. According to geologists, the characteristic narrow valley form was created by erosion by the river while the surrounding landscape was lifted (see water gap).

Major tributaries in this section are the Lahn and the Moselle. They join the Rhine near Koblenz, for the right and left respectively. Almost the entire length of the Middle Rhine River runs in the German state of Rhineland-Palatinate.

The dominant economic sectors in the Middle Rhine area are viniculture and tourism. The Rhine Gorge between Rüdesheim am Rhein and Koblenz is listed as a UNESCO World Heritage Site. Near Sankt Goarshausen, the Rhine flows around the famous rock Lorelei. With its outstanding architectural monuments, the slopes full of vines, settlements crowded on the narrow river banks and scores of castles lined up along the top of the steep slopes, the Middle Rhine Valley can be considered the epitome of the Rhine romanticism.

Lower Rhine

In Bonn, where the Sieg flows into the Rhine, the Rhine enters the North German Plain and turns into the Lower Rhine. The Lower Rhine falls from 50 m to 12 m. The main tributaries on this stretch are the Ruhr and the Lippe. Like the Upper Rhine, the Lower Rhine sed to meander until engineering created a solid river bed. Because the levees are some distance from the river, at high tide the Lower Rhine has room for widening than the Upper Rhine.

The Lower Rhine flows through North Rhine-Westphalia. Its banks are usually heavily populated and industrialized, in particular the agglomerations Cologne, Düsseldorf and Ruhr area. Here the Rhine flows trough the largest conurbation in Germany, the Rhine-Ruhr region. The most important city in this region is Duisburg with the largest river port in Europe (Duisport). The region downstream of Duisburg is more agricultural. In Wesel, 30 km downstream of Duisburg, is located the western end of the second east-west shipping route, the Wesel-Datteln Canal, which runs parallel to the Lippe. Between Emmerich and Cleves the Emmerich Rhine Bridge, the longest suspension bridge in Germany, crosses the 400 m wide river. Near Krefeld, the river crosses the Uerdingen line, the line with separates the areas where Low German and High German are spoken.

Delta

The Rhine-Meuse Delta, the most important natural region of the Netherlands begins near Millingen aan de Rijn, close to the Dutch-German border with the division of the Rhine into Waal and Nederrijn. Since the Rhine contriubtes most of the water, the shorter term ''Rhine Delta'' is commonly used. However, this name is also used for the river delta where the Rhine flows into Lake Constance, so it is clearer to call the larger one ''Rhine-Meuse delta'', or even ''Rhine–Meuse–Scheldt delta'', as the Scheldt ends in the same delta.

The shape of the Rhine delta is determined by two bifurcations: first, at Millingen aan de Rijn, the Rhine splits into Waal and Nederrijn, and second near Arnhem, the IJssel branches off from the Nederrijn. This creates three main flows, two of which change names rather often. The largest and southern main branch begins as Waal and continues as Boven Merwede ("Upper Merwede"), Beneden Merwede ("Lower Merwede"), Noord River ("North River"), Nieuwe Maas ("New Meuse"), Het Scheur ("the Rip") and Nieuwe Waterweg ("New Waterway"). The middle flow begins as Nederrijn, then changes into Lek, then joins the Noord, thereby forming Nieuwe Maas. The northern flow keeps the name IJssel until it flows into Lake IJsselmeer. Three more flows carry significant amounts of water: the Nieuwe Merwede ("New Merwede"), which branches off from the southern branch where it changes from Boven to Beneden Merwede; the Oude Maas ("Old Meuse"), which branches off from the southern branch where it changes from Beneden Merwede into Noord, and Dordtse Kil, which branches off from Oude Maas.

Before the St. Elizabeth's flood (1421), the Meuse flowed just south of today's line Merwede-Oude Maas to the North Sea and formed an archipelago-like estuary with Waal and Lek. This system of numerous bays, estuary-like extended rivers, many islands and constant changes of the coastline, is hard to imagine today. From 1421 to 1904, the Meuse and Waal merged further upstream at Gorinchem to form Merwede. For flood protection reasons, the Meuse was separated from the Waal through a lock and diverted into a new outlet called "Bergse Maas", then Amer and then flows into the former bay Hollands Diep.

The northwestern part of the estuary (around Hook of Holland), is still called ''Maasmond'' ("Meuse Mouth"), ignoring the fact that it now carries only water from the Rhine. This might explain the confusing naming of the various branches.

The hydrography of the current delta is characterized by the delta's main arms, disconnected arms (Hollandse IJssel, Linge, Vecht, etc.) and smaller rivers and streams. Many rivers have been closed ("dammed") and now serve as drainage channels for the numerous polders. The construction of Delta Works changed the Delta in the second half of the 20th Century fundamentally. Currently Rhine water runs into the sea, or into former marine bays now separated from the sea, in five places, namely at the mouths of the Nieuwe Merwede, Nieuwe Waterway (Nieuwe Maas), Dordtse Kil, Spui and IJssel.

The Rhine-Meuse Delta is a tidal delta, shaped not only by the sedimentation of the rivers, but also by tidal currents. This meant that high tide formed a serious risk because strong tidal currents could tear huge areas of land into the sea. Before the construction of the Delta Works, tidal influence was palpable up to Nijmegen, and even today, after the regulatory action of the Delta Works, the tide acts far inland. At the Waal, for example, the most landward tidal influence can be detected between Brakel and Zaltbommel.

Railway Crossings

Tributaries

Tributaries from source to mouth: Left

Thur River (Switzerland)

Töss River

Aar (Aare)

Birs

Birsig

Ill (France)

Moder River

Lauter (Rhine)

Nahe River

Moselle River

Nette (Rhine)

Ahr

Erft

Meuse River (joins part of the Rhine in the shared delta)

Right

Hinterrhein River

Ill (Austria)

Schussen

Wutach River

Alb

Wiese

Elz (Rhine)

Kinzig (Rhine)

Rench

Acher

Murg

Alb

Pfinz

Neckar

Main

Lahn

Wied River

Sieg

Wupper

Düssel

Ruhr

Emscher

Lippe River

Oude IJssel

Berkel

Former distributaries

''Order: panning North to South through the Western Netherlands'':

Vecht (Utrecht) (minor channel in Roman times, flowing into former Zuider Zee lagoon)

Kromme Rijn – Oude Rijn (Utrecht and South Holland) (main channel in Roman times, dammed in 12th century AD)

Hollandse IJssel (formed after Roman times, dammed in 13th century AD)

Linge (big channel in Roman times, dammed in 14th century AD)

De Biesbosch-area (initiated by AD 1421–1424 storm surges and river floods, by-passed since the digging of Nieuwe Merwede canal in AD 1904)

Canals

''Order: upstream to downstream'':

Rhine–Main–Danube Canal – southeastern Germany

Grand Canal d'Alsace – eastern France

Rhine-Herne Canal – northwest Germany, connection to the Dortmund-Ems Canal and the Mittellandkanal

Maas-Waal Canal – eastcentral Netherlands

Amsterdam-Rhine Canal – central Netherlands

Scheldt-Rhine Canal – southwest Netherlands

Canal of Drusus

Geologic history

Alpine orogeny

The Rhine flows from the Alps to the North Sea Basin; the geography and geology of its present day watershed has been developing, since the Alpine orogeny began.

In southern Europe, the stage was set in the Triassic Period of the Mesozoic Era, with the opening of the Tethys Ocean, between the Eurasian and African tectonic plates, between about 240 MBP and 220 MBP (million years before present). The present Mediterranean Sea descends from this somewhat larger Tethys sea. At about 180 MBP, in the Jurassic Period, the two plates reversed direction and began to compress the Tethys floor, causing it to be subducted under Eurasia and pushing up the edge of the latter plate in the Alpine Orogeny of the Oligocene and Miocene Periods. Several microplates were caught in the squeeze and rotated or were pushed laterally, generating the individual features of Mediterranean geography: Iberia pushed up the Pyrenees; Italy, the Alps, and Anatolia, moving west, the mountains of Greece and the islands. The compression and orogeny continue today, as shown by the ongoing raising of the mountains a small amount each year and the active volcanoes.

In northern Europe, the North Sea Basin had formed during the Triassic and Jurassic periods and continued to be a sediment receiving basin since. In between the zone of Alpine orogeny and North Sea Basin subsidence, remained highlands resulting from an earlier orogeny (Variscan), such as the Ardennes, Eifel and Vosges.

From the Eocene onwards, the ongoing Alpine orogeny caused a N–S rift system to develop in this zone. The main elements of this rift are the Upper Rhine Graben, in southwest Germany and eastern France and the Lower Rhine Embayment, in northwest Germany and the southeastern Netherlands. By the time of the Miocene, a river system had developed in the Upper Rhine Graben, that continued northward and is considered the first Rhine river. At that time, it did not yet carry discharge from the Alps; instead, the watersheds of the Rhone and Danube drained the northern flanks of the Alps.

Stream capture

The watershed of the Rhine reaches into the Alps today, but it did not start out that way. In the Miocene period, the watershed of the Rhine reached south, only to the Eifel and Westerwald hills, about north of the Alps. The Rhine then had the Sieg as a tributary, but not yet the Moselle River. The northern Alps were then drained by the Danube.

Through stream capture, the Rhine extended its watershed southward. By the Pliocene period, the Rhine had captured streams down to the Vosges Mountains, including the Mosel, the Main and the Neckar. The northern Alps were then drained by the Rhone. By the early Pleistocene period, the Rhine had captured most of its current Alpine watershed from the Rhône, including the Aar. Since that time, the Rhine has added the watershed above Lake Constance (Vorderrhein, Hinterrhein, Alpenrhein; captured from the Rhône), the upper reaches of the Main, beyond Schweinfurt and the Vosges Mountains, captured from the Meuse River, to its watershed.

Around 2.5 million years ago (ending 11,600 years ago) was the geological period of the Ice Ages. Since approximately 600,000 years ago, six major Ice Ages have occurred, in which sea level dropped and much of the continental margins became exposed. In the Early Pleistocene, the Rhine followed a course to the northwest, through the present North Sea. During the so-called Anglian glaciation (~450,000 yr BP, marine oxygen isotope stage 12), the northern part of the present North Sea was blocked by the ice and a large lake developed, that overflowed through the English Channel. This caused the Rhine's course to be diverted through the English Channel. Since then, during glacial times, the river mouth was located offshore of Brest, France and rivers, like the Thames and the Seine, became tributaries to the Rhine. During interglacials, when sea level rose to approximately the present level, the Rhine built deltas, in what is now the Netherlands.

The last glacial ran from ~74,000 (BP = Before Present), until the end of the Pleistocene (~11,600 BP). In northwest Europe, it saw two very cold phases, peaking around 70,000 BP and around 29,000–24,000 BP. The last phase slightly predates the global last ice age maximum (Last Glacial Maximum). During this time, the lower Rhine flowed roughly west through the Netherlands and extended to the southwest, through the English Channel and finally, to the Atlantic Ocean. The English Channel, the Irish Channel and most of the North Sea were dry land, mainly because sea level was approximately lower than today.

Most of the Rhine's current course was not under the ice during the last Ice Age; although, its source must still have been a glacier. A tundra, with Ice Age flora and fauna, stretched across middle Europe, from Asia to the Atlantic Ocean. Such was the case during the Last Glacial Maximum, ca. 22,000–14,000 yr BP, when ice-sheets covered Scandinavia, the Baltics, Scotland and the Alps, but left the space between as open tundra. The loess or wind-blown dust over that tundra, settled in and around the Rhine Valley, contributing to its current agricultural usefulness.

End of the last Ice Age

As northwest Europe slowly began to warm up from 22,000 years ago onward, frozen subsoil and expanded alpine glaciers began to thaw and fall-winter snow covers melted in spring. Much of the discharge was routed to the Rhine and its downstream extension. Rapid warming and changes of vegetation, to open forest, began about 13,000 BP. By 9000 BP, Europe was fully forested. With globally shrinking ice-cover, ocean water levels rose and the English Channel and North Sea re-inundated. Meltwater, adding to the ocean and land subsidence, drowned the former coasts of Europe transgressionally.

About 11000 yr ago, the Rhine estuary was in the Dover Strait. There remained some dry land in the southern North Sea, connecting mainland Europe to Britain. About 9000 yr ago, that last divide was overtopped / dissected. These events were well within the residence of man.

Since 7500 yr ago, a situation with tides and currents, very similar to present has existed. Rates of sea-level rise had dropped so far, that natural sedimentation by the Rhine and coastal processes together, could compensate the transgression by the sea; in the last 7000 years, the coast line was roughly at the same location. In the southern North Sea, due to ongoing tectonic subsidence, the sea-level is still rising, at the rate of about per century (1 metre or 39 inches in last 3000 years).

About 7000–5000 BP, a general warming encouraged migration up the Danube and down the Rhine, by peoples to the east, perhaps encouraged by the sudden massive expansion of the Black Sea, as the Mediterranean Sea burst into it through the Bosporus, about 7500 BP.

Holocene delta

At the begin of the Holocene (~11,700 years ago), the Rhine occupied its Late-Glacial valley. As a meandering river, it reworked its ice-age braidplain. As sea-level continued to rise in the Netherlands, the formation of the Holocene Rhine-Meuse delta began (~8,000 years ago). Coeval absolute sea-level rise and tectonic subsidence have strongly influenced delta evolution. Other factors of importance to the shape of the delta are the local tectonic activities of the Peel Boundary Fault, the substrate and geomorphology, as inherited from the Last Glacial and the coastal-marine dynamics, such as barrier and tidal inlet formations.

Since ~3000 yr BP (= years Before Present), human impact is seen in the delta. As a result of increasing land clearance (Bronze Age agriculture), in the upland areas (central Germany), the sediment load of the Rhine River has strongly increased and delta growth has sped up. This caused increased flooding and sedimentation, ending peat formation in the delta. The shifting of river channels to new locations, on the floodplain (termed avulsion), was the main process distributing sediment across the subrecent delta. Over the past 6000 years, approximately 80 avulsions have occurred. Direct human impact in the delta started with peat mining, for salt and fuel, from Roman times onward. This was followed by embankment, of the major distributaries and damming of minor distributaries, which took place in the 11–13th century AD. Thereafter, canals were dug, bends were short cut and groynes were built, to prevent the river's channels from migrating or silting up.

At present, the branches Waal and Nederrijn-Lek discharge to the North Sea, through the former Meuse estuary, near Rotterdam. The river IJssel branch flows to the north and enters the IJsselmeer, formerly the Zuider Zee brackish lagoon; however, since 1932, a freshwater lake. The discharge of the Rhine is divided among three branches: the River Waal (6/9 of total discharge), the River Nederrijn – Lek (2/9 of total discharge) and the River IJssel (1/9 of total discharge). This discharge distribution has been maintained since 1709, by river engineering works, including the digging of the Pannerdens canal and since the 20th century, with the help of weirs in the Nederrijn river.

Prehistory

Paleolithic

During the Middle Paleolithic (ca 100,000–30,000 BP), Western Europe, including the Rhine and Danube Valleys, was occupied by the Neanderthal, to which belonged the Mousterian culture of stone tools. Mousterian sites are not considered intrusive. It is believed that the Neanderthals may have evolved from the preceding Homo erectus in the vicinity of the glaciers, but the question has by no means been settled definitively.

Neanderthal sites are denser to the south, where open forest prevailed and the limestone terrain offered more caves as dwellings. The Rhine ran through an open tundra, where Neanderthals hunted big game, such as the rhinoceros and the woolly mammoth. Accordingly, open air Mousterian sites have been discovered in and around the Rhine valley.

Mesolithic

Before approximately 5600 BC, the Rhine Valley, along with most of Europe, was occupied by Cro-Magnon man, in the Mesolithic stage of cultural development; that is, they hunted and gathered, but owned a larger and more specialized tool kit than the Paleolithic people, knew more about the plants and animals, and even may have kept a few animals.

Iron Age

During the early Iron Age, both banks of the Rhine were inhabited by Celtic tribes. However, in the beginning of the Pre-Roman Iron Age (ca 600 BC), the Proto-Germanic tribes crossed the Weser River and the Aller, expanding the whole distance to the banks of the Rhine. This expansion is shown archaeologically in the form of the Jastorf culture. From ca 500 BC onwards, the lower Rhine, not the Weser or the Aller, would increasingly mark the border between the Celtic and Germanic tribes.

Historic and military relevance

The human history of the Rhine begins with the writers of the late Roman Republic and early Roman Empire. Nearly all the classical sources mention the Rhine and the name is always the same: Rhenus in Latin or Rheonis in Greek. The Romans viewed the Rhine as the outermost border of civilization and reason, beyond which were mythical creatures and wild Germanic tribesmen, not far themselves from being beasts of the wilderness they inhabited.

As it was a wilderness, the Romans were eager to explore it. This view is typified by ''Res Gestae Divi Augusti'', a long public inscription of Augustus, in which he boasts of his exploits; including, sending an expeditionary fleet north of the Rheinmouth, to Old Saxony and Jutland, which he claims no Roman had ever done.

Throughout the long history of Rome, the Rhine was considered the border between Gaul or the Celts and the Germanic peoples; although, it should be noted that the historical ethnonyms do not carry their modern ethno-linguistic definitions. Typical of this point of view is a quote from Maurus Servius Honoratus, ''Commentary on the Aeneid of Vergil'' (On Book 8 Line 727): :"''(Rhenus) fluvius Galliae, qui Germanos a Gallia dividit''" :"''(The Rhein is a) river of Gaul, which divides the Germanic people from Gaul.''"

The Rhine, in the earlier sources, was always a Gallic river.

As the Roman Empire grew, the Romans found it necessary to station troops along the Rhine. They kept two army groups there (exercitus), the inferior or "lower", and the superior or "upper", which is the first distinction between upper Germania and lower Germania. It originally probably only meant upstream and downstream ("Niederrhein" and "Oberrhein", respectively; see the map above).

The Romans kept eight legions in five bases along the Rhine. The actual number of legions present at any base or in all, depended on whether a state or threat of war existed. Between about AD 14 and 180, the assignment of legions was as follows: for the army of Germania Inferior, two legions at Vetera (Xanten), I Germanica and XX Valeria (Pannonian troops); two legions at oppidum Ubiorum ("town of the Ubii"), which was renamed to Colonia Agrippina, descending to Cologne, V Alaudae, a Celtic legion recruited from Gallia Narbonensis and XXI, possibly a Galatian legion from the other side of the empire.

For the army of Germania Superior: one legion, II Augusta, at Argentoratum (Strasbourg); and one, XIII Gemina, at Vindonissa (Windisch). Vespasian had commanded II Augusta, before his promotion to imperator. In addition, were a double legion, XIV and XVI, at Moguntiacum (Mainz).

The two originally military districts, of Germania Inferior and Germania Superior, came to influence the surrounding tribes, who later respected the distinction in their alliances and confederations. For example, the upper Germanic peoples combined into the Alemanni. For a time, the Rhine ceased to be a border, when the Franks crossed the river and occupied Roman-dominated Celtic Gaul, as far as Paris.

The first urban settlement, on the grounds of what is today the centre of Cologne, along the Rhine, was ''Oppidum Ubiorum'', which was founded in 38 BC, by the Ubii, a Germanic tribe. Cologne became acknowledged, as a city by the Romans in AD 50, by the name of ''Colonia Claudia Ara Agrippinensium''. Considerable Roman remains can be found in contemporary Cologne, especially near the wharf area, along the Rhine, where a notable discovery, of a 1900 year old Roman boat, was made on the Rhine banks, in late 2007.

Subsequently, language changes began to play a major political role. West Germanic dissimilated into Low Saxon; Low Franconian languages and High German languages, roughly along the old lines. Perhaps, it had been doing so all along. Charlemagne united all the Franks in the Holy Roman Empire, but he did not rule over a people of uniform language. After his death, the empire split, more or less along language lines, with the Low Franconian being spoken in the Netherlands and the Low Saxon and High German, in what became Germany. The Romanized Franks became the French. The Rhine once again became a political border.

The Rhine as a border has been and still is a mystical and political symbol. German authors and composers have written reams about it. During World War II, it was still considered the sacred border, of Germany and still was a defensive barrier.

Historical context

The Rhine is closely linked to many important historical events – particularly military ones – as well as myths. For example:

The Battle of the Teutoburg Forest, which finally established the Rhine as the northern frontier of the Roman Empire.

It was a historic object of frontier trouble, between France and Germany. Establishing "natural borders" on the Rhine was a long term goal of French foreign policy, since the Middle Ages; though, the language border was – and is – far more to the west. French leaders, such as Louis XIV and Napoleon Bonaparte, tried with varying degrees of success to annex lands west of the Rhine. The Confederation of the Rhine was established by Napoleon, as a French client republic, in 1806 and lasted until 1814, during which time it served as a significant source of resources and military manpower for the First French Empire. In 1840, the ''Rhine crisis'' evolved, because the French prime minister, Adolphe Thiers, started to talk about the Rhine border. In response, the poem and song, ''Die Wacht am Rhein'' (''The Watch on the Rhine''), was composed at that time, calling for the defense of the western bank of the Rhine against France. During the Franco-Prussian War, it rose to the de-facto status of a national anthem in Germany. The song remained popular in World War I and was used in the movie ''Casablanca''.

At the end of World War I, the Rhineland was subject to the Treaty of Versailles. This decreed that it would be occupied by the allies, until 1935 and after that, it would be a demilitarised zone, with the German army forbidden to enter. The Treaty of Versailles and this particular provision, in general, caused much resentment in Germany and is often cited as helping Adolf Hitler's rise to power. The allies left the Rheinland, in 1930 and the German army re-occupied it in 1936, which was enormously popular in Germany. Although the allies could probably have prevented the re-occupation, Britain and France were not inclined to do so, a feature of their policy of appeasement to Hitler.

In World War II, it was recognised that the Rhine would present a formidable natural obstacle to the invasion of Germany, by the western allies. The Rhine bridge at Arnhem, immortalized in the book, ''A Bridge Too Far'' and the film, was a central focus of the battle for Arnhem, during the failed Operation Market Garden of September 1944. The bridges at Nijmegen, over the Waal distributary of the Rhine, were also an objective of Operation Market Garden. In a separate operation, the Ludendorff Bridge, crossing the Rhine at Remagen, became famous, when U.S. forces were able to capture it intact – much to their own surprise – after the Germans failed to demolish it. This also became the subject of a film, ''The Bridge at Remagen''.

In November 1986, fire broke out in a chemical factory near Basel, Switzerland. Chemicals soon made their way into the river and caused pollution problems. About 30 tons of chemicals were discharged into the river. Locals were told to stay indoors, as foul smells were present in the area. The pollutants included pesticides, mercury, and other highly poisonous agricultural chemicals.

The ''Nibelungenlied'', an epic poem in Middle High German, tells the saga of Siegfried/Sigurd, who killed a dragon on the Drachenfels (Siebengebirge) ("dragons rock"), near Bonn at the Rhine and of the Burgundians and their court at Worms, at the Rhine and Kriemhild's golden treasure, which was thrown into the Rhine by Hagen.

''Das Rheingold'' – inspired by the ''Nibelungenlied'', the Rhine is one of the settings for the first opera of Richard Wagner's ''Der Ring des Nibelungen''. The action of the epic opens and ends underneath the Rhine, where three Rheinmaidens swim and protect a hoard of gold.

The Loreley/Lorelei is a rock on the eastern bank of the Rhine, that is associated with several legendary tales, poems and songs. The river spot has a reputation for being a challenge for inexperienced navigators.

Many historic castles are located along the Rhine.

''Seven Days to the River Rhine'' was a Warsaw Pact war plan for an invasion of Western Europe during the Cold War.

See also

KD Steamer

Witenwasserenstock (triple watershed: Rhone–Rhine–Po)

Piz Lunghin (triple watershed: Po–Rhine–Danube)

Notes

References

External links

Rhine online water guide and map

Bibliography on Water Resources and International Law Peace Palace Library

Etymology

The ''*rei–'' root, ''The American Heritage Dictionary of the English Language''

Geology

Britain's drowned landscapes

New dating of the European Ice Age

Regional Tectonics: from the Rhine Graben

Rhine–Meuse delta studies

Universität Basel – Upper Rhine Graben Evolution and Neotectonics

History

Rhine history and maps

Rhine–Meuse delta studies

Roman Rhine

Navigation

Rhein Navigation Commission

Castles

Castles on the Rhine river in Germany

Travel guide

Tomasee and three gorges in Switzerland of the headwaters of the rhine on official tourism board Grisons

Aerial Photos of the Upper Middle Rhine Valley World Heritage

Official Guide to the Middle Rhein (UNESCO World Heritage)

Article about the Middle Rhine Valley with nice photo gallery (German)

Wikimedia sister projects

Category:Austria–Switzerland border *(railway) Category:France–Germany border Category:Germany–Switzerland border Category:International rivers of Europe Category:Liechtenstein–Switzerland border Category:North Sea Category:Rhine–Meuse–Scheldt delta Category:Rift valleys Category:Rivers of Austria Category:Rivers of Baden-Württemberg Category:Rivers of France Category:Rivers of Germany Category:Rivers of the Netherlands Category:Rivers of Liechtenstein Category:Rivers of North Rhine-Westphalia Category:Rivers of Rhineland-Palatinate Category:Rivers of Switzerland

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