Information about the 60km long Canal du Blavet

Canal de Blavet France map

The canalised river Blavet is one of the links in the Brittany canal system. It connects with the Canal de Nantes à Brest at Pontivy (PK 206) and runs to Hennebont, a distance of 60km. From the last lock at Polvern, 2km short of Hennebont, the river is tidal and considered as a maritime waterway, giving access to the seaport of Lorient and the Atlantic Ocean (a further 14km beyond Hennebont). Major repairs were required to locks and weirs on this canalised river following major floods in 1996 and 2001. A comprehensive programme of rehabilitation works was conducted from 2002 to 2005, and the canalised river is now again fully operational. The navigation is operated and maintained by the département Morbihan, under concession from the Brittany Regional Council and with financial support.Canal de Blavet location map

History – The canalisation works were carried out by order of Napoleon in 1802 to provide access to the strategic military town of Pontivy. Like the entire Brittany canal network, its raison d’être was military defence in case of a naval blockade of the coast by the ‘perfidious Albion’. Works began in 1804 and were completed in 1825. The waterway has little recreational traffic because of the ‘barrier’ of the watershed section of the Nantes-Brest canal east from Pontivy, with its countless locks, and the real barrier of Guerlédan Dam to the west.

Key Waterway Dimensions

  • Max Beam: 4.70m
  • Max Height: 2.40m
  • Max Draught: 1.40m

Local Waterway Links


Locks  There are 28 locks, with minimum dimensions of 26.30 by 4.70m.

Draught  The original maximum authorised draught of 1.40m has been restored thanks to a substantial programme of dredging works on the lock approaches.

Headroom  The least headroom under the fixed bridges is 2.40m above normal water level. The two bridges on the tidal river at Hennebont need to be negotiated at half tide, since headroom is only 50cm at a high tide of coefficient 100, while there is hardly any depth at low tide. On either side of these bridges pontoon moorings are available, where boats can wait for the right conditions. It is preferable to proceed against the current, which is strong at half tide.

Towpath  The towpath is practicable throughout most of the length of the canalised river.

Authority  Région Bretagne – Service des Voies Navigables
Subdivision Blavet-Canal de Nantes à Brest
–    1 avenue du Commandant Ameil, 56140 Malestroit

Click to enlarge

Canal de Blavet waterway strip

Route description

PK 0.0     Pontivy basin (Bassin du Champ de Foire), junction with Canal de Nantes à Brest (PK 205.9), moorings, town centre 300m
PK 0.1     Lock 1 (Récollets), bridge, navigation enters river Blavet, quay l/b
PK 0.3     Bridge (Pont de l’Hôpital), quay d/s l/b, town centre 100m
PK 0.7     Bridge (Pont de la Caserne)
PK 1.4     Bridge (Pont Neuf)
PK 1.6     Railway bridge, quay l/b
PK 2.4     Lock 2 (Lestitut)
PK 2.7     Bridge
PK 3.2     Bridge, private quay d/s l/b
PK 4.3     Lock 3 (Signan or Saint-Michel)
PK 4.5     Bridge (Rhin-Danube)
PK 7.2     Lock 4 (Roch)
PK 9.6     Loch 5 (Divit)
PK 11.8     Lock 6 (Rimaison)
PK 11.9     BridgePontivy Canal du Blavet junction plan
PK 13.9     Lock 7 (Kerbecher)
PK 15.8     Lock 8 (Guern)
PK 16.5     Railway bridge
PK 17.3     Railway bridge
PK 17.5     Lock 9 (Saint-Nicolas-des-Eaux)
PK 17.8     Saint-Nicolas-des-Eaux bridge, quay u/s l/b, small village
PK 19.6     Lock 10 (Couarde)
PK 20.2     Railway bridge
PK 21.1     Lock 11 (Camblen)
PK 23.0     Lock 12 (Moulin-Neuf)
PK 25.0     Lock 13 (Boterneau), quay l/b
PK 25.2     Saint-Rivalain bridge, village 1500m r/b
PK 26.6     Lock 14 (Tréblavet)
PK 28.6     Lock 15 (Talhouët)
PK 30.5     Saint-Adrien bridge, small village 300m l/b
PK 30.6     Railway bridge

Mooring Pontivy Canal du Blavet
Pontoon mooring and quay on the Blavet at Pontivy © Kal8

PK 30.9     Lock 16 (Saint-Adrien), quay r/b
PK 34.2     Lock 17 (Trémorin)
PK 34.4     Railway bridge
PK 36.4     Lock 18 (Sainte-Barbe)
PK 37.0     Pont-Augan bridge, quay d/s l/b, village r/b
PK 39.4     Lock 19 (Minazen)
PK 44.6     Lock 20 (Maneruen)
PK 46.5     Bridge (Pont Neuf), quay d/s r/b
PK 47.2     Lock 21 (Rudet)
PK 49.3     Lock 22 (Trébihan)
PK 50.9     Lock 23 (Kerousse)
PK 51.2     Overhead power lines
PK 52.3     Lock 24 (Quellenec), private quay u/s l/b
PK 54.3     Lock 25 (Lochrist) in l/b arm
PK 54.6     Lochrist bridge, quays d/s, village r/b, Langroix l/b
PK 55.0     Railway bridge (disused)
PK 56.0     Lock 26 (Grand Barrage)
PK 56.3     Lock 27 (Gorets)
PK 57.3     Lock 28 (Polvern), private quay u/s r/b
PK 59.5     Disused railway bridge (dismantled)
PK 59.8     Hennebont bridge, junction with Blavet maritime, moorings d/s r/b, village l/b

The Blavet maritime, a tidal estuary covered by nautical charts and guides, gives access to Lorient, 11km, and to the Atlantic, a further 3.5km.