The Rhone

The the Rhone is a Fleuve of Europe. Length of 812 Kilometer S, it takes its source with the Glacier of the Rhone in the the Alps Suisse S (231 km) and finishes its course in the delta of the Camargue in France (581 km) to throw itself in the Mediterranean. It feeds in the passing the Lac Léman.

After the the Nile, the Rhone has the largest flow of all the rivers running out in the Mediterranean. Throwing itself in a sea without tide, the river formed a delta with arms which moved west overall is during the historical period. From now on dammed up, its delta is fixed except at the time of exceptional risings such as for example in 1993,1994 and 2003.

It is sometimes identified with the Éridan which are the name of a god river of Greek mythology, wire of Océan and of Thétys.

Semiology

The origin and the significance of the name of this river are still prone to discussion. According to the Celtic assumption Rhodanus or Rodanus would come from Rhôdan , which means “to turn highly”; but the form of this name appears Greek than Celtic, and Pline Old the in its Natural history estimated that the Rhone draws its name from Rhoda or Rhodanusia , colony of Rhodiens built formerly with the one of its mouths, around Acute-Dead.

Geography

The Rhone is born above Gletsch in the solid mass the Saint-Gothard, in Suisse. Its source is consisted melt waters of the Glacier of the Rhone which fills the top of the Vallée of Conches, under the collars of Furka and the Grimsel. Powerful torrent of mountain, it runs initially in a East-West direction throughout the Vallée of the Rhone; with Martigny its valley strongly narrows and it goes up towards north before being thrown in the Lac Léman; it comes out from it with Geneva, where it receives the Arve, then penetrates in France; the layout of its course is sinuous to the surroundings of Lyon or it receives the the Saone, its longer affluent; in this section, the valley separates the solid masses alpine (left bank) and Jurassic (Right Bank). Starting from Lyon, it runs towards the south, between the Alps and Massif Central, to throw itself by the delta of the the Camargue in the Mediterranean.

Principal affluents

Switzerland

France

Tributary major (more than 100 m ³ /s)

Other affluents (less than 100 m ³ /s)

Main cities bordering the Rhone

Hydrology

Mode

The hydraulic mode of the Rhone is characterized by maximum the autumnal related ones to the Mediterranean rains, and spring because of the cast iron of the ices. The winter often has constant flows but less marked and the minimum hydraulic mode is estival.

Qualified “odd river a long time”, because of these powerful risings (more than 11.000 m ³ /s with the downstream), it is of use of speaking today about “river overcome” since general installation by CNR. The risings of 1993-1994 and 2002-2003 showed, if it of it were need, that hydroelectric installation manages only the ordinary flows, but does not prevent to in no case the formation of great risings similar to those of the 19th century.

The Rhone is characterized by the diversity of its catchment area:

alpine contributions constant between May and July (cast iron of snows and the glaciers)
oceanic contributions of winter, with slow risings (the Saone)
Mediterranean and Cevennes contributions with violent risings of autumn and severe low water levels of summer.

It results from it a very complex hydrological mode, and a very great diversity in the formation of believed and their unfolding. The following types of rising are distinguished:

oceanic risings, in which the Saone plays a paramount role
the extensive Mediterranean risings (January 1994), with a strong contribution of the Mediterranean affluents of left bank (the Durance, in particular)
Cevennes risings (September 2002) with a paramount role of the Mediterranean affluents of Right Bank (Ardeche, Cèze, Gardon)
generalized risings (type 1856)

The medium flow interannual of the raised river with Beaucaire is of 1.700 m ³ /s (given 1920-2005). It is considered that the Rhone is in rising as soon as its flow exceeds the 5000 m ³ /s.
Le recent record measured date of December 2003 with a flow announced initially to 13000 m ³ /s in Beaucaire. The flow since was revised with 11500 m3/s + - 5%. See also National company of the Rhone and town hall of Arles.

The services of the State, for the evaluation of the risk of flood (development of the Prevention plans of the Risks of Flood, PPRi), regard as raw reference the rising of 1856, estimated at 12500 m3/s with Beaucaire: it would be thus a little stronger than the rising of 2003.

The largest historical rising is probably that which has occurred in November 1548, even that of 580. The Raw millenium, as for it, is estimated at more than 14000 m ³ /s (between 14000 m ³ /s and 16000 m ³ /s, according to the authors, with a consensus more marked for 14000-14500 m ³ /s). The Rhone is that of the five French rivers whose flow is highest.

The delta of the Rhone, initially before the 13th century then until the 19th century

Principal historical risings (to be supplemented)

Above all, work of the historian George Pichard on the chronicles of believed of the Rhone since the Middle Ages is to be announced

Before the year 1

Towards 175 av. JC: important believed of the river recovers a broad part of the agglomeration of Arles and causes the irremediable destruction of the southern districts. These southernmost peripheral districts are abandoned thereafter during two centuries.

2nd century

Towards 150: traces of important believed in Arles

3rd century

Towards 280: historical sources indicate an important rising to Lyon devastated by a flood. Archeology confirms with Arles the destruction by water of a Roman habitat at the end of the 3rd century.

4th century

346 : believed generalized of the Rhone

6th century

579 or 580 (more probably in 580): believed of autumn with flood in Lyon and Arles.

has Lyon, Gregoire de Tours pays: At the beginning of October, after two days of continual rains, the Rhone and the Saone entered in rising. Thing which had never occurred, the two rivers met in the middle of the peninsula and formed a current if violent one that part of the walls of the city was reversed, from where one can judge number of houses which last being pulled by water.
has Arles, the Roman circus is abandoned after this catastrophe.

7th century

618 : probable rising with floods

9th century

808 : believed of spring? This year, the winter was very “soft” and very pernicious. One was afflicted with his continuation with terrible floods
809: believed of winter generalized? In 809, the flood exceeded all the known floods. It carries the harvests of the bordering fields and forced the inhabitants of the edges of rivers to seek a refuge on the heights. The abundance of the rains was the cause. It reached its apogee on December 28th.
821 or winter 821 - 822: believed generalized in France. There was in France a so great abundance of rain which the fruits of the ground were lost by it and which one could nothing sow next spring. The rivers left their bed and water was spread with far in the campaigns.
822 : believed generalized at the end of the winter or at the beginning of spring
868: believed historical generalized of the rivers following ceaseless rains

13th century

1226 : believed of autumn (at the end of September) and floods in Avignon few days after the rendering of the city in the troops of the king Louis VIII which besieged the city since the beginning of the summer. With a margin of a few days, the city had been saved.

14th century

1308 : a letter of the count de Provence Charles II evokes the destroyed cultures, the carried bridges and the cattle drowned following a rising.
1345 : believed and catastrophic floods
1352: believed and floods. With Arles, following the floods of 1352, the Chapter cannot be correctly supplied any more (according to a text of October 5th, 1352)
1353: catastrophic floods
1358: catastrophic floods
Between 1368 and 1373: believed badly dated, probalement in 1372.
1396 : believed of November 14th, 1396 announced by the chronicler arlésien Bertrand Boysset.
1398 : believed of October announced by the chronicler arlésien Bertrand Boysset.

15th century

1401 : believed of December announced by the chronicler arlésien Bertrand Boysset.
1404 : believed of February announced by the chronicler arlésien Bertrand Boysset.
1424 : believed of end of spring (semi June).

With Tarascon it is reported that " June 16th, 1424, of the floods of the Rhone, put the city into large péril" . At the end of this same year 1424, the council and the Syndics of Tarascon are concerned with make repair the breaches open in the liftings of the Rhone).
In the Camargue, at least 80% of corns are destroyed by the floods.

1426 : believed of spring with floods in the Camargue.
1432 : believed of spring with floods in the Camargue.
1433 : believed of autumn (at the end of November). Accounts bring back the details of the flood of Avignon: “after several days of continual rains, the Rhone, the the Durance and the Sorgue had overflowed and flooded the low districts of the city. November 29th, water reached the door of the vault of Penitent the Gray. Water withdrew on December 1st.”
1442 : believed of spring (April) with many damage listed in the countryside arlésienne.
1471 : believed of autumn described in Lyon and in the area of Avignon. For Lyon, a text mentions: “… given granted to Pierre Dirty, farmer of the bar of the bridge of the Rhone, on the price of its lease. In its request addressed to the consulate Pierre Sales explains that " the passaige of the aforesaid the bar esté of quite small value " because of the flood which took place in October (1471), of…”

16th century

1544 (or 1548 or 1554?) : believed of autumn (about on November 13rd); floods generalized in the south of Avignon.

In November of the year 1544, it rains abundantly in Provence, causing a flood which made reverse part of the walls of the town of Avignon, unearthing the bodies of the cemeteries. The Rhone overflowed so much, that since the Durance to the sea, all the countryside does only one with it, at such point, Honore Bouche says to us that one can go by boat of Castle-Fox to Eyragues or with Saint-Rémy.
Believed of November 12th, 1548, quoted by Jacques Bethemont at the time of a conference (Avignon 1994). on this date, the rising reached 8,45 meters on a scale Saint-Bénézet (Avignon), against 7,83 meters in 1856… On this basis, Mister Pardé evaluates with 16000 cubic meters a second the flow of the thousand-year-old rising.
In the Camargue about 1550, one brings back a defluviation of the Small-Rhone to the level of Sylvéréal following a large rising. The current layout goes back to this time.

1556 : believed and catastrophic floods
1564: autumnal rising (at the end of November - at the beginning of December) in Arles. " On the way of the return, the royal caravan (Charles IX and its mother Catherine de Médicis) was immobilized in Arles by a rising of the Rhone. It entered, the Thursday the 16th, in Arles, where water retained it during three weeks. It left the city on December 7th… "
1570 : believed and catastrophic floods
1573: believed and historical flood of the Rhone close to Avignon (Caderousse)
1580: believed and catastrophic floods
1581: believed and catastrophic floods
1583: estival rising (!). August 24th, 1583, a brutal rising and devastator involves the collapse of part of the ramparts of Arles
1587: believed and défleuvement of the Rhone in its delta. A large flood will upset the bed of the Rhone of Grand Passon and will create the Canal of Japan (or Arm wrestling)
1593: believed of the large Rhone Easter day before (March-April)

17th century

1602 : believed and catastrophic floods
1614: believed and historical flood of the Rhone close to Avignon (Caderousse)
1638: believed announced to Tarascon
1647: floods (to be checked)
1651: floods (to be checked)
1653: floods (to be checked)
1657: floods (to be checked)
1658: floods (to be checked)
1674: believed of catastrophic autumn (November) and floods

Flood announced to Avignon;
Gros damage on work of drying of the marshes between Arles and Tarascon.
In 1674, the flood was so terrible that in 1683, whereas another major flood occurred, repairs of the damage of 1674 were not completed yet, which involved many lawsuits, in particular with the community of Tarscon.

1678 : believed of spring announced on April 16th, 1678
1679: believed and catastrophic floods
1683: floods
1688: floods (to be checked)
1694: believed of autumn (about on November 15th). The bridge of Arles is carried on November 15th: “On November 15th, 1694, the bridge of Arles resisted a great rising but, by roof of bad luck, that of Tarascon did not resist and its remains, carried by the current, ran up against and broke the first.”
1698 : floods (to be checked)

18th century

Between 1705 and 1719, raw and quasi annual floods

1705: believed of autumn (October) and floods
In 1705, water of the Rhone entirely destroys the works of drying around Arles.
1706 : believed of winter (January) and floods
1708: believed and floods (winter, spring, both?). In its Memories, Louis Pic says that in the summer 1708, the floods and heats fevers caused: “more half of the inhabitants were attacked, of kinds which they gave death to a great number of people”
1709: believed of spring after the hard winter 1709. In March 1709: “in a time that the country (the Camargue) is all flooded and that most of the inhabitants deserted”
1711: believed of winter (at the beginning of February) and floods.

With Lyon, the Rhone and the the Saone mèlent their water on the Place Bellecour (February 11th) and cause immense disasters.
In the delta of the Rhone, this rising causes a change of the course of the river: “in 1711, following a particularly important rising and because of the distraction of a eygadier, the Rhone changes once again bed giving up the layout of the Rhone of the Arm wrestling which becomes a secondary arm which is not long in being clogged.”

1713 : believed and historical flood of the Rhone close to Avignon (Caderousse)
1715: believed and catastrophic floods
1719: floods (to be checked)
1740: floods (to be checked)
1747: believed and catastrophic floods
1748: floods (to be checked)
1749: floods (to be checked)
1754: believed and catastrophic floods
1755: autumnal rising (November 30th - December 1st).

has Arles the dimension reaches 5,88 Mr.
With the Saintes-Maries-de-la-Mer, this rising is combined with an elevated level of the sea which causes the destruction of the country: " it acts at the beginning of a size of the Small-Rhone of exceptional width, following strong rains having caused the snow melt precociously fallen on the back mountainous country. And soon, by violent storm of South-east the sea immediately threatens the City and the soil, without meeting defense efficace" .

1760 : floods (to be checked)
1763: floods (to be checked)
1765: floods of end of spring? -
1774: autumnal rising?
1786 : floods (to be checked)
1788: autumnal rising?
1790 : believed of spring
1791: believed of winter and floods (in particular in the Camargue)

19th century

1801 : believed of spring (about on March 24th) and floods.

has Avignon, coast of 6,95 m
has Arles, coast of 5,27 m; in this city, a drawing of E. Tassy, preserved in a particular collection, represents the current Voltaire place and the district of the Cavalry flooded and covered with boats.

1810 : believed of spring (the 25- May 26th) and floods. Dimension 4,91 m in Arles on May 26th, 1810 (another source indicates 5,13 m)
1811: believed of catastrophic springs (May) and floods. In Arles coast of 5,38 Mr.
1826: historical flood of the Rhone close to Avignon (Caderousse)
1827: believed of catastrophic autumn (October) and floods - has Arles, coast of 5,10 Mr.
1840: believed of autumn (at the beginning of November); flow estimated at 12000 m ³ /s.

the rising of November 1840 was caused by a succession (4 on the whole) of torrential Mediterranean downpours, including one at least accompanied by torrential oceanic rains. It is “the weather event most imposing and most disconcerting which ever occurred in the basin of the Rhone “(Maurice Pardé) .

the rising is very strong upstream of Lyon and exceptional downstream because of the contributions of the the Saone. In Lyon, during all November, center of the east city under water; 600 houses collapse!

has Avignon, the rising of the Durance, is concomitant with that of the Rhone which reaches in this city the level of 8,65 Mr. the rising of November 1840 would thus constitute the strongest rising known with that of 2003, downstream from Avignon.

More in the south, the rising is reduced because of the many breaches in the dams of Gard, in particular with Bellegarde, and of Tarascon. With Beaucaire, the east coast measured to 6,85 Mr. With Arles, it is not established any more that to 5,05 Mr. N the other hand all the valley of the low Rhone is devastated.

the the Camargue is flooded. November 3rd, 1840, the delta, of saline of Acute-Dead (Peccais) until Wearing of Goat, is entirely submerged. Acute-dead must close the doors of the city not to undergo this same fate. the large river which had just broken its dams, reconquered its old field and bathed the walls of the city suddenly transformed into island; the doors were closed. During several days, the largest boats of the Rhone came to accost the ramparts like genuine quays, and could thus supply the population protected by her enclosure against this enemy from another nature.

1841 : believed of autumn (October) with floods. on October 26th, 1841, it occurs terrible floods which carry their devastations on the Camargue.

1843 : believed of autumn (November). With Beaucaire the measured level is higher than that of 1841. Saline of the Acute-Dead ones are still flooded

has Avignon, coast of 7,04 m

has Arles, coast of 5,15 Mr.

1846: believed of autumn (October) - has Arles, coast of 5,04 Mr.

1856: believed of spring (at the end of May); flow estimated at 12000/12500 m ³ /s.

" The rising from May-June 1856 was simplest and most brutal of the known general risings of the Rhone (before that of December 2003). It is about the largest known flood of the 19th century in the south of Bellegarde" .

has Tarascon, the rising reaches the flow of 12.000 m ³ /s and the 8,5 height m coast. May 31st with Beaucaire, it is measured to 7,95 Mr. With Avignon, the level reaches 7,95 m (another source indicates 7,83 m on the scale of Saint-Bénézet) and 5,58 m with Arles.

on June 1st the fall starts in Arles, but the damage is immense: June 1st, 8 hours 37, evening. - The Rhone dropped of almost 2m since midnight. This fall arrived too late; 4 dams were broken in various points. The the Camargue is covered with 2 or 3m of water. The plain, since Tarascon to the sea, is flooded; approximately 100.000 hectares, including 60.000 in culture, are under water. All harvests are lost. In the town of Tarascon, water rose with 3 or 4m. We are obliged to send of Marseilles the bread necessary to the inhabitants. It is probable that in the Camargue, most of the cattle is drowned. .

has Avignon, on June 3rd, 1856, the flood carries part of the ramparts between the door St-Roch and the St-Dominique door.

has Lyon, the damage are very important. The rising causes enormous damage in the territory of left bank in full period of construction and results in the death of eighteen people in the commune of the Guillotière.

the photographer Edouard Baldus, at the request of the administration of the Art schools carries out a report (probably one of the very first illustrated reports) on the floods devastators of the Rhone, with Lyon, Avignon and Tarascon. We also have the stereotypes carried out by Louis Froissard photographer of the Municipal service of the roadway system of Lyon.

1889 : believed of spring (April) and flood.

has Arles, the painter Vincent van Gogh announces in one of his letters (N°588 - of April 30th, 1889) a flood of the Rhone which causes damage with its apartment and its work stored there.

Always in Arles, an engraving of Gérardin in the Illustrated Monde represents the avenue of Tarascon flooded with height of the current parish of Trébon, with the people helped by boats.

1896 : believed of autumn (November). November 2nd, 1896 a rising is announced to Sablons (Isere)

Since the beginning of the 20th century

1928 : believed of winter (February). February 17th, 1928 a rising is announced to Sablons (Isere)
1935: believed of autumn (November); flooded districts of Avignon
1936: believed of winter (January); again flooded districts of Avignon
1993: believed of autumn (October) in the Camargue; flow estimated at 10000 m ³ /s (9800 m ³ /s raised in Beaucaire). Towards Saint-Gilles, the dams yield in 14 places and 13.000 hectares and 450 houses are submerged.
1994 : believed of winter (January) in the low valley of the Rhone and floods in the Camargue; flow estimated between 10500-11000 m ³ /s (almost 11000 m ³ /s raised in Beaucaire). In two places, the dams still yield (2 000 hectares submerged and 45 flooded houses)
2000: believed and floods in October in the Canton of Were worth, it is regarded as " exceptionnelle" by the specialists with medium flows higher than that in 1993
2002: believed of autumn (at the end of November).

has Tarascon, a flow of 9500 m ³ /s is measured.
has Avignon the island of Bartelasse is flooded as well as the surroundings of Saint-Gilles (about on November 27th)

2003 : believed of autumn (at the beginning of December). On this date, it is about the greatest historical rising measured with a instantaneous flow of 13000 m ³ /s on December 4th with 03:00 with Beaucaire. The National company of the Rhone (CNR) in his summary report indicates a rate per hour higher than 12500 m ³ /s. the damage are particularly dramatic in the plain of the low Rhone (in the south of Tarascon) in consequence of rupture of the dams.

the dams yield to north Arles and all the agglomeration built in the North-East of the city since 1900 is under water which is blocked in the south and the east by the canal banks of Viguerat. For the only town of Arles the French federation of Insurances (FFA) enters more than 8.000 disaster victims.
More in the south, other dams yield downstream from Fourques on Right Bank of the Small Rhone and the Petite Camargue until Acute-Dead is submerged as during the floods of November 1840.

Morphology and river dynamics

The Lake Léman induces a total cut between the High Rhone and the Rhone downstream as regards sedimentary load.

The Rhone with the upstream of Léman

History of protection against the risings in Switzerland Origins until the 19th century Daniel L. Vischer HTTP: /assets.wwf.ch/downloads/histoire_protection_contre_crues__suisse.pdf

The Rhone with the downstream of the lake Léman

The diversity of the basin is reflected on the conditions of production and food of the Rhone in sedimentary load: geological diversity of the basin, heritage of the glacial formations, contrasted morphoclimatic conditions of degradation of the basins… The installation of the Rhone entrusted to CNR for the needs for navigation and the hydroelectric production was almost concluded its. Only remain with free current the short section on both sides of the confluence of the Ain (abandonment of the project of installation of Loyette) and the Rhone with the downstream of Beaucaire. The succession of 20 installations completely reorganized the Rhone on the remainder of the linear one.

General morphological characters

The natural river dynamics of the Rhone and its affluents, and the structure of the slopes which is the image, is strongly marked by the heritage of the last glaciations.

Upstream, to Lyon for the Rhone (and Valence for Isere), the quaternary glaciers (the glacial maximum last approximately 18000 years ago) left alternations of surcreusées zones (umbilical points) and zones prominent (bolts). The umbilical points are occupied by glacial lakes when they were located at the variation of the principal rivers capable of the réalluvionner (Annecy Lake, lake of Le Bourget). On the other hand, if they were located on an axis of major flow, they were alluvionnés in whole or part, but without the continuity of the transit of the gravels always being able to be restored: the Lake Léman is very only partially alluvionné by the High Rhone, the plain of Brangue it Bouchage, upstream of Lyon, is alluvionnée, but the slope was there still weak (zone of marsh).

Downstream, the fast increase of the marine level at the end of the last glaciation some 10000 years ago (gone up of 120 m: Transgression flandrienne) forced the river to deposit its alluvia (formation of the Camargue): the gravels still do not arrive to the sea, and settled at the entry of the delta. The majority of the affluents had evil to follow the increase of the level of the river: they deposit their coarse alluvia at the entry of the plain of the Rhone and end in a bed with mobile meanders (Ouvèze, Aygues, Ardèche, Cèze, Gardon).

Between these two sectors, the Rhone shows a profile more or less smoothed with a low thickness of alluvia, a close substratum and relatively strong slopes.

The structure of the slopes

The High-Rhone presents a total decrease of the slope (except for a nonrelevant sector of throats for the overall analysis) associated with a tendency to aggradation of the bed and the reduction of the basic load, until interruption of this one between Guiers and Sault-Brenaz (slope going down locally below 0.2 ‰). The contributions of Ain and a sedimentary refill in the terraces würmiennes supports a strong activity upstream of Lyon associated with a strong slope (0.8 ‰). A tendency to aggradation at the entry of Lyon and the liquid contributions of the the Saone lead to a weaker slope on the third upstream of the Low-Rhone. The central third is characterized by a strong slope (higher than 0.8 ‰ locally) associated with frequent rock exposures, but which do not make threshold: one is there in extreme cases of the structural slope (imposed by the structural framework and not by balance between transits solid and liquid: “passive transport”) and of a morphological slope (reads freely digressing formed of alluvia, in permanent exchange with transport by haulage: “active transport”). The slope decreases then regularly to the delta.

Coarse contributions and fine contributions

The sedimentary Transit covers a broad material range. Two means of transport classically are distinguished: transport by haulage on the bottom of the coarse alluvia and transport in suspension of the fine sediments.

When it is a question of including/understanding the morphological evolutions of the Rhone, the distinction haulage/suspension is fundamental. The transition between the two means of transport is in general in rather coarse sands (between 200µ and 1mm). On all the course of the Rhone, they was the gravels and rollers which, before great installations, constituted the sedimentary transit “active”, i.e. which worked the bed of the river. The fine sediments (silts and sands) transported in suspension played a secondaries part in the alluvial margins.

The gravels and rollers did not reach the sea: they contributed to aggradation at the entry of the delta. The gravel contributions are unimportant today.

The silts and clays are carried far from the coasts and contribute to pelagic sedimentation.

Ultimately, only sands play an active role in the sedimentary dynamics of the littoral. The average diameter of the sediments is generally included/understood enters on the littoral. Sands which take part in the dynamics of the littoral are transported in suspension in the Rhone, including same in the deltaic part.

Factors of disturbance of river dynamics

Installations for navigation

From the middle of the 18th century, insubmersible dammings up are built by the residents. They remain however very few until about 1840. Following the serious floods of 1840 the “Special service of the Rhone is created”. On this date begins systematic construction from main dikes in the plain of flood.

In parallel, a principle of installation of the channel is adopted to improve the conditions of navigation according to a sinusoidal layout with large radius of curvature. Dams submarines are built along concave banks. The systematic stopping of the secondary arms is committed. Sometimes, the double objective of protection of the grounds and fixing of the navigable channel led to main dikes, as with Pierre-Bénite.

The law of 1878 declares public utility “work of improvement of the Rhone between Lyon and the sea”. Installations know a fast expansion then.

Girardon (1884) revolutionizes the designs of installation with free current. It modifies the use of ears plunging and drowned, the ground sills, the tenons and the cross-pieces according to a method which will be applied to the Rhone downstream successfully Poinsart, 1992. The “racks” result from the systematic association of the tenons to the low dams. The objective is of tending towards a channel of 150 m width in general, with a depth of water of 1.60m under the conventional low water level.

Last the realization go back to 1938. On this date, the installation of the Rhone with free current is about systematic between Lyon and Arles. Braiding disappeared with the profit from a single bed without latitude from divagation, provided with hydraulic appendices increasingly disconnected.

Installations CNR

Since 1899, the installation of Miribel-Jonage (dam Jons and factory of Cusset) constitutes the first exploitation of the Rhone for the hydroelectricity.

CNR is created in 1934. The general installation of the Rhone by CNR began in 1950 with the setting in water from Génissiat. It is about the only dam with a high head of the Rhone. Installation related then in years 1950/1960 to the central part of the Low-Rhone (falls of Donzère-Mondragon). It continued in the years 1970 by the installation of the thirds downstream and upstream of the Low-Rhone, then in the years 1980 by the installation of the High-Rhone.

Except for Génissiat, they are works low falls, entirely erasable, associated (except on Seyssel and Vaugris) with derivations. The derived flow varies from 700 m ³ /s on the High-Rhone to 2200 m ³ /s on the Low-Rhone downstream. It is on average 1,5 times superior with the module.

The installation of the Rhone for the hydroelectric production and navigation thus relates to it quasi totality of the linear one: only the section between Sault-Brenaz and Lyon (with the abandonment of the project of fall of Loyette) and the downstream of Vallabrègues to the Camargue are not concerned.

The impact of these installations on the transit of the gravels is related to two great factors: the disturbance of the mode of the slopes in reserves and the disturbance of the mode of the flows in the shorted-circuit sections.

In reserve

In reserves, the slope is zero or low for all the ordinary flows and the annual risings. There is only for the exceptional risings that the slope tends towards the angle of rest.

However the transport capacity decreases quickly with the slope. Generally, a reduction of 25% of the slope leads to a gravel transit 5 times less. A slope equal to half of the angle of rest practically corresponds to a slope of nontransport: the flow of beginning of drive is indeed more than triplet: it corresponds then to a flow exceeded 1 day every 10 years in general.

With the right of the stopping

When the flow of the Rhone exceeds the nominal capacity of derivation, the valves of the stopping are gradually open. The opening of the bottom outlets allows the hunting of materials deposited the immediate upstream of the stopping.

However, as long as it remains a pressure loss to the stopping, the slope upstream is lower than the angle of rest, and allows only one transit partial of the gravels until the stopping. The opening of the bottom outlets allows the evacuation of the sediments accumulated in front of the stopping, but not the transit of all the basic load upstream.

It is only when which the pressure loss to the stopping becomes negligible that one can truly speak about total transparency. The rising then ensures not only the transit of the contributions of upstream, but also the resumption of part of the sedimentation of reserve. This total transparency is assured only starting from the centennial rising.

In shorted-circuit the Rhone Old man

With little thing near, one can consider that the derived flow is constant (actually, the derived flow is decreased generally a little during the strong risings), except incident in the operation of the stopping. The major part of time, it remains in the Rhone Old man only the “reserved flow”, unable to transport sediments.

The flow frequency morphologiquement active thus is strongly decreased, which reduces of as much the transport capacity in the RCC (the shorted-circuit Rhone).

The high waters until the annual rising ensured before installation nearly 98% of the transit of the gravels. On the installation of Chautagne (the High-Rhone), the range of flow corresponding to frequencies from 20 to 130 days per annum (between 400 and 700 m ³ /s before installation) ensured the transit of 75% of the total transit. With the derivation of 700 m ³ /s, the Rhone Old man is today with the flow reserved (morphologiquement completely ineffective) for this frequency band. There is only for the rare flows (above 900 m ³ /s in the Rhone Old man, i.e. 1 day every 3 years) that the transit of the gravels is not very disturbed. But these flows are not very effective in term of annual statement of account. On the whole, only 1% of the natural transport capacity are preserved in the Rhone Old man!

On Donzère-Mondragon (the Low-Rhone), derivation (1980 m ³ /s) is proportionally weaker than in Chautagne. The effect of reduction of the flows is thus less, but the incidences remain qualitatively similar. The residual transport capacity covers 6% of the natural capacity.

Aggregate extractions

The material movements on the Rhone result from the various management styles of the sediments implemented on the river and its affluents. Generally, they are translated, is by coarse material extractions when their economic valorization allows it (they are then gravels - coarse sand to the roller), that is to say by displacements without extraction, of a place to another of the bed, fine materials (of fine sands to clays while passing by the silts). The extracted materials correspond to material taking part in transport by haulage, whereas the remobilized fine materials correspond to the type of materials taking part in transport by suspension.

Apart from the reasons of maintenance of the bed, the material extractions were historically justified by economic needs related to the realization for the installation of the Rhone, road infrastructures, and more recently of the platforms of power stations EDF or embankments TGV.

Today, the material movements, extractions or re-mobilization meet a need for management of the bed of the Rhone for the clean needs:

with navigation (maintenance of a navigable channel for a given gauge)
with the maintenance of works (stoppings, valves, locks, etc),
with the electric exploitation (energy dredgings with the restitution),
with protection against the risings (left downstream the affluents)
with the maintenance of the bed of the shorted-circuit Rhone (scouring of the benches, ploughland).

Annual average volume of gravels extracted on all Rhone downstream from Léman in the minor bed: 900.000 m3/an.

Annual average volume of fine materials remobilized in the minor bed: 1.100.000 m3/an.

Current operation of the Rhone

Sedimentary transit in suspension

Natural transit in suspension

The transit in suspension is fast. It is necessary to count less than 24 hours of transit on average for 100 km. The effects of deposit/taken again are relatively marginal (except naturally in the large basins natural it Léman… - or artificial). Under natural operation, the deposits in the wooded margins (which can reach several decimetres during a rising) are regularly taken again by the river by erosion of these margins at the time of the divagations of the sharp arm. The low current mobility of the Rhone supports an irreversible raising of these margins, as well as a reduction of the width of the principal bed in reserves. But the damming up of the river limits the width to which applies these evolutions, and thus volumes concerned. Under these conditions, the contributions of the Rhone to the the Camargue result directly from the production of the catchment area. It results from it that the evolutions of the Bassin pouring influence quickly and directly the contributions in suspension.

The natural transit could be estimated at 20 million tons per annum in the years 1950. It is possible that the transit reached 30 million tons per annum at the beginning of the 20th century, at the time of the demographic maximum in the Alps, which had supported a strong deforestation of the slopes.

Current transit

The contributions of the catchment area did not change to a significant degree since the middle of the 20th century: the state of the slopes, the development of the zones of gullying, the operation of the torrents evolved/moved little. On the other hand, dam traps significant volumes of fine sediments: Vouglans on Ain, Génissiat on the Rhone, Greenhouse-Ponçon on the Durance, Tignes on Isere, Sautet and Monteynard on Drac, Co.-Cross on the Verdon,… the fixing of the bed of the Rhone and some of its affluents also supported sedimentation in the alluvial margins. One can consider the contributions current at 10 million tons per annum.

Sedimentary transit by haulage

Natural transit before améangements

On the contrary, the transit by haulage is much slower. To fix the ideas, the time of transit is several decades for 100 km. The continuity of the transit by haulage before the great disturbances due to hydroelectric installations and the extractions is a satisfactory working hypothesis on much of sections moderated length, where the variations in altitude of the bed are negligible on a human scale. On the other hand, even before great work for navigation and the hydroelectric production, there was not continuity of the transit of the gravels on a basin scale like that of the Rhone. The times since the last glaciation (about 15000 years) indeed were insufficient so that the profiles longitudinally on such a scale reached a balance ensuring the continuity of the transit. Before installation, the continuity of the transit was thus stopped on the Rhone upstream of Sault-Brenaz, and was reduced in a very important way to the upstream of Lyon, like in Chautagne. It was the same in the downstream part of several affluents (Isere, Aygues, Ouvèze,…). Of upstream downstream, one had before installation the following orders of magnitude:

with the downstream of the lake Léman, the contributions were assured mainly by Arve (100 000 to 150.000 m3/an)
these contributions, supplemented by those of the Customs and of Trusting, settled gradually, while the slope decreased by 1 ‰ with 0.2 ‰: the transit was null in Sault-Brenaz.
with the upstream of Lyon, the resumption of the morainic deposits (glacial) and the contributions of Ain supported a strong slope with a constant transit (100000 m3/an). The major part of this transit settled at the entry of Lyon, in the sector of divagation of Miribel. The transit was not to exceed 30000 m3/an with the downstream of Lyon.
on the low Rhone, the transit gradually took again with the favor contributions affluents, to reach a maximum of about 400000 m3/an with the downstream of the Durance.

Current transit

The transit of the gravels was completely upset during the 20th century:

the contributions of the majority of the affluents were dried up, because of installations and interventions whose they were the object: stoppings, derivations, extractions). The Durance, Arve, To trust, which brought large volumes to the Rhone, hardly any more cart of gravels in their final part.
on the Rhone, of the important extractions took place also, which left important pits of extraction
in any event, the Rhone would have been today unable to transport the natural contributions: too weak slopes in reserves, flows too reduced in the shorted-circuit sections.

On the whole, one arrives paradoxically at new a " équilibre": almost not of contributions, almost not of transport.

The gravel transit hardly exceeds a few thousands of m3/an on the majority of the sections, with a maximum of a few tens of thousands of m3/an between Drome and Ardeche.

Dynamics of the bed

History of the Rhone

The Rhone is the only river connecting the Mediterranean to Northern Europe. It constitutes since the Rhodiens and the Phéniciens a major axis of circulation of the populations and goods. Element structuring in the organization of the territories, the Rhone leads also the men to be exceeded to overcome it and especially to cross it.

One thus finds traces of occupation as of prehistory. As of Antiquity, tin, the copper or the skins of north are exchanged against productions of the East and the Mediterranean (ivory, spices, fabrics…).

Front in August 218 J. - C., Hannibal crosses the Rhone with its army of 80.000 men and 37 elephants with an aim of crossing the Alps. The Roman army under the orders of Scipion being very close on left bank to the river, it prefers goes up along the river with sharp pace during 4 days to avoid it, preferring to face the enemy in Italy, on his territory.

At the time Roman, it becomes a way of commercial development. Later, the wine, the crockery and salt on the one hand, the weapons and the fabrics of other share borrow in opposite direction the Rhone-native furrow. The presence of the river allows the urban development like Arles, Avignon or Vienna which benefits from their geographical asset with crossed of the Rhone and the terrestrial and maritime axes of communication. Crossings of the river also take part in a way determining in the history of the cities and the territories. These bridges, of the Roman bridges to the current bridges, are also a formidable engine of evolution and technological advance.

Others

The Rhone gave its name:

with the French department of the the Rhone;
with the French department of the Rhone delta;
at the old revolutionary department of the Rhone-and-Loire;
with the French area the Rhone-Alps.

Regional names:

Arpitan : Rôno;
Occitan : Ròse;
high-Valaisan: The Rhone/Rotten.

Ecological and medical state

The river is officially recognized like Pollué by the French state at least taking into consideration Polychloro-biphenyl. report/ratio CEMAGREF history of the protection of believed in Switzerland HTTP: /assets.wwf.ch/downloads/histoire_protection_contre_crues__suisse.pdf

See too

List of rivers in the world
List of the rivers of France
Flows of the rivers French of the basin of the Rhone
the Camargue

External bonds

Given hydrological in real-time
tourist Guide of the Rhone
Given quantified detailed
Tourist Country Valley of Cèze - Coast of the Rhone

Random links:

Arthur Ashe | Bramaterra | If I were it | Amédée Geoffrion | The North-East of the Rio Grande C Sul