Canal de Garonne
From Wikipedia, the free encyclopedia
The Canal de Garonne, until recently called the Canal latéral à la Garonne, is a French canal dating from the 19th century which connects Toulouse to Bordeaux. It is the continuation of the Canal du Midi which connects the Mediterranean with Toulouse. Together they now form the Canal des Deux Mers which connects the Mediterranean Sea to the Atlantic Ocean.
Contents |
[edit] Geography
[edit] Description
The canal skirts the right bank of the Garonne, crosses the river in Agen via the Agen aqueduct, then continues along the left bank. It is connected to the Canal du Midi at its source in Toulouse, and emerges at Castets-en-Dorthe on the Garonne, 54km southwest of Bordeaux, a point where the river is navigable.
The canal is supplied with water from the Garonne by two routes:
- The Canal de Brienne in Toulouse
- The Laboulbène drain in Agen (underground)
With the exception of the five locks at Montech, bypassed by the water slope, all of the locks have a length of 40.5m and a width of 6m. The locks at Montech retained the old gauge of 30m.
Many bridges cross the canal including eighty-three overbridges. Many were rebuilt in 1933 to allow for the requirements of larger boats.
[edit] Canal Specifications
| Width | 18 m at water level |
| Total Length | 193 km |
| Number of Locks | 53 |
| Difference in level | 128 m |
| Mooring depth 2.2 m for a draught of | 1.80 m |
| Headroom beneath bridges and other structures | 3.60 m |
[edit] History
Despite being inaugurated in 1856, the Canal de Garonne has been thought of since ancient times.
[edit] Study of the project and origin of the Canal du Midi
Before the Canal du Midi was constructed, the passage between the Atlantic Ocean and the Mediterranean Sea was down the Spanish coast and through the Strait of Gibraltar. This route, more than 3,000 kilometres long subjected navigators to the risks of attack and storms.
Nero and Augustus in ancient times, then Charlemagne, Francis I of France, Charles IX of France and Henry IV of France all had an ambition to construct a canal which avoided the aforementioned detour. All of them asked for the idea to be studied, many projects resulted but none were realised. The greatest difficulty was in supplying sufficient water at the watershed between the Mediterranean and the Atlantic to ensure continuous navigation.
Between 1614 and 1662, under the influence of Louis XIII and Louis XIV,five projects were born but none solved the water supply problem. Then in 1662 Pierre-Paul Riquet, inspired by the theories of Adam de Craponne put into practice at the beginning of the same century by Hugues Cosnier for the "canal de Loyre en Seyne" (or "canal de Briare"), sought to bring water to the place which would be the canal du Midi (between Toulouse and Sète), at a watershed near Seuil de Naurouze, where water flows both to the Mediterranean and the Atlantic. His knowledge of the Montagne Noire and its watercourses led him to imagine a system of provision based on the diversion of water from many streams and rivers.
This enabled the transport to cross the watershed, but it still had to use the Garonne to reach the ocean and this presented more problems with floods and groundings as the size of cargo boats increased.
[edit] Construction of the canal
It is said that when Pierre-Paul Riquet built the Canal Royal du Languedoc (now known as the Canal du Midi) between Sète and Toulouse from 1667-1681 he had the idea of continuing the canal closer to the Atlantic: the future Canal Latéral à la Garonne. However the successive enlargements of the Château de Versailles and the poor record of Louis XIV emptied the kingdom's coffers and the project never materialised. For two centuries people had to be content with the navigation of the Garonne.
It was not until 1828 that a new survey was ordered, a survey completed in 1830. France was in its industrial revolution and it was vital for its development that better methods of transportation of raw materials were created. This was the purpose of the Becquey plan of 1821 to 1822. However it was only in 1832 that the state granted the concession in perpetuity to the private Magendie-Sion company owned by Sieur Doin. The act allowing the construction of the Canal Latéral à la Garonne envisioned the provision of water from the Garonne utilising the Canal de Saint-Pierre or the Canal de Brienne. However, Sieur Doin did not agree with these commitments, the state falling back on its rights raised the possibility of forfeiture of the concession in a new act of 9th July 1835 which fixed new construction dates. Sieur Doin died before the work started.
A third act in 1838 allocated a sum of 100,000 francs to the heirs of Sieur Dion and repurchased the parts of the project for 150,000 francs. The project was then taken back into hand by the state with the divisionary inspector of Bridges and Roads Jean-Baptiste de Baudre in charge and began in 1838 with a budget of forty million francs. Construction began at several points simultaneously with thousands of workmen building the 193 kilometres of canal and remarkable structures such as the famous Agen aqueduct.
In 1844, the section from Toulouse to Montech to Montauban was open. The canal was open for navigation to Buzet-sur-Baïse in 1853 and upstream by 1856.
[edit] The canal before 1970
The canal was completed at the same time as the Bordeaux to Sète railway which followed the same route. The first trains left Agen station in 1857.
In the beginning the railway did not compete with water transport but later the state conceded the canal's exploitation rights to the Compagnie de Chemin de Fer du Midi, the direct competitor of the boatmen. The railway company increased the levies on water transport such that when the concession was withdrawn in 1898 the damage was already done. Indeed between 1850 and 1893, water freight diminished by two thirds.
However, until about 1970, the Canal Latéral à la Garonne was still concerned mainly with the transport of goods.
[edit] The canal after 1970
In the years before 1970 the canal was upgraded to allow larger boats of the Freycinet gauge, to deal with increasing traffic on both the canals of the Canal des deux Mers. But it was a new kind of traffic which saved the connection between the two seas: river and canal tourism.
This developed enormously after 1970. Boats brought visitors to an exceptional site of natural and historical significance. In 1996 the canal du Midi was classed as a UNESCO world heritage site benefiting the connecting Canal de Garonne as well.
More than half the tourism activity is concerned with the hiring of unlicenced boats: nearly 1000 boats travel between the Mediterranean and Atlantic and vice versa each year. The professional boat services include boat hotels and boat restaurants etc.
From 12 boats in 1970, the tourist fleet counts for 450 boats today and employs 500 people on a permanent basis. The economic impact of this activity is important, augmenting by 10 to 60% the parts of the economy relating to the canal in the towns and villages through which it passes. The tourist industry here contributes €26m per year.
[edit] Infrastructure
- The locks : the canal originally had 56 locks to which 4 locks were added to make the connection with the River Garonne at Castets-en-Dorthe.
- The Montech water slope : this structure came into service in 1974, the brainchild of the engineer Jean Aubert. The slope allows a flight of five locks to be bypassed.
- The Aqueducts : seven aqueducts allow the canal to cross the River Garonne and its tributaries. Th most important is the Agen aqueduct, 600 metres long with 23 arches. Two other notable aqueducts are Cacor Aqueduct over the River Tarn and the aqueduct which crosses the River Baïse.
[edit] Notes and references
[edit] See also
