The International Commission for the Hydrology of the Rhine Basin (CHR) 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 theclimate crisis.[4][5]
The variants of the name of the Rhine (Latin Rhenus; French Rhin, Italian Reno, Romansh Rain or Rein, Dutch Rijn, Alemannic Ry, Ripuarian Rhing)[8] in modern languages are all derived from theGaulish nameRēnos, which was adapted inRoman-era geography (1st century BC) as LatinRhenus,[note 3] and as GreekῬῆνος (Rhēnos).
The modern German diphthongRhein (also used inRomansh)Rein, Rain is aCentral German development of theearly modern period, with theAlemannic nameRhi(n) keeping the older vocalism. In Alemannic, the deletion of the ending-n in pausa is a recent development; the formRhin is largely preserved inLucernese dialects.[11] hasRhing inRipuarian is diphthongized, as isRhei, Rhoi inPalatine. While Spanish has adopted the Germanic vocalismRin-, Italian, Occitan, and Portuguese have retained the LatinRen-.
The grammatical gender of theCeltic name (as well as of its Greek and Latin adaptation) 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 itsOld Icelandic adoption was inflected as feminine.[13]
The length of the Rhine is conventionally measured in "Rhine-kilometers" (Rheinkilometer), a scale introduced in 1939 that runs from the 0 km datum atOld Rhine Bridge in the city ofKonstanz, at the western end ofLake Constance, to theHook 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.[note 6] The "total length of the Rhine", to the inclusion of Lake Constance and theAlpine Rhine is more difficult to measure objectively; it was cited as 1,232 kilometers (766 miles) by the Dutch Rijkswaterstaat in 2010.[note 1]
^Average discharge for the years 1961–1990 as measured at Basel.[20] Discharges of 2,500 m3/s are regularly achieved during annual peaks, and discharges of over 4,000 m3/s have been recorded during exceptional flooding events.[21]
^At the confluence of the Aare and the Rhine, the Aare at 564 m3/s[22] carries more water on average than the Rhine at 442 m3/s,[23] so that hydrographically speaking the Rhine is a right tributary of the Aare.
^The total discharge of the Rhine is subject to significant fluctuations, and average values cited vary between sources; the total discharge given here consists of:Maasmond, 1450 m3/s;Haringvliet, 820 m3/s;Den Oever, 310 m3/s;Kornwerderzand, 220 m3/s;IJmuiden, 9 m3/s; and theScheldt–Rhine Canal, 10 m3/s.
Traditionally,Lake Toma near theOberalp Pass in the Gotthard region is seen as the source of the Anterior Rhine and the Rhine as a whole. The Posterior Rhine rises in theRheinwald below theRheinwaldhorn.
The confluence of the Anterior Rhine to the lower left and the Posterior Rhine in the background forms theAlpine Rhine (to the left) next toReichenau.
The source of the river is generally considered north ofLai da Tuma/Tomasee onRein Anteriur/Vorderrhein,[25] although its southern tributaryRein da Medel is actually longer before its confluence with the Anterior Rhine nearDisentis.
TheAnterior Rhine (Romansh:Rein Anteriur,German:Vorderrhein) springs fromLai da Tuma/Tomasee, near theOberalp Pass and passes the impressiveRuinaulta formed by the largest visible rock slide in the alps, theFlims Rockslide.
ThePosterior Rhine (Romansh:Rein Posteriur,German:Hinterrhein) starts from theParadies Glacier, near theRheinwaldhorn. One of its tributaries, theReno di Lei, drains theValle di Lei on politically Italian territory. After three main valleys separated by the two gorges,Roflaschlucht andViamala, it reachesReichenau inTamins.
Map of the Alpine Rhine
The Anterior Rhine arises from numerous source streams in the upperSurselva and flows in an easterly direction. One source isLai da Tuma (2,345 m (7,694 ft))[26] with theRein 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 theRein da Medel, theRein da Maighels, and theRein da Curnera. The Cadlimo Valley in thecanton of Ticino is drained by theReno di Medel, which crosses thegeomorphologic Alpine main ridge from the south.[note 7] 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 thePiz Russein of the Tödi massif of theGlarus Alps at 3,613 meters (11,854 ft) above sea level. It starts with the creekAua da Russein (lit.: "Water of the Russein").[27]
In its lower course, the Anterior Rhine flows through a gorge namedRuinaulta (Flims Rockslide). 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 calledSenda Sursilvana.[28]
TheAvers Rhine joins from the south. One of its headwaters, theReno di Lei (stowed in theLago di Lei), is partially located in Italy.
NearSils the Posterior Rhine is joined by theAlbula, from the east, from theAlbula Pass region. The Albula draws its water mainly from theLandwasser with theDischmabach as the largest source stream, but almost as much from theGelgia, which comes down from theJulier Pass.
Numerous larger and smaller tributary rivers bear the name of theRhine or equivalent in variousRomansh idioms, includingRein orRagn, including:
Posterior Rhine basin:Rein Posteriur/Hinterrhein,Reno di Lei,Madrischer Rhein,Avers Rhine,Jufer Rhein
Albula-Landwasser area: In theDischma valley, near Davos, far east of the Rhine, there's a place calledAm Rin ("Upon Rhine"). A tributary of the Dischma is calledRiner Tälli. Nearby, on the other side of theSertig, is theRinerhorn.
The Rhine betweenSargans in Switzerland (left) andBalzers inLiechtenstein (right) with theGonzen (1,829 m (6,001 ft), left), theGirrenspitz (2,099 m (6,886 ft)) in the back, and the Maziferchopf (855 m (2,805 ft)) to the right
Next toReichenau inTamins theAnterior Rhine and thePosterior Rhine join and form the Alpine Rhine. The river makes a distinctive turn to the north nearChur. 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 (German:Rheintal). NearSargan a natural dam, only a few meters high, prevents it from flowing into the openSztal valley and then throughLake Walen andLake Zurich into theAare. The Alpine Rhine begins in the westernmost part of the Swiss canton ofGraubünden, and later forms the border between Switzerland to the west and Liechtenstein and later Austria to the east.
Themouth of the Rhine into Lake Constance forms aninland delta. The delta is delimited in the west by theAlter Rhein and in the east by the modern canalized section of the Alpine Rhine (Fußacher Durchstich). Most of the delta is anature reserve andbird sanctuary. It includes the Austrian towns ofGaißau,Höchst andFußach. The natural Rhine originally branched into at least two arms and formed small islands by precipitating sediments. In the localAlemannic dialect, the singular is pronounced "Isel" and this is also the local pronunciation ofEsel ("Donkey"). Many local fields have an official name containing this element.
Aerial image of the mouth of the Rhine intoLake Constance
Aregulation of the Rhine was called for, with an upper canal nearDiepoldsau and a lower canal at Fußach, in order to counteract the constant flooding and strongsedimentation in the western Rhine Delta. TheDornbirner 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 LakeTuggenersee.
The cut-off Old Rhine at first formed aswamp landscape. Later an artificial ditch of about two km was dug. It was made navigable to the Swiss town ofRheineck.
Satellite image. In the center and on the right (i.e. to the east) the larger part of Lake Constance, called theObersee, is visible, and it includes, in the lower right, thedelta of theAlpine Rhine. The northwesterly "finger" (on the top left) isLake Überlingen, containing the island ofMainau. Below Lake Überlingen (also in the west) is the smallerUntersee, containingReichenau Island. The Obersee and Untersee are connected by the four kilometers longSeerhein. On the left theHigh Rhine can be seen.
The Rhine carries very large amounts of debris into the lake – over three million cubic meters (110,000,000 cu ft) annually.[29] In the mouth region, it is therefore necessary to permanently remove gravel by dredging. The largesediment loads are partly due to the extensiveland improvements upstream.
Three countries border the Obersee, namely Switzerland in the south, Austria in the southeast and the German states ofBavaria in the northeast andBaden-Württemberg in the north and northwest.
Distance markers along the Rhine indicate distances from this bridge inKonstanzThe 555 km marker downstream from theLorelei
TheSeerhein is only 4 kilometers (2.5 mi) long. It connects theObersee with the 30 cm (12 in) lowerUntersee. Distance markers along the Rhine measure the distance from thebridge 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 metres (33 ft). Previously, the two lakes formed a single lake, as the name still suggests.
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 andGnadensee) remain virtually unaffected by the flow. The river traverses the southern, which, in isolation, is sometimes calledRhinesee (lit.'Lake Rhine'). TheSchweizerische Schifffahrtsgesellschaft Untersee und Rhein (URh) offers regular boat trips on Untersee.
Besides theSeerhein, theRadolfzeller Aach is the main tributary ofUntersee. It adds large amounts of water from theDanube system to theUntersee via theDanube Sinkhole.
Reichenau Island was formed at the same time as the Seerhein, when the water level fell to its current level.
The High Rhine (Hochrhein) begins inStein am Rhein at the western end of the Untersee. Now flowing generally westwards, it passes over theRhine Falls (Rheinfall) belowSchaffhausen before being joined – nearKoblenz in thecanton of Aargau – by its major tributary, theAare. The Aare more than doubles the Rhine's water discharge, to an average of slightly more than 1,000 m3/s (35,000 cu ft/s),[note 8] and provides more than a fifth of the discharge at the Dutch border. The Aare also contains the waters from the 4,274 m (14,022 ft) summit ofFinsteraarhorn, the highest point of the Rhinebasin.
BetweenEglisau andBasel, the vast majority of its length, the High Rhine forms theborder between Germany and Switzerland. Only for brief distances at its extremities does the river run entirely within Switzerland; at the eastern end it separates the bulk of thecanton ofSchaffhausen and the Germanexclave ofBüsingen am Hochrhein on the northern bank from cantons ofZürich andThurgau, while at the western end it bisects the canton ofBasel-Stadt. Here, at theRhine knee, the river turns north and leaves Switzerland altogether.
The High Rhine is characterized by numerous dams. On the few remaining natural sections, there are still severalrapids. Over its entire course from Lake Constance to the Swiss border at Basel the river descends from 395 to 252 m (1,296 to 827 ft).
The Rhine inBasel is Switzerland's gateway to the sea.View of the Mainz Basin downstreams of Mainz, from Eltville and Erbach to Bingen
In the center of Basel, the first major city in the course of the stream, is theRhine knee, 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 theUpper Rhine Plain, which is about 300 km long and up to 40 km wide. The most important tributaries in this area are theIll below of Strasbourg, theNeckar in Mannheim and theMain 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 theborder between France (Alsace) and Germany (Baden-Württemberg). The northern part forms the border between the German states ofRhineland-Palatinate in the west on the one hand, andBaden-Württemberg andHesse on the other hand, in the east and north. A curiosity of this border line is that the parts of the city ofMainz 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 inantiquity and during theMiddle 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 theEuropean 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 were removed by construction workers and the area around the river was made more habitable for humans onflood plains as the rate of flooding decreased sharply. On the French side, theGrand 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 hugeBassin de compensation dePlobsheim in Alsace.
The Upper Rhine has undergone significant human change since the 19th century. While it was slightly modified during the Roman occupation, it was not until the emergence of engineers such asJohann Gottfried Tulla that significant modernization efforts changed the shape of the river. Earlier work underFrederick the Great surrounded efforts to ease shipping and construct dams to servecoal transportation.[33] Tulla is considered to have domesticated the Upper Rhine, a domestication that served goals such as reducing stagnantbogs that fostered waterborne diseases, making regions more habitable for human settlement, and reduce high frequency of floods. Not long before Tulla went to work on widening and straightening the river, heavy floods caused significant loss of life.[34] Four diplomatic treaties were signed among German state governments and French regions dealing with the changes proposed along the Rhine, one was "the Treaty for the Rectification of the Rhine flow from Neuberg to Dettenheim"(1817), which surrounded states such asBourbon France and theBavarian Palatinate. Loops,oxbows, branches and islands were removed along the Upper Rhine so that there would be uniformity to the river.[35] The engineering of the Rhine was not without protest, farmers and fishermen had grave concerns about valuable fishing areas and farmland being lost. While some areas lost ground, other areas saw swamps and bogs be drained and turned into arable land.[36] Johann Tulla had the goal of shortening and straightening the Upper Rhine. Early engineering projects the Upper Rhine also had issues, with Tulla's project at one part of the river creating rapids, after the Rhine cut down from erosion to sheer rock.[36] Engineering along the Rhine eased flooding and made transportation along the river less cumbersome. These state projects were part of the advanced and technical progress going on in the country alongside the industrial revolution. For the German state, making the river more predictable was to ensure development projects could easily commence.[37]
The section of the Upper Rhine downstream fromMainz is also known as the "Island Rhine". Here a number ofriver islands occur, locally known as "Rheinauen".
The Rhine is the longest river in Germany. It is here that the Rhine encounters some more of its main tributaries, such as theNeckar, theMain and, later, theMoselle, which contributes an average discharge of more than 300 m3/s (11,000 cu ft/s). Northeastern France drains to the Rhine via the Moselle; smaller rivers drain theVosges andJura Mountains uplands. Most ofLuxembourg and a very small part ofBelgium also drain to the Rhine via the Moselle. As it approaches the Dutch border, the Rhine has an annual mean discharge of 2,290 m3/s (81,000 cu ft/s) and an average width of 400 m (1,300 ft).
BetweenBingen am Rhein andBonn, theMiddle Rhine flows through theRhine Gorge, a formation which was created byerosion. The rate of erosion equaled theuplift 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 aUNESCO World Heritage Site (2002) and known as "the Romantic Rhine", with more than 40 castles and fortresses from theMiddle Ages and many quaint and lovely country villages.
The Mainz Basin ends inBingen am Rhein; the Rhine continues as "Middle Rhine" into theRhine Gorge in theRhenish Slate Mountains. In this sections the river falls from 77.4 m above sea level to 50.4 m. On the left, is located the mountain ranges ofHunsrück andEifel, on the rightTaunus andWesterwald. According to geologists, the characteristic narrow valley form was created byerosion by the river while the surrounding landscape was lifted (seewater gap).
Major tributaries in this section are theLahn and theMoselle. They join the Rhine nearKoblenz, for the right and left respectively. Almost the entire length of the Middle Rhine runs in the German state of Rhineland-Palatinate.
The dominant economic sectors in the Middle Rhine area areviniculture and tourism. TheRhine Gorge betweenRüdesheim am Rhein andKoblenz is listed as a UNESCOWorld Heritage Site. NearSankt Goarshausen, the Rhine flows around the famous rockLorelei. 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.
InBonn, where theSieg flows into the Rhine, the Rhine enters theNorth 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 theRuhr and theLippe. Like the Upper Rhine, the Lower Rhine used tomeander until engineering created a solid river bed. Because the levees are some distance from the river, at high tide the Lower Rhine has more room for widening than the Upper Rhine.
The Lower Rhine flows throughNorth Rhine-Westphalia. Its banks are usually heavily populated and industrialized, in particular theagglomerationsCologne, Düsseldorf andRuhr area. Here the Rhine flows through the largest conurbation in Germany, theRhine-Ruhr region. One of the most important cities in this region isDuisburg with the largestriver 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. BetweenEmmerich andCleves theEmmerich Rhine Bridge, the longest suspension bridge in Germany, crosses the 400-meter-wide (1,300 ft) river. NearKrefeld, the river crosses theUerdingen line, the line which separates the areas whereLow German andHigh German are spoken. The Rhine River is crossed by severalferries, including the one betweenBad Honnef andRolandseck, where theLohfelderfähre district is situated.
Until the early 1980s, industry was a major source of water pollution. Although many plants and factories can be found along the Rhine up intoSwitzerland, it is along theLower Rhine that the bulk of them are concentrated, as the river passes the major cities ofCologne,Düsseldorf andDuisburg. Duisburg is the home of Europe's largest inland port and functions as a hub to the sea ports ofRotterdam,Antwerp andAmsterdam. TheRuhr, 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 thereforestation ofSlag andbrownfields. The Ruhr currently provides the region with drinking water. It contributes 70 m3/s (2,500 cu ft/s) to the Rhine. Other rivers in theRuhr Area include theEmscher.
The central and northern parts of the Rhine-Meuse delta Changing theMeuse estuary in 1904: light blue old course, dark blue today's courseMap showing how the waters of the Rhine and Meuse rivers split into various branches of their combined deltaTheNederrijn atArnhem
The Dutch name for Rhine is "Rijn". The Rhine turns west and enters theNetherlands, where, together with the riversMeuse andScheldt, it forms the extensiveRhine-Meuse-Scheldt delta, with 25,347 km2 (9,787 sq mi) the largestriver delta in Europe.[38] Crossing the border into the Netherlands atSpijk, close toNijmegen andArnhem, the Rhine is at its widest, although the river then splits into three maindistributaries: theWaal,Nederrijn ("Nether Rhine") andIJssel.
The other third of the water flows through thePannerdens Kanaal and redistributes in the IJssel and Nederrijn. The IJssel branch carries one ninth of the water flow of theRhine north into theIJsselmeer (a former bay), while the Nederrijn carries approximately two-ninths of the flow west along a route parallel to the Waal. However, atWijk bij Duurstede, the Nederrijn changes its name and becomes theLek. It flows farther west, to rejoin theNoord into theNieuwe Maas and to the North Sea.
The nameRijn, from here on, is used only for smaller streams farther to the north, which together formed the main river Rhine inRoman times. Though they retained the name, these streams no longer carry water from the Rhine, but are used for draining the surrounding land andpolders. From Wijk bij Duurstede, the old north branch of the Rhine is calledKromme Rijn ("Bent Rhine") pastUtrecht, firstLeidse Rijn ("Rhine ofLeiden") and then,Oude Rijn ("Old Rhine"). The latter flows west into asluice atKatwijk, where its waters can be discharged into theNorth Sea. This branch once formed the line along which theLimes Germanicus were built. During periods of lower sea levels within the various ice ages, the Rhine took a left turn, creating theChannel River, the course of which now lies below the English Channel.
The Rhine-Meuse Delta, the most importantnatural region of theNetherlands begins nearMillingen aan de Rijn, close to the Dutch-German border with the division of the Rhine intoWaal andNederrijn. The region between the Dutch-German border and Rotterdam, where the Waal, Lek, and Meuse run more or less parallel, is colloquially known as the "Great Rivers". Since the Rhine contributes most of the water, the shorter termRhine Delta is commonly used. However, this name is also used for theriver delta where the Rhine flows intoLake Constance, so it is clearer to call the larger oneRhine-Meuse delta, or evenRhine–Meuse–Scheldt delta, as the Scheldt ends in the same delta.
The shape of the Rhine delta is determined by twobifurcations: first, atMillingen aan de Rijn, the Rhine splits intoWaal andPannerdens Kanaal, which changes its name toNederrijn atAngeren, and second nearArnhem, theIJssel 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 asBoven Merwede ("Upper Merwede"),Beneden Merwede ("Lower Merwede"),Noord ("the North"),Nieuwe Maas ("New Meuse"),Het Scheur ("the Rip") andNieuwe Waterweg ("New Waterway"). The middle flow begins asNederrijn, then changes intoLek, then joins the Noord, thereby forming Nieuwe Maas. The northern flow keeps the name IJssel until it flows into LakeIJsselmeer. Three more flows carry significant amounts of water: theNieuwe Merwede ("New Merwede"), which branches off from the southern branch where it changes from Boven to Beneden Merwede; theOude Maas ("Old Meuse"), which branches off from the southern branch where it changes from Beneden Merwede into Noord, andDordtse Kil, which branches off from Oude Maas.
Before theSt. Elizabeth's flood (1421), theMeuse flowed just south of today's line Merwede-Oude Maas to the North Sea and formed anarchipelago-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 atGorinchem to formMerwede. For flood protection reasons, the Meuse was separated from the Waal through a lock and diverted into a new outlet called "Bergse Maas", thenAmer and then flows into the former bay Hollands Diep.
The northwestern part of the estuary (aroundHook of Holland), is still calledMaasmond ("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 numerouspolders. The construction ofDelta 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 thesedimentation 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, thetide acts far inland. At the Waal, the most landward tidal influence can be detected betweenBrakel andZaltbommel.
The Rhine flows from theAlps to theNorth Sea Basin. The geography and geology of its present-day watershed has been developing since theAlpine orogeny began.
In southern Europe, the stage was set in theTriassic Period of theMesozoic Era, with the opening of theTethys Ocean, between the Eurasian and Africantectonic plates, between about 240 MBP and 220 MBP (million years before present). The presentMediterranean Sea descends from this somewhat larger Tethys sea. At about 180 MBP, in theJurassic 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 theOligocene andMiocene Periods. Several microplates were caught in the squeeze and rotated or were pushed laterally, generating the individual features of Mediterranean geography: Iberia pushed up thePyrenees;Italy, the Alps, andAnatolia, moving west, the mountains ofGreece 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, highlands resulting from an earlier orogeny (Variscan) remained, such as theArdennes,Eifel andVosges.
From theEocene onward, the ongoing Alpine orogeny caused a north–south rift system to develop in this zone. The main elements of this rift are theUpper Rhine Graben, in southwest Germany and eastern France and the Lower Rhine Embayment, in northwest Germany and the southeasternNetherlands. By the time of the Miocene, a river system had developed in theUpper 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 theRhone andDanube drained the northern flanks of the Alps.
The watershed of the Rhine reaches into theAlps today, but it did not start out that way.[39] In theMiocene period, the watershed of the Rhine reached south, only to theEifel andWesterwald hills, about 450 km (280 mi) north of the Alps. The Rhine then had theSieg as a tributary, but not yet theMoselle. The northern Alps were then drained by theDanube.
Throughstream capture, the Rhine extended its watershed southward. By thePliocene period, the Rhine had captured streams down to theVosges Mountains, including theMain and theNeckar. The northern Alps were then drained by theRhone. By the earlyPleistocene period, the Rhine had captured most of its current Alpine watershed from the Rhône, including theAare. Since that time, the Rhine has added the watershed aboveLake Constance (Vorderrhein,Hinterrhein, Alpenrhein; captured from the Rhône), the upper reaches of the Main, beyondSchweinfurt and the Moselle in the Vosges Mountains, captured during the Saale Ice-age from theMeuse, to its watershed.
Around 2.5 million years ago (ending 11,600 years ago) the Ice Ages began. Since approximately 600,000 years ago, six major glacial periods have occurred, in which sea level dropped as much as 120 m (390 ft) and much of the continental margins were exposed. In theEarly Pleistocene, the Rhine followed a course to the northwest, through the present North Sea. During the so-calledAnglian glaciation (~450,000 yr BP, marine oxygen isotope stage 12), the northern part of the presentNorth 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 ofBrest, France and rivers, like theRiver Thames and theSeine, 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 most recentglacial period ran from ~74,000 (BP = Before Present), until the end of thePleistocene (~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 theNorth Sea were dry land, mainly because sea level was approximately 120 m (390 ft) 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. Atundra, with Ice Age flora and fauna, stretched across middle Europe, from Asia to the Atlantic Ocean. Such was the case during theLast 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.Loess (wind-blown topsoil dust) arose from the south and North Sea plain settling on the slopes of the Alps, Urals and the Rhine Valley, rendering the valleys facing the prevailing winds especially fertile.
As northwest Europe slowly began to warm from 22,000 years ago onward, frozensubsoil and expandedalpine 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.[40] 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 landsubsidence, drowned the former coasts of Europetransgressionally.
About 11000 years ago, the Rhine estuary was in the Strait of Dover. There remained some dry land in the southernNorth Sea, known asDoggerland, connecting mainland Europe to Britain. About 9000 years ago, that last divide was overtopped / dissected. Humans were already resident in the area when these events happened.
Since 7500 years ago the situation of tides, currents and land-forms has resembled the present. Rates ofsea level rise dropped such that natural sedimentation by the Rhine and coastal processes widely compensate for transgression by the sea. In the southernNorth Sea, due to ongoingtectonic subsidence, the coastline and sea bed are sinking at the rate of about 1–3 cm (0.39–1.18 in) per century (1 meter or 39 inches in last 3000 years).
About 7000–5000 BP, a general warming encouraged migration of all former ice-locked areas, including up theDanube and down the Rhine by peoples to the east. Asudden massive expansion of the Black Sea as theMediterranean Sea burst into it through theBosporus may have occurred about 7500 BP.
At the beginning of theHolocene (~11,700 years ago), the Rhine occupied its Late-Glacial valley. As ameandering river, it reworked its ice-age floodplain. As sea-level rise continued in the Netherlands, the formation of the Holocene Rhine-Meuse delta began (~8,000 years ago). Coeval absolute sea-level rise andtectonic subsidence have strongly influenced delta evolution. Other factors of importance to the shape of the delta are the local tectonic activities of thePeel Boundary Fault, the substrate andgeomorphology, as inherited from the Last Glacial period and the coastal-marine dynamics, such as barrier and tidal inlet formations.[41]
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 has strongly increased[42] and delta growth has sped up.[43] This has caused increased flooding and sedimentation, ending peat formation in the delta. In the geologically recent past the main process distributing sediment across the delta has been the shifting of river channels to new locations on the floodplain (termed avulsion). Over the past 6000 years, approximately 80 avulsions have occurred.[39] Direct human impact in the delta began with the mining ofpeat for salt and fuel fromRoman 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 straightened andgroynes 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 Meuseestuary, near Rotterdam. The river IJssel branch flows to the north and enters theIJsselmeer (formerly theZuider Zee), initially a brackish lagoon but a freshwater lake since 1932. The discharge of the Rhine is divided into three branches: the Waal (6/9 of total discharge), the Nederrijn – Lek (2/9 of total discharge) and the IJssel (1/9 of total discharge). This discharge distribution has been maintained since 1709 by river engineering works including the digging of thePannerdens Kanaal and the installation, in the 20th century, of a series of weirs on theNederrijn.
The Rhine was not known toHerodotus and first enters the historical period in the 1st century BC inRoman-era geography.[44] At that time, it formed the boundary betweenGaul andGermania.It is estimated that Germanic tribes have been inhabiting the area since 2000 BCE.[45]
The Upper Rhine had been part of the areal of the lateHallstatt culture since the 6th century BC[46], and by the 1st century BC, the areal of theLa Tène culture covered almost its entire length, forming a contact zone with theJastorf culture, i.e. the locus of earlyCeltic-Germanic cultural contact.[47]
In Roman geography, the Rhine formed the boundary betweenGallia andGermania by definition; e.g.Maurus Servius Honoratus,Commentary on the Aeneid of Vergil (8.727)(Rhenus) fluvius Galliae, qui Germanos a Gallia dividit "(The Rhine is a) river of Gaul, which divides the Germanic people from Gaul."[48]
In Roman geography, the Rhine andHercynia Silva were considered the boundary of the civilized world; as it was a wilderness, the Romans were eager to explore it. This view is typified byRes Gestae Divi Augusti, a long public inscription ofAugustus, in which he boasts of his exploits; including, sending an expeditionary fleet north of the Rheinmouth, toOld Saxony andJutland, which he claimed no Roman had ever done before.[49]
Augustus ordered his stepson Roman generalDrusus to establish 50military camps along the Rhine, starting theGermanic Wars in 12 BC.[50] At this time, the plain of theLower Rhine was the territory of theUbii. The first urban settlement, on the grounds of what is today Downtown Cologne, along the Rhine, wasOppidum Ubiorum, which was founded in 38 BC by the Ubii. Cologne became acknowledged, as a city by the Romans in AD 50, by the name ofColonia Claudia Ara Agrippinensium.[51]
CastellumNigrum Pullum,Zwammerdam, Netherlands, artist impression Stevie Xinas
From the death of Augustus in AD 14 until after AD 70, Rome accepted as herGermanic frontier the water-boundary of the Rhine and upperDanube. Beyond these rivers she held only the fertile plain ofFrankfurt, opposite the Roman border fortress of Moguntiacum (Mainz), the southernmost slopes of theBlack Forest and a few scattered bridge-heads. The northern section of this frontier, where the Rhine is deep and broad, remained the Roman boundary until the empire fell. The southern part was different. The upper Rhine and upper Danube are easily crossed. The frontier which they form is inconveniently long, enclosing an acute-angled wedge of foreign territory between the modernBaden andWürttemberg. The Germanic populations of these lands seem in Roman times to have been scanty, and Roman subjects from the modernAlsace-Lorraine had drifted across the river eastwards.
The Romans kept eight legions in five bases along the Rhine. The number was reduced to four as more units were moved to the Danube. 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:
The two original military districts ofGermania Inferior andGermania 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 theAlemanni. For a time, the Rhine ceased to be a border, when theFranks crossed the river and occupied Roman-dominated CelticGaul, as far as Paris.
Since thePeace of Westphalia, the Upper Rhine formed a contentious border between France and Germany. Establishing "natural borders" on the Rhine was a long-term goal of French foreign policy, since theMiddle Ages, though thelanguage border was – and is – far more to the west. French leaders, such asLouis XIV andNapoleon Bonaparte, tried with varying degrees of success to annex lands west of the Rhine. TheConfederation of the Rhine was established by Napoleon, as a Frenchclient state, in 1806 and lasted until 1814, during which time it served as a significant source of resources and military manpower for theFirst French Empire. In 1840, theRhine crisis, prompted by French prime ministerAdolphe Thiers's desire to reinstate the Rhine as a natural border, led to a diplomatic crisis and a wave of nationalism in Germany.
Allied soldiers of theRoyal Newfoundland Regiment crossing the Rhine into Germany after the end of WWI, December 1918
The Rhine became an important symbol inGerman nationalism during the formation of the German state in the 19th century (seeRhine romanticism).
Das Rheingold – inspired by theNibelungenlied, the Rhine is one of the settings for the first opera ofRichard Wagner'sDer Ring des Nibelungen. The action of the epic opens and ends underneath the Rhine, where three Rheinmaidens swim and protect a hoard of gold.
TheLoreley/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.
At the end ofWorld War I, theRhineland was subject to theTreaty of Versailles. This decreed that it would be occupied by the allies, until 1935 and after that, it would be a demilitarized zone, with the German army forbidden to enter. The Treaty of Versailles and this particular provision, in general, caused much resentment in Germany. The Allies' troops left the Rhineland in 1930 and, following the rise to power ofAdolf Hitler, the German army re-occupied it in 1936, which proved an enormously popular action in Germany. Although the Allies could probably have prevented the reoccupation, Britain and France were not inclined to do so, a feature of their policy ofappeasement to Hitler.
Until 1932, the generally accepted length of the Rhine was 1,230 kilometers (760 mi). In 1932 the German encyclopedia Knaurs Lexikon stated the length as 1,320 kilometers (820 mi), presumably a typographical 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 at 1,232 kilometers (766 miles).[note 1]
During its course from the Alps to the North Sea, the Rhine passes through four countries and constitutes six different country borders. On the various parts:
the Anterior Rhine lies entirely within Switzerland, while at least one tributary to Posterior Rhine,Reno di Lei originates in Italy, but is not considered a part of the Rhine proper.
the Alpine Rhine flows within Switzerland tillSargans, from which it becomes the border between Switzerland (to the west) and Liechtenstein (to the east) untilOberriet, and the river never flows within Liechtenstein. It then becomes the border between Switzerland (to the west) and Austria (to the east) untilDiepoldsau where the modern and straight course enters Switzerland, while the original courseAlter Rhein makes a bend to the east and continues as the Swiss-Austrian border until the confluence atWidnau. From here the river continues as the border untilLustenau, where the modern and straight course enters Austria (the only part of the river that flows within Austria), while the original course makes a bend to the west and continues as the border, until both courses enterLake Constance.
the first half ofSeerhein, between the upper and lower body of Lake Constance, flows within Germany (and the city ofKonstanz), while the second is the German (to the north) – Swiss (to the south) frontier.
the first parts of the High Rhine, from Lake Constance toAltholz, the river alternates flowing within Switzerland and being the German-Swiss frontier (three times each). From Altholz the river is the German-Swiss border untilBasel, where it enters Switzerland for the last time.
the Upper Rhine is the border between France (to the west) and Switzerland (to the east) for a short distance, from Basel toHunningue. Here it becomes the Franco (to the west) – German (to the east) frontier untilAu am Rhein. Hence, the main course of the Rhine never flows within France, although some river canals do. From Au am Rhein the river flows within Germany.
the Middle Rhine flows entirely within Germany.
the Lower Rhine flows within Germany untilEmmerich am Rhein, where it becomes the border between The Netherlands (to the north) and Germany (to the south). AtMillingen aan de Rijn the river enters the Netherlands.
^abcdThe Rhine only has an official length scale (Rheinkilometer) downstream ofKonstanz. Its full length is subject to the definition of the Alpine Rhine. In 2010, there were media reports to the effect that the length of the Rhine had been consistently over-stated in 20th-century encyclopedias, and upon request by journalists, the DutchRijkswaterstaat gave a length of 1,232 kilometers (766 mi).[6][7]
^The Rhine was not known in the Hellenistic period. It is mentioned byCicero,In Pisonem 33.81.Strabo (1.4.3) mentions the countries "at the mouth of the Rhine"αἱ τοῦ Ῥήνου ἐκβολαί; "states that the countries "beyond the Rhine and as far asScythia"καὶ τὰ πέραν τοῦ Ῥήνου τὰ μέχρι Σκυθῶ should be considered unknown, asPytheas' account of remote nations cannot be trusted.
^Krahe (1964) claims the hydronym as "Old European", i.e. belonging to the oldest Indo-European layer of names predating the 6th century BC (Hallstatt D) Celtic expansion.[12][page needed]
^In Albanian/Illyrianrrhedh also means to "move, flow, run".Pokorny's (1959) "3.*er- : or- : r- 'to move, set in motion'" (pp. 326–32),laryngealist*h₁reiH-, with an-n- suffix; Celtic reflexes:Old Irishrenn "rapid",rían "sea", Middle Irishrian "river, way".The root gives the Germanic verb*rinnan (←*ri-nw-an) whence Englishrun (from a causative*rannjanan, Old Englisheornan); Gothicrinnan "run, flow", Old Englishrinnan, Old Norserinna "to run",rinno "brook"; cf. Sanskritrinati "causes to flow"; Root cognates without the-n- suffix include Middle Low Germanride "brook", Old Englishriþ "stream", Dutchril "running stream", Latinrivus "stream", Old Church Slavonicreka "river".; see also"Rhine".Online Etymology Dictionary. Douglas Harper. November 2001. Retrieved10 February 2009.
^most notably the straightening of the Upper Rhine planned byJohann Gottfried Tulla, completed during 1817–1876.
^The geomorphological ridge line does not necessarily coincide with thewatershed, since it refers to the average altitude in a surrounding circle
^The fact that the Aare contributes the larger portion of the combined volume – 51.8%, based on 1961–1990 averages[30] – means that in hydrographical terms the Rhine could be considered a tributary of the Aare, but the greater length of the Alpine Rhine means that it retains the designation as main branch.
^Gerber, A. (6 July 2022)."Klimaforscher Latif: Rhein könnte bei Dürre austrocknen" [Climate researcher Latif: The Rhine could dry out in the event of a drought].EUWID Wasser und Abwasser (in German). Gernsbach: EUWID Europäischer Wirtschaftsdienst. Retrieved9 January 2023.
^"Rhine River 90 km shorter than everyone thinks".The Local. 27 March 2010.Archived from the original on 19 August 2022."We checked it out and came to 1,232 kilometers," said Ankie Pannekoek, spokeswoman for the Dutch government hydrology office.
^ab"Maps of Switzerland – Swiss Confederation – GEWISS" (online map).Vorderrhein. Gewässernetz 1:2 Mio. National Map 1:200 000 (in German). Cartography by Swiss Federal Office of Topography swisstopo. Berne, Switzerland: Federal Office for the Environment FOEN. 2014. Retrieved4 January 2016 – via map.geo.admin.ch.
^ab"Maps of Switzerland – Swiss Confederation – GEWISS" (online map).Alpenrhein. Gewässernetz 1:2 Mio. National Map 1:2 Mio (in German). Cartography by Swiss Federal Office of Topography swisstopo. Berne, Switzerland: Federal Office for the Environment FOEN. 2014. Retrieved4 January 2016 – via map.geo.admin.ch.
^ab"Maps of Switzerland – Swiss Confederation – GEWISS" (online map).Lake Constance. Gewässernetz 1:200 000, Flussordnung. National Map 1:2 Mio (in German). Cartography by Swiss Federal Office of Topography swisstopo. Berne, Switzerland: Federal Office for the Environment FOEN. 2014. Retrieved5 January 2016 – via map.geo.admin.ch.
^ab"Maps of Switzerland – Swiss Confederation – GEWISS" (online map).High Rhine. Gewässernetz 1:2 Mio. National Map 1:2 Mio (in German). Cartography by Swiss Federal Office of Topography swisstopo. Berne, Switzerland: Federal Office for the Environment FOEN. 2014. Retrieved5 January 2016 – via map.geo.admin.ch.
^Bergmeister, U.; Kalt, L."Geschiebeführung" [Conveyance of bedload] (in German). Lustenau: Internationale Rheinregulierung. Archived fromthe original on 22 March 2012.
Berendsen, H. J. A.; Stouthamer, E. (2001).Palaeogeographic Development of the Rhine-Meuse Delta, the Netherlands. Assen: Koninklijke Van Gorcum.ISBN978-90-232-3695-5.OCLC48632545.
Frijters, I. D.; Leentvaar, J. (2003).Rhine Case Study(PDF). Technical Documents in Hydrology, PCCP series. Vol. 17. Paris: UNESCO International Hydrological Programme.OCLC55974122. SC/2003/WS/54.
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