Locks on the Canal du Midi

The Canal du Midi was built between 1666 and 1681 by Pierre-Paul Riquet to provide an inland water route through Southern France between the Atlantic at Bordeaux and the Mediterranean at Sète via the Garonne. The first design for the locks on the canal was a rectangular shape however due to a collapse of a side-wall early in the building program (exactly which lock is not recorded), Riquet modified his plans and rebuilt both existing and new locks with an ovoid chamber. They were typically 11 m wide at the midpoint and 6 m at the gates with an overall length of 30.5 m. ==Profile==

At its western end, Toulouse, the canal is at an altitude of and climbs to at its summit level between Ocean Lock and Mediterranee Lock west of Castelnaudary before dropping down to sea level at Sète. The graph shows the profile of the Canal du Midi from Toulouse (1), through the summit of the canal at Seuil de Naurouze (2), Castelnaudary (3), then Carcassonne (4) and Trèbes (5). The channel continues to Béziers just after Fonsérannes Lock (6), and then on to Agde (7) before flowing in to the Bassin de Thau at Sète (8). At , Naurouze is the highest point of the canal with a drop of between the summit and Toulouse and between the summit and Sète. The longest pound is between Argens Lock (Aude) and the Fonsérannes Lock (Hérault) while the shortest reach is between two locks at Fresquel. ==Locks==

The following list numbers the locks from the Canal lateral a la Garonne in the west to the Bassin du Thau in the east. Staircase locks are listed as a single entity but the number of individual chambers in the flight is noted. Travelling west to east from Toulouse to Sète the locks numbered 1–18 are ascending and 19–86 are descending. Castanet lock is the first lock with an elliptical chamber, as Riquet realised it was the best fit solution due to mechanical stress from surrounding areas. ==See also==