Locks on the Canal du Midi

File:Lock sign at Pechlaurier Lock.JPG

Lock sign on the Canal du Midi

There are 91 working locks on the Canal du Midi along its course from the Bassin du Thau on the Mediterranean coast to the junction with the Canal lateral a la Garonne in Toulouse. There are a further 13 locks on the La Nouvelle branch which runs through Narbonne to the Mediterranean at Port-la-Nouvelle. The locks are all under the management of the French navigation authority, Voies navigables de France.

Construction

File:Lock keepers house - Pechlaurier Lock on the Canal du Midi.JPG

Typical lock keeper's house 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 11m wide at the midpoint and 6m at the gates with an overall length of 30.5m. Riquet also restricted the maximum rise to 2.9m so whereas previously he would have built one deep lock he instead used intermediate gates creating double, triple and sometimes quadruple chambers. During the Canal du Midi modernisation program of the 1970s several of these multiple chambers were converted into single "deep" locks with concrete side walls.

The lock gates were originally made of oak in the traditional mitre pattern with balance beams and each gate had a single large wooden sluice drawn up by a vertical screw. The introduction of electric and hydraulic systems for both the lifting of the sluices and the opening of the gates has seen the removal of the balance beams and modern gates are of metal construction.

At each lock there is a double-fronted two-storey lock keeper's house upon which is fixed either a cast iron or a masonry sign showing the name of the lock and the name and distance to the adjacent locks in each direction. The locks are still operated by lock keepers and passage is only possible when they are in attendance however on La Nouvelle branch operation by boaters is allowed. The locks are open every day except 1 January, 11 November and 25 December, from 08:00 until 17:30 out of season and 08:00 until 19:00 in the summer peak; all locks are closed 12:30 – 13:30 for lunch.

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.

File:Profil canal du midi.png

Profile of the Canal du Midi (distances in metres from Toulouse and height in metres above sea-level)

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

Template:GeoGroupTemplate 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.^[B] 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.

Locks in the Canal du Midi

Lock number[A]	Lock name	Coordinates (links to maps and satellite images)	Number of chambers	Distance from Toulouse (km)	Image	Altitude (metres)
1	Béarnais Lock		1	1.1	File:CanalDuMidiEcluseDuBearnaisToulouseRueDuBearn.JPG	135m
2	Minimes Lock		1	2	File:Canal-midi-ecluse2.JPG	139m
3	Bayard Lock		1	3.6		145m
4	Castanet Lock		1	15.7	File:Ecluse de Castanet.jpg	148m
5	Vic Lock		1	17.4	File:Vic Lock on the Canal du Midi.jpg	151m
6	Montgiscard Lock		1	24.9	File:Montgiscard (Haute-Garonne, Fr) Canal du Midi, écluse avec bateau (2).JPG	155m
7	Aygues-Vives Lock		1	28.1	File:Écluse d'Ayguesvives sas.JPG	159m
8 - 9	Sanglier Lock		2	29.6	File:Ecluse double du sanglier - partie amont.jpg	163m
10	Négra Lock		1	33.3	File:France Canal du Midi écluse de Négra.jpg	166m
11 - 12	Laval Lock		2	37.5	File:Laval Lock - Canal du Midi.jpg	170m
13	Gardouch Lock		1	38.9	File:Le port de Gardouch sur le canal du midi.jpg	173m
14	Renneville Lock		1	43.0		176m
15 - 16	Encassan Lock		2	45.9	File:Encassan Lock - Canal du Midi.jpg	185m
17	Emborrel Lock		1	47.5	File:Emborrel Lock on the Canal du Midi.jpg	189m
18	Océan Lock		1	51.6	File:France Canal du Midi écluse de l'océan.jpg	193m
51.5	Summit (Seuil de Naurouze)			52		193m
19	Méditerranée Lock		1	56.6	File:Lock house at Mediterranee Lock on the Canal du Midi.jpg	193m
20-21	Roc Lock		2	57.5		189m
22 -24	Laurens Lock		3	58.7		180m
25	Domergue Lock		1	59.7		175m
26	Laplanque Lock		1	60.9		173m
27 - 30	Saint-Roch Lock		4	65.4	File:Canal du Midi Schleussen bei Castelnaudary.jpg	170m
31 - 32	Gay Lock		2	67.1		159m
33 - 35	Vivier Lock		3	68.7	File:Écluse du Vivier.jpeg	154m
36	Guilhermin Lock		1	69.1	File:Écluse de Guillermin.jpeg	147m
37	Saint-Sernin Lock		1	69.7	File:Écluse de Saint-Sernin.jpeg	145m
38	Guerre Lock		1	70.6	File:Écluse de la Guerre.jpeg	141m
39	Peyruque Lock		1	71.7	File:Écluse de la Peyruque.jpeg	139m
40	Criminelle Lock		1	72.2	File:Écluse de la Criminelle.jpeg	137m
41	Tréboul Lock		1	73.6	File:Écluse de Tréboul.jpeg	134m
42	Villepinte Lock		1	77.4	File:Écluse de Villepinte.jpeg	130m
43	Sauzens Lock		1	79	File:Écluse de Sauzens.jpeg	127m
44	Bram Lock		1	80.3	File:Écluse de Bram.jpeg	126m
45	Béteille Lock		1	85.9	File:Écluse de Béteille.jpg	123m
46	Villeséquelande Lock		1	93.4	File:Écluse de Villeséque.jpg	122m
47 - 48	Lalande Lock		2	98.2	File:Écluse de Lalande.jpg	116m
49	Herminis Lock		1	98.5	File:Écluse d'Herminis.jpg	114m
50	Ladouce Lock		1	99.9	File:Ecluse de Ladouce.jpg	109m
51	Carcassonne Lock		1	105.5	File:Port de Carcassonne.jpg	106m
52	Saint-Jean Lock		1	108.0	File:Ecluse de Saint Jean.jpg	102m
53 - 54	Fresquel Double Lock		2	108.8	File:Écluse double de Fresquel.jpg	97m
55	Fresquel Single Lock		1	109.0	File:Écluse simple de Fresquel.jpg	92m
56	Evêque Lock		1	112.6	File:Écluse de l'Évêque - Canal du Midi.JPG	91m
57	Villedubert Lock		1	113.4	File:Écluse de Villedubert - Canal du Midi - 03.JPG	86m
58 - 60	Trèbes Lock		3	118	File:Trebes Lock on the Canal du Midi.jpg	84m
61	Marseillette Lock		1	127.2	File:Marseillette Lock.jpg	79m
62 - 64	Fonfile Lock		3	130.4	File:Canal du Midi – Écluse triple de Fontfile à Blomac005.JPG	76m
65 - 66	Saint-Martin Lock		2	131.6	File:St Martin lock - Canal du Midi (Nancy).JPG	67m
67 - 68	Aiguille Lock		2	133.4	File:Péniche Le Tourville écluse de l Aiguille Canal-du-Midi.JPG	59m
69 - 70	Puichéric Lock		2	136.4	File:Puichéric Lock - Canal du Midi (Nancy).JPG	57m
71	Jouarres Lock		1	142.7	File:Jouarres Lock - Canal du Midi (Nancy).JPG	49m
72	Homps Lock		1	146.4	File:Homps Lock on the Canal du Midi.JPG	46m
73 - 74	Ognon Lock		2	147.1	File:Ognon Lock on the Canal du Midi.JPG	41m
75 - 76	Pechlaurier Lock		2	149.8	File:Pechlaurier Lock on the Canal du Midi.JPG	38m
77	Argens Lock		1	152.3	File:Argens Lock on the Canal du Midi.JPG	32m
78[B]	Fonserannes Lock		6 (+2 unused)	206.6	File:Béziers Fonséranes P1100874.jpg	32m
79	Orb Lock		1	208.0	File:Orb Lock on the Canal du Midi (Nancy).JPG	12m
80	Béziers Lock		1	208.4	File:Beziers Lock.JPG
81	Ariège Lock		1	212.5	File:Ariege Lock.JPG	9m
82	Villeneuve Lock		1	213.8	File:Villeneuve lock.JPG	6m
83	Portiragnes Lock		1	218.3	File:Portiragnes Lock 1.JPG	5m
84	Agde Round Lock[C]		1	231.4	File:Agde bassin rond 3 portes.JPG	4m
85	Prades Lock		1	232.9	File:Prades lock 2.JPG	3m
86	Bagnas Lock		1	235.3	File:Bagnas lock 2.JPG	2m

See also

• Aqueducts on the Canal du Midi
• Water features on the Canal du Midi

Notes

^A Lock numbers are as given in the appendix of the 1994 edition From Sea to Sea by L.T.C. Rolt

^B The flight at Fonserannes was "replaced" by a water slope in 1984 hence the single "lock number". However, the slope has never worked and the 6 flight staircase remains the only way to pass through meaning that there are 91 locks but only 86 numbers.

^C Chamber has three sets of gates, the third being the junction with the branch descente dans l'Hérault