The Canal du Midi | Archipel de Thau

The history of the Canal du Midi

Born of an age-old dream to link the Atlantic and the Mediterranean via the interior, the Canal du Midi was built during the reign of Louis XIV, between 1667 and 1681. We owe this bold dream to Pierre-Paul Riquet, whose proposal reached the ears of the Sun King thanks to Jean-Baptiste Colbert, Louis XIV’s influential Minister of Finance.

Determined to make his mark on history and establish France as a great power, Louis XIV asked Pierre-Paul Riquet, on 14 October 1666, to undertake the construction of the Royal Canal of Languedoc (renamed the Canal du Midi after the Revolution). A 14-year construction project then began! The major challenge: figuring out how to supply the canal with water.

Thanks to his genius and his knowledge of hydraulics, he turned his attention to the streams and rivers of the Montagne Noire as far as the Naurouze weir, which would allow water to flow towards both the Mediterranean and the Atlantic. Today, this system forms the highest point of the canal.

It was to this immense project that Riquet devoted most of his life, though he did not live to see the completion of his canal, having died on 1 October 1680 in Toulouse.

From the start of work in 1667 to the inaugural voyage in 1681, the construction mobilised up to 12,000 workers and continued between 1687 and 1694. Indeed, in the months following the inauguration, defects began to appear. Vauban was sent to the site by the King to implement a major programme of works to consolidate Pierre-Paul Riquet’s masterpiece.

Did you know?

The port of Sète was inaugurated with great pomp and ceremony on 29 July 1666. To mark the occasion, a memorable jousting tournament was organised. And so this unmissable tradition of the Mediterranean city was born, and ever since, every summer Louis, the city’s patron saint, has been celebrated during grand festivities on and around the Cadre Royal. It’s been going on for 350 years and shows no sign of stopping!

The Canal du Midi in figures

The Canal du Midi begins in Toulouse. Stretching 240 km, it leads to the Mediterranean Sea via Sète, passing through Marseillan and the Pointe des Onglous, where it ends. It is at this iconic spot that the canal’s waters flow into the Thau lagoon, 240 km from its starting point, at the Port de l’Embouchure. Access to Sète, a seaport on the Mediterranean, is just a stone’s throw away, on the other side of the Thau lagoon.

The Canal du Midi crosses no fewer than four departments, including Haute-Garonne, Aude, Hérault and Tarn, as it is in the latter that its ambitious 81-km-long supply system is located.

Added to these substantial figures are:

37 km via the Jonction and Robine canals.
1.5 km via the Brienne Canal in Toulouse.
0.5 km of the section between the Hérault and the round lock at Agde.

In terms of width, it is 18 m wide at the water’s surface and 10 m wide at the bottom, with an average depth of 1.90 m.

The exceptional engineering structures along the Canal du Midi

Beyond its sheer scale and the boldness of the project, the Canal du Midi has been a UNESCO World Heritage Site since 1996, largely thanks to the many engineering structures that line its course. Among the most remarkable are:

The Saint-Ferréol dam, built between 1667 and 1672, which was then the largest artificial reservoir in the Western world.
The Cammazes tunnel, in the Montagne Noire, which carries water from the Montagne Noire channel to the Saint-Ferréol reservoir.
The Répudre canal bridge, the oldest canal bridge in the world still in operation.
The Malpas Tunnel, the world’s first navigable tunnel, on the outskirts of Béziers.
The Fonseranes lock staircase, with its nine locks in a row.
The Orb canal bridge in Béziers, the longest on the canal.
The Libron structures, an ingenious system of works that protects the canal from the Libron’s floods.
The round lock at Agde, nicknamed the canal’s ‘roundabout’.

The Thau Lagoon, where the Canal du Midi ends

Starting in Toulouse, the Canal du Midi ends its course in the Thau Lagoon. This vast lagoon, 19 km long and 5 km wide, is renowned for its rich biodiversity. At the time, however, boatmen dreaded crossing it to reach the port of Sète. In 1832, the Canal du Midi company decided to make navigation safer by introducing tugboats, thereby establishing regular services between the canal and the port of Sète.

The founding of Sète

Once the Canal du Midi had been built, a suitable site still had to be found on the Languedoc coast for the establishment of a commercial seaport. Colbert entrusted this task to the Chevalier de Clerville, the king’s architect and engineer. Toulon was initially considered, but Colbert had just turned it into a naval port; Marseille was deemed unreliable by the king’s agents; Aigues-Mortes, Montpellier and Narbonne had long been silted up. The decision was finally made to build a new port at the foot of Mont Saint-Clair.

Did you know?
Until 1927, the town’s name was spelled ‘Cette’, a spelling inherited from a very ancient local place name.

Construction of the port began in July 1666 with the building of the Saint-Louis breakwater, followed by the rock-filling of the jetty and the dredging of the beach to connect the Mediterranean Sea to the Thau Lagoon. A 650-metre jetty was then built to protect the entrance to the old port. As the original contractor was unable to meet the deadlines, Pierre-Paul Riquet took over the works in 1669 and had houses, stables and warehouses built, promoting the growth of fishing and import-export activities thanks to the canal. Maritime activity gradually attracted people from neighbouring areas. From 1807 onwards, following a harsh winter that had frozen much of the French vineyards, Sète became a major stop on the Languedoc wine route, a popularity that lasted until the phylloxera crisis in 1882.

Did you know?
In 1710, the port of Sète was attacked by the British. This episode led to the creation of the present-day Théâtre de la Mer, a former defensive fort designed by Vauban and built by Antoine de Niquet.

The Pisse-Saumes Canal in Marseillan-Plage

Since 1973, the Thau Lagoon has been connected to the Mediterranean via the port of Sète, as well as via the Pisse-Saumes Canal on the Marseillan side. Its origins date back to the Second World War: fearing an Allied landing, German forces set about digging an anti-tank trench in the Pisse-Saumes estuary with the help of local people, before abandoning the project. It was subsequently nicknamed ‘the Germans’ Canal’.

The idea of linking the lagoon to the sea nevertheless gained ground, with the aim of providing the resort of Marseillan-Plage (founded in 1947) with its own port, following a different route from that envisaged during the war. After some twenty years of planning, the government approved the resumption of works in 1971, which were completed in 1973. Small boats were then able to travel between the lagoon and the sea. Today, the Pisse-Saumes Canal provides a permanent link and ensures a constant renewal of seawater in the lagoon, enriching the environment with plankton and microorganisms, which benefits the quality of the shellfish farmed in the basin.

Did you know?
The Pisse-Saumes Canal owes its name to the mules which, with their hooves in the water, would relieve themselves whilst crossing it.

Ports worth stopping at

When you arrive at the Thau Lagoon, do take the time to stop off at our ports and discover the treasures of the Thau Archipelago.

For example:

Marseillan-Ville — More information
Marseillan-Plage — More information
Mèze — More information
Bouzigues — More information
Balaruc-les-Bains — More information
Sète — More information
Frontignan-Plage — More information

Places and stops to discover

Below is a non-exhaustive selection of ports, mooring points, places of interest and museums to visit during your stay on the Thau Lagoon.

The Canal du Midi website also lists all the towns along the route, as well as the activities, leisure options, monuments and cultural sites to discover on your journey, not to mention the accommodation and restaurants where you can stop off. To access it, simply click here.

1Shellfish farms where you can sample local specialitiesSee the shellfish farms

Renowned for its shellfish, the Thau Lagoon is home to nearly 2,500 shellfish farms, whose produce is prized for its distinctive flavour. Seafood lovers, we recommend stopping off at one of our producers for a tasting right by the water’s edge.
Did you know?
The shellfish industry is the second largest agricultural sector in the Hérault, after wine production. With its 500 farms, the Thau basin alone accounts for 90% of Mediterranean shellfish production and 10% of national production.

2Exploring the Thau Lagoon by bikeRead the article

To make sure you don’t miss out on any of the treasures of the Thau Archipelago, moor your houseboat in one of our ports and hire a bike to cycle around the lagoon. Thanks to the many cycle paths and greenways that circle it, you can explore the following from the mainland:
- Marseillan-Plage and the Lido greenway linking it to Sète.
- La Corniche, the Théâtre de la Mer and the Pointe Courte district in Sète.
- The shores of the lagoon from Balaruc-les-Bains.
- The Crique de l’Angle, near Balaruc-le-Vieux.
- The shellfish farms and oyster beds between Bouzigues and Marseillan-Ville.
- The meadows of Soupié, between Mèze and Marseillan-Ville.
- The Noilly Prat distillery, on the quays of Marseillan-Ville harbour.
- The Pointe des Onglous and the mouth of the Canal du Midi, between Marseillan-Ville and Marseillan-Plage.

3Browsing tips

When planning a trip on the Canal du Midi, we recommend that you check the navigation guidelines directly on the canal’s website before setting off. Navigation on the Thau Lagoon, meanwhile, is strictly regulated: the area is home to a rich biodiversity and shellfish farms. You will find all the relevant information on the Hérault Prefecture’s website.

4Eco-friendly river practices

Are you spending your holiday on the Canal du Midi or the Canal du Rhône in Sète? This is your chance to discover a rich heritage, but also a fragile environment that needs to be protected. Eco-friendly actions are simple and easy steps you can take from the moment you start planning your trip, whether you’re at the port or out on the water, to reduce the impact of your activities. Every action counts. Find out more on the Écogestes Méditerranée Occitanie website.

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