At 1,320 kilometres (820 miles) and an average discharge of more than 2,000 cubic meters per second, the Rhine (Dutch Rijn, French Rhin, German Rhein, Italian: Reno, Romansch: Rein, ) is one of the longest and most important rivers in Europe. The name of the Rhine comes from the Celtic Renos, literally "that which flows", from the Proto-Indo-European root *rei- ("to flow, run"), which also gave the verb "to run" in English.
The Rhine and the Danube formed most of the northern frontier of the Roman Empire, and since those days the Rhine has been a vital navigable waterway, carrying trade and goods deep inland. It has also served as a defensive feature, and 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 controlling that portion of the river.
At over 1000 kilometres in length, the Rhine is the longest river primarily within 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 over 300 cubic meters per second.
Between Bingen and Bonn, the Middle Rhine flows through the Rhine Gorge, a formation created by erosion, which happened at about the same rate as an uplift in the region, leaving the river at about its original level, and the surrounding lands raised. This gorge is quite deep, and is the stretch of the river 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 (see links) and many lovely wine-villages.
Though many industries 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, Dusseldorf, and Duisburg. The Ruhr river, which joins the Rhine at Duisburg, is surprisingly clean, given the amount of industry on its banks, and is used for drinking water. It adds another 70 cubic meters per second to the Rhine. However other rivers from the Ruhr area, above all the Emscher, still cause a considerable degree of pollution. Approaching the Dutch border, the Rhine now has an average discharge of 2,290 cubic metres per second and an average width of more than 1,000 feet.
From here the situation becomes more complicated, as the name "Rhine" no longer coincides with the main flow of water. Most of the Rhine water (two thirds) flows further west through the Waal and then via the Merwede and Nieuwe Merwede and, 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, further 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 lagoon), 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 further west to rejoin the Noord into the Nieuwe Maas and to the North Sea.
The name "Rhine" from here on is used only for smaller streams further to the north which together once formed the main river Rhine in Roman times. Though they retained the name, these streams do not carry water from the Rhine anymore, 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 ("Crooked Rhine") and 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 Upper Germanic limes were built.
Tributaries from source to mouth:
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.
Just to the north of the Alpine Orogeny were highlands resulting from an earlier orogeny (Variscan) along similar lines. These highlands helped to divert the Rhine to the west; however, the Rhine's course is set by the Rhine graben, a rift that opened in the Eocene and Oligocene periods between the western Alps and the central Alps, caused by their moving in slightly different directions. The rift does not seem to be active now.
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 drained by the Rhône then.
By the early Pleistocene period, the Rhine had captured most of its current Alpine watershed from the Rhône, including the Aare. 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) to its watershed.
During the last Ice Age (~70,000-10,000 yr BP= Before Present), at the end of the Pleistocene, the lower Rhine flowed roughly west through the Netherlands and then to the southwest, through the English Channel, and finally to the Atlantic Ocean. The English and Irish Channels, the Baltic Sea and the North Sea were still dry land, mainly because sea level was approximately 120 m lower than today. At about 5000 BC, flooding and erosion began to open the English Channel. Most of the Rhine's current course was not under the ice during the last Ice Age, although its source must then 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 covered Scandinavia and the Baltic, Britain 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.
These events were well within the residence of man. Melt water adding to the ocean and land subsidence drowned the former coasts of Europe. The water is still rising, at the rate of about 1-3 mm per year. Further drowning is to come.
Rapid warming and change of vegetation to open forest began about 13,000 BP. By 9000 BP, Europe was fully forested. About 7000-5000 BP a general warming encouraged migration up the Danube and down the Rhine by peoples to the east, who may also have been encouraged by the sudden massive expansion of the Black Sea as the Mediterranean burst into it through the Bosphorus at about 7500 BP. At least one unsuccessful search for remains of villages on the floor of the Black Sea has been conducted.
Neanderthal sites are denser to the south, where open forest prevailed and the limestone terrain offered more caves as dwelling. The Rhine ran through an open tundra, where Neanderthals hunted big game, such as the woolly rhinoceros and the mammoth. Accordingly, open air Mousterian sites have been discovered in and around the Rhine valley.
Throughout the long history of Rome, the Rhine was considered the border between Gaul or the Celts and the Germans, even though the border often was violated, as when the Germanics crossed it and joined with the Celts to form the Belgae (descending to Belgium). Typical of this point of view is a quote from Maurus Servius Honoratus, Commentary on the Aeneid of Vergil (On Book 8 Line 727):
The Rhine in the earlier sources was always a Gallic river.
As the conflict between Rome and the Germanics 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, the Niederrhein and Oberrhein regions of the map included with this article.
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 14 AD and 180 AD 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. The legions were V Alaudae, a Celtic legion recruited from Gallia Transalpina, 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 Germans combined into the Alemanni. For a time the Rhine ceased to be a border when a union of all the west Germanics, the Franks, crossed the river and occupied Roman-dominated Celtic Gaul as far as Paris.
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 border has been and 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 was still a defensive barrier. The Germans fought especially hard to defend it. The Rhine is closely linked to many important historical events — particularly military ones — in the adjacent states. For example:
Rhine-Meuse-Scheldt delta | Rift valleys | Rivers of Austria | Rivers of France | Rivers of Germany | Rivers of Switzerland | Rivers of the Netherlands | Rhine basin
Ryn | Rhein | نهر الراين | Rhein | Рейн | Rin | Rýn | Renu | Rhinen | Rhein | Rein | Ρήνος | Río Rin | Rejno | Rhin | رود راین | Rhin | Ryn | Río Rhin | 라인 강 | Rajna | Rhein | Rín (fljót) | Reno | ריין | Rhenus | Reina | Reinas | Rajna | Rijn | ライン川 | Rhinen | Rhien | Ren | Rio Reno | Rhing | Rin | Рейн (река) | Rhine River | Rýn | Ren | Rein | Rhen | Рейн | 莱茵河