Control por redundancia cíclica

See also: the Loire

The the Loire is a long Fleuve of 1  020 kilometers, which makes some longest of France. It takes its source in Ardèche, with the Mont Gerbier de Jonc.

Its mouth is in historical Brittany (the part of its course between the Ingrandes-on-Loire and Nantes is called the Basse-Loire in the Pays of the Loire. It throws in the Atlantic Ocean in Loire-Atlantique through a Estuaire.

Its basin of 117  000 km ² occupy more than one fifth of the French territory.

The adjective meaning “relating to the Loire” east ligérien , according to the name of the Latin river in : Liger .

History

Scientists put forth the assumption that, in a distant past, the Loire continued towards North and ended up meeting the course of the the Seine, while existed another Loire taking its source in the area of Gien and moving towards the west. A geological incident, probably the folding of the Alps, would have supported a capture of the Loire séquanaise by the Atlantic Loire and would have thus diverted the river towards the west, giving the current Loire. The bed of the old Loire séquanaise is today occupied by the Loing.

Navigation

Formerly important axis of Navigation and Transport of goods until the middle of the XIXe century, the Loire is not navigable any more today for largest Bateau X only in its Estuaire, until Nantes approximately. It remains classified inland waterway interior (and managed by Inland Waterways of France) starting from Bouchemaine to Nantes, and also on two kilometers between Decize and Saint-Leger-of-Vines to ensure connection between the channels Latéral the Loire and of the Nivernais. One will note also the presence of a lock with small gauge on the stopping of the nuclear plant of the Belleville-on-Loire. It is the only lock on the course of the Loire.

The old boats were traditionally flat-bottomed (like any inland waterway vessel), with a mainmast and a square sail to take the wind prevailing of west from Nantes to Orleans, demolishable to pass under the bridges. According to their size, these boats named barge, barge, gabarot, warps, mahon, Fûtreau…

With these perennial boats coexisted of the boats designed for a single descent, sold at the end of the voyage like heating or timber, or re-used locally. These boats, built in fir tree in the area of Drill, took along coal inhabitant of Saint-Etienne and the products foréziens such as wines and ceramics to Paris or Nantes. Their traffic lasted of 1704 with 1860. They were named, according to their places of construction, saint-rambertes (or ramberte or salambarde) if they were built with the Saint-Rambert-on-Loire, or roannaises if they were built with Roanne.

Shipping with vapor

The first boat of this type on the river is launched in June 1822. It is called the Loire and is intended to make the shuttle between Nantes and Angers. From 1825, other boats go up thus to Orleans. Intended for the carriage of the people and the goods, they strongly compete with the traditional navy. They are primarily paddle steamers, flat-bottomed, with a tilting chimney (to pass under the bridges). Many accidents enamelled the river history, of which several explosions of boiler.

In 1837, the design of the boilers is modified, giving rise to the boats called Inexplosibles , whose first company is fixed at Orleans. They are long of forty meters with a draft lower than 20 cm. The boiler, power station, make it possible to drive two side paddle wheels. The Orleans-Nantes way lasts two days and the increase three. Upstream, the boat could join Nevers in two days additional.

The irregular flow of the river strongly limited circulation, in particular the increase of this one, which could be however helped by the towing of the boats.

In May 1843 opens the railway line Paris-Orleans. The non-explosible are then used to join the other ligériennes cities. The end of the year 1840 sees the arrival of the train with Tours, Angers, then Nantes, putting fine at the river transport of the passengers. The transport of the goods will survive some time, one of the last boats in service being the Fram which sailed until in 1918.

A reconstitution (not functional calculus) of a Inexplosible is visible on the quays of Orleans since the summer 2007.

The XXe century

Until 1991, tankers still went from Nantes t0 Bouchemaine, with the mouth of the Maine, close to Angers. Today, this commercial traffic completely ceased.

Rebirth of navigation ligérienne

Since the beginning of the years 1990, a powerful movement of renewed interest for this inheritance led the many associations, helped by archeologists nauticians like François Beaudouin, to as accurately rebuild as possible these old boats. Among the festivities on the topic of the Loire, place, every two years has, in Orleans a large gathering of these “old men gréments” of the Loire, in September.

The royal River

See also: Loire Valley

The valley of the the Loire located between the Sully-on-Loire and the Chalonnes-on-Loire was classified in 2000 by UNESCO World heritage of humanity. The Loire is sometimes called royal Fleuve because of presence of many castles in this portion.

Last “wild river”?

In spite of several stoppings and important protections side against the risings (of the turcies or raised), the Loire is often presented like the “only large wild river” surviving in France: it is also a “kingdom” of sumptuous landscapes and natural environments very rich. But this name, according to the archeologists nauticians and other historians, is very abusive: the Loire is a river “civilized” since Antiquity, from its privileged position, with the Rhone, in the French isthmus between the worlds Mediterranean and Atlantic. Very early she knew installations to support navigation and to protect the bordering populations from her legendary risings. The Loire generated a civilization ligérienne which is clean for him, with its traditions, its know-how, its habits, its speech, even if today, with the disappearance of its navigation, this identity is perceived in a less obvious way. To speak about the Loire as of a “wild river of aspect” would be more suitable.

The entirety of the river was registered like Community Site of Importance of the Réseau Natura 2000 under the two directives “Birds” and “Habitat”, for the protection of its fauna and its wild flora, of its Biodiversité, its ecosystem S as well as crossing points of the migratory species.

Hydrography

Between source and Orleans

The Loire takes its source in the east of the Massif Central, with the southern foot of the Mont Gerbier de Jonc, in the Holy-Eulalie commune ardèchoise of , with 1  408 m of altitude. It is in the beginning only one simple net of Eau, and it would be righter of speaking about the sources of the Loire because the river is at the beginning only one small multitude Ruisseau X which meet gradually.

Very quickly, it meets its first Affluent, the Aigue Negro. The river runs then towards the west, then quickly towards north while crossing the Massif Central through several throats. Arrived to Saint-Victor/the Loire, it emerges in the plain of the Forez where it can make a first pause before attacking the threshold of Neulise, primarily of Porphyre. After the crossing of the throats of Villerest, it arrives at Roanne and will not consequently meet any more any mineral obstacle. Its course assagit and slows down, and it digs its bed in sands and clays. Its Confluent with the To combine with double Nevers its size (To combine It could even be the principal course, and the Loire its affluent, according to the fluctuations of their respective flows). It is directed then towards the North-West to fork finally towards south-west after Orleans. At the Pouilly-on-Loire, the bridge which makes it possible to connect Pouilly to the Département of Expensive the locates halfway between the source and the mouth.

Towards Orleans

In this zone, the minimum flow is primarily underground (the Loiret being makes of it only a Résurgence river). This configuration is responsible for certain collapses in the bed itself (“ moving sands ” responsible for much of drownings) or on the level of its banks ( bîmes ). The course is divided on certain levels into reads major or the large Loire (northern side) and reads minor or the small Loire (southern part). This division is artificially maintained by dams submarines parallel with the flow: the duits (or the dhuis ).

The mouth

The Loire throws in the Atlantic Ocean by an estuary located at the level of Saint-Nazaire (Loire-Atlantique). In this estuary, the presence of an emerged small island, the “Bench of the Block” located opposite the port of Mounting block-of-Brittany returns the increase of the ships to the maritime Loire (section St Nazaire-Nantes) very delicate. A channel, a 13 m permanently depth, is maintained. The estuary shelters the famous Chantiers of the Atlantic for the manufacture of steamers of cruising (Sovereign off the Seas - Queen Mary II, etc). A majestic bridge makes it possible to cross the estuary and thus to connect the North and the South of the Loire.

Principal affluents

The principal affluents of the Loire are, starting from its source:

  • the Padelle (G)

  • the Gazeille (D)
  • the Terminal (G)
  • the Arzon (G)
  • the Lignon of Velay (D) - 82 km
  • the Ance (G)
  • the Semène (D)
  • the Ondaine (D)
  • the Bonson (G)
  • the Furan (D) - 36 km
  • the Vizezy (G)
  • the Pond (G)
  • the Ghent (G)
  • the Coise (D)
  • the Lignon of Drill (G)
  • the Aix (G)
  • the Lourdon (G)
  • the Renaison (G)
  • the Oudan (G)
  • the the Rhines (D) - 60 km
  • the Jarnossin (D)
  • the Sornin (D)
  • the Teyssonne (G)
  • the Arçon (G)
  • the Arconce (D)
  • the Arroux (D) - 120 km
  • the Sorme (G)
  • the Vouzance (G)
  • the Roudon
  • the Besbre (G) - 97 km
  • the Somme (D)
  • the Engièvre (G)
  • the Aron (D) - 105 km
  • the Acolin (G)
  • the Ixeure (D)
  • the Collâtre (G)
  • the Nievre (D) - 53 km
  • the To combine (G) - 410 km
  • the Aubois (G)
  • the Vauvise (G)
  • the Nohain (D)
  • the Egg (D)
  • the Cheuille (D)
  • the Trézée (D)
  • the Notreure (G)
  • the Aquiaulne (G)
  • the Bonnée (D)
  • the Oussance (D)
  • the Bionne (D)
  • the Loiret (G) - 12 km
  • the Mauve (D)
  • the Beuvron (G) - 115 km
  • It Cosson (G)
  • the Cisse (D) - 81 km
  • the Choisille (D)
  • the Bresme (D)
  • the Expensive (G) - 365 km
  • the Roumer (D)
  • the Indre (G) - 276 km
  • the Vienna (G) - 359 km
  • the Thouet (G) - 140 km
  • the Authion (D) - 85 km
  • the Maine (D) - 12 km
  • the Aubance (G)
  • the Tailboard (G) - 90 km
  • the To drink of Champtocé (D)
  • the Èvre (G) - 89 km
  • the Twisted Boire (D)
  • the Havre (D)
  • the Divatte (G) - 28 km
  • the Erdre (D) - 92 km
  • the Separate Nantes (G) - 125 km
  • the Chézine (D) - 21 km
  • the Acheneau (G) - 25 km
  • the Brivet (D) -? km
NB: D=Droite G=Gauche

Hydrology

The average flow of the Loire is very irregular. It is, over one year, of 350 m ³ /s with Orleans and of 900 m ³ /s with the mouth. However, it can sometimes brutally exceed the 2  000 m ³ /s for the high Loire and 7  000 m ³ /s in the low Loire in Raw period of . In summer, a medium flow of 10 m ³ /s in Orleans is not rare. This irregularity of the flow makes that the major part of the river is not navigable.

The flow is partially controlled by three stoppings:

  • those of Grangent and Villerest on the Loire;
  • that of Naussac on the To combine.
They allow the reserve of water to chop the risings and salting out to maintain a flow sufficient, in particular in order to allow the cooling of the four nuclear plants located on the river (the Belleville-on-Loire, Dampierre-in-Burly, Saint-Laurent-Nouan and Chinon).

These stoppings, and in particular that of Villerest which drowned splendid throats, theoretically allow a protection against the risings the constructions allowed in floodplain with a certain kindness by a mayor who was then also president of the EPALA. It is rather illusory…

Risings of the Loire

They can be of type Cevennes upstream by brutal downpours or of oceanic type .

They are known of long time, justifying the construction of dams as of the 12th century, extended by Louis XI to Orléanais and Touraine.

The greatest risings, in the area of Orleans, took place in June 1856 (level maximum in Orleans to 7,1 m with flow with 6  000 m3 with the nozzle To combine), in 1866 (level 6,92 m), in 1846 (level 6,78 m). The most important rising at the 20th century is that of 1907 (level 5,25 m). Previously, those of the 1707 and 1790, of the same order of importance, were the risings of reference.

The rising of 1856 remains still nowadays the rising record and of reference for town and country planning. It covered close to 100  000 hectares, destroyed nearly 23 km of dams and causing the death of about thirty people only in the department Maine and the Loire. Many cities were partially submerged: Blois, Turns, Trélazé, etc… In this last commune, the career of the Salte quarries was absorbed causing the stop of the production lasting several months. The emperor Napoleon III then made a visit on the spot of the catastrophe. This visit near the disaster victims, had also political thought backs (cf riots of Marianne in this commune one year earlier). Let us note however that with the upstream of the confluence Allier, this rising of 1856 is clearly below those of 1846 and 1866, that is to say of a level are equivalent to that of 1907, which is already not badly.

Many old houses comprise marks of raw on their walls. A campaign to remember the catastrophe was then undertook depositor of many commemorative plaques on the zones flooded in 1856.

January 4th, 1994, Michel Barnier, Minister of environment for the Balladur government, announces the Plan the Loire Life size, a global level of installation of the Loire aiming at reconciling the safety of the people, environmental protection and economic development.

Crossed main cities

The the Loire gave its name:

See too

Random links:Wavrans-on-Ternoise | Alexis Nicolaevitch of Russia | Castle-in Olonne | Tintry | Of agri will cultura | Contrôle_par_redondance_cyclique