Information about the 72km long river Sèvre Niortaise

SevreNiortaise-location

The Sèvre Niortaise is navigable from Niort to its estuary in the Atlantic Ocean at Aiguillon bay (north of La Rochelle), a distance of 72km. Much of its course lies in the regional park of the Marais Poitevin, a fenland area ideal for cruising in smaller boats. The waterway may be divided into two distinct sections. The first, extending 54km from Niort to Marans, is canalised river navigation. Connection is made in this section with the canalised rivers Vieille Autise, Mignon and Jeune Autise. The second section, 18km from Marans to the sea, is maritime and part of its length is bypassed by a ship canal, the Canal maritime de Marans-au-Brault, by which coasters gain access to the small seaport of Marans. The situation is made clear by the accompanying map. For convenience, the connect­ing waterways are also described under this entry.

Canal de la Vieille Autise The Canal de la Vieille-Autise is made up essentially of the canalised river Autise and is navigable over a distance of almost 10km from the Sèvre-Niortaise near Damvix (PK 32) to the head of navigation in a small basin at the village of Courdault.

Mignon The canalised river Mignon, generally known as the Canal du Mignon, is the longest of the Sèvre tribut­aries. It is navigable for boats with limited draught from its confluence with the Sèvre-Niortaise at PK 34.3 to the small town of Mauzé-sur-le-Mignon, a distance of 17km.

Autise (Jeune) Although officially designated a river navigation, the Jeune-Autise is essentially a man-made cut, which receives part of the natural flow of the river Autise through a 4.5km feeder canal. It extends almost 9km from a junction with the through route of navigation on the Sèvre-Niortaise at Maillé (PK 37.3) to a basin in the village of Souil, the first 1.2km being in a navigable loop of the Sèvre. Regrettably, the very small dimensions of its only lock at Maillé make the navigation inaccessible to all but the smallest boats.

SevreNior-regHistory – The first plans for canalisation of the Sèvre and drainage of the marshland were drawn up by Humphrey Bradley in the mid-16th century. Napoleon I took up the project in 1808 but little progress was made before the engineer Évrard designed in 1862 the plans for all the structures and artificial cuts as built. The main purpose of the navigation was to carry to the seaports of Marans or La Rochelle the timber produced in the Marais Poitevin The ship canal from Marans to Le Brault was started in 1891 and opened at the turn of the century.


Key Waterway Dimensions

  • Max Beam: 5.20m
  • Max Height: 1.10m
  • Max Draught: 0.80m

Navigation

Traffic amounts to no more than 150 to 200 boats per year, one important limiting factor being the draught and headroom in the upper reaches, another being the hostility of the local population to powered boats. Careful navigation is called for, so as not to worsen the situation, and depending on the boat’s size and hull shape it may be advisable to cruise at below the maximum permitted speed of 10km/h, especially when passing the countless flat-bottomed river boats which ply the river. However, the greatest difficulty is likely to be weed clogging the propeller

Locks – In the first section from Niort to Marans there are 8 locks, dimensions 31.50 by 5.20m (minimum), overcoming a total difference in level of 8m.Their use is controlled during the low flow period, which unfortunately corresponds to the pleasure cruising season (June to October). The maritime section has one lock (Enfreneaux), measuring 40 by 7m, a short distance downstream of Marans. There is also a ship lock, 126 by 11m, at the seaward end of the Canal maritime de Marans au Brault. The lock on the Vieille-Autise has a length of 31.50m and a width of 5.20m. On the Mignon, there are four locks, offering minimum dimensions of 31.50 by 5.10m. They overcome a difference in level of 4.65m. On the Jeune-Autise, there is just one lock, at Maillé. It has severely restricted dimensions of 7.00 by 3.00m (designed for small river boats and timber rafts).

Draught – From Niort to lock 7 (Bazoin), the mean water depth is 1.60m, reduced to 1.40m during periods of drought. However, there are shoals downstream of locks 3 (Tiffardière) and 4 (Marais-Pin) and at La Barbée (PK 32), where the guaranteed depths are further reduced to 1.20m (mw) and 1.00m (lw). From Bazoin to Marans depths are greater: 2.50m (mw) and 2.00m (lw). On the tidal Sèvre below Enfreneaux lock, the depth ranges between 1.00m at low tide and 5.50m at high tide. The port of Marans and the ship canal offer depths of 5.35m (mw)/4.50m (lw). Depths in the various bypassed sections of the river between lock 7 (Bazoin) and Marans are 1.50m (mw)/1.00m (lw).Vieille-Autise: The normal depth of water is 1.20m, but this drops to 0.80m during the summer low water period.

Mignon: From the confluence to a short distance upstream of La Grève-sur-Mignon the normal depth of water is 1.20m, falling to 0.60m at low water. In the upper reaches no more than 0.60m may be counted upon in normal conditions, reduced locally to 0.40m at times of low water. It should be mentioned that these depths, although insufficient for large cruisers, are adequate for the local flat-bottomed river boats which ply the Sèvre-Niortaise and its tributaries. On the Jeune-Autise, from the Sèvre to the lock at Maillé, the normal depth of water is 2.20m, reduced to 1.70m during the summer low water period. Similar depths are available above the lock, but the lock itself has a very shallow sill, offering a depth of only 0.50m at normal water level, reduced to 0.20m at low water.

Headroom – Craft aiming to reach Niort should not be higher than 2.20m, which is the least headroom offered at mean water level in the section above lock 5 (Sotterie). At the highest navigable water level the headroom is reduced to 1.10m, but this would be an exceptional occurrence during the cruising season. From lock 5 to Marans the minimum headroom is 2.40m (mw)/1.70m (lw). The new bridge downstream of Brault offers ample headroom.The minimum headroom under the bridges above normal water levels is 3.05m on the Vieille-Autise, 3.30m on the Canal du Mignon and 2.40m on the Jeune-Autise.

Towpath – There is officially a rough towpath throughout, but conditions probably vary widely according to local usage and towpath access should not be counted upon.

Authority – Direction Départementale de l’Equipement des Deux-Sèvres, Hydraulique Navigation – 52 quai Maréchal Foch, 17230 Marans
Click to enlarge

Route description

Sèvre Niortaise

PK 72.0    Port du Pavé causeway l/b, moorings, estuary opens into Aiguillon bay
PK 67.9    Le Corps de Garde moorings l/b, limit of sea
PK 65.6    Lift bridge (Pont du Brault)
PK 64.9    Entrance to ship canal (Canal maritime de Marans au Brault) through Le Brault lock), l/b (Note: the canal is 5.2km long, while the tidal section of river it bypasses is 9.7km)
PK 64.8    Former moving bridge (Pont du Brault)
PK 55.6    Lock (Enfreneaux) r/b, to tidal Sèvre, bridge
PK 55.2    End of ship canal, navigation re-enters river
PK 55.0    Junction with former Canal de Marans à La Rochelle, l/b (disused)
PK 54.4    Port of Marans, end of maritime waterway, moorings for 10 visitor boats, night €5.70, water, electricity, showers, crane 3.2t, slipway, repairs
PK 54.2    Lock 8 and weir (Carreau d’Or)
PK 53.9    Marans bridge, town l/b
PK 53.2    Entrance to outlet drain, r/b (not navigable)
PK 52.2    River divides, take l/b arm
PK 50.9    Confluence of Vendée, r/b (unpowered boats only)Marans Junction Plan Sevre Niortaise
PK 50.8    Railway bridge
PK 50.7    End of Canal de Pomère
PK 50.6    L’Île d’Elle bridge, village 1200m r/b
PK 45.9    Entrance to Canal de Pomère, r/b, navigation possible in bypassed section (Contour de Pomère)
PK 45.1    Short meander cutoff, l/b (d/s of yacht club)
PK 42.7    Entrance to meander cutoff (Canal du Sablon) r/b, navigation possible in bypassed section (Contour des Combrands)
PK 42.1    Footbridge
PK 41.3    End of meander cutoff
PK 38.9    Bridge (Sablon)
PK 38.2    Entrance to meander cutoff (Fossé du Loup) l/b, junction with Canal de la Jeune Autise  via the bypassed loop (Contour de Maillé), bridge, access to village of Maillé
PK 37.3    End of meander cutoff
PK 36.4    Junction with Canal de la Rabatière, l/b (not navigable)
PK 36.2    Rabatière diversion canal, l/b (no interest for navigation)
PK 35.0    Bridge (Croix des Maries)
PK 34.3    Junction with Canal du Mignon, l/b
PK 34.0    Lock 7 and weir (Bazoin), bridge This lock has sloping sides. PK 32.5    Junction with Canal de la Vieille Autise, r/b
PK 32.0    La Barbée, r/b
PK 31.3    Les Loges, r/b
PK 30.1    Damvix bridge, moorings and slipway u/s r/b, village r/b
PK 29.2    Confluence of Vieille Sèvre, r/b
PK 28.7    Lock 6 and weir (Bourdettes), lift bridge
PK 27.5    Entrance to Arçais arm, l/b
PK 25.6    End of Arçais arm, l/b (navigation uses r/b arm)
PK 23.7    Footbridge (Cabanes de la Sèvre)
PK 21.2    Irleau bridge, village 1000m l/b
PK 19.1    Lock 5 and weir (Sotterie), bridge
PK 16.6    Junction with canal to La Garette, l/b (small boats only)

Sevre Niortaise Quay Damvix
Trip boat at the quay in Damvix © Mark C. Caprioli

PK 16.4    Footbridge
PK 16.0    Coulon-Sansais bridge, moorings and slipway d/s r/b, small boats for hire, village r/b
PK 13.6    Lock 4 and weir (Marais-Pin)
PK 10.9    Magné lift bridge, quay d/s l/b, village l/b
PK 10.1    Sevreau arm l/b (navigable by small boats 500m to Sevreau bridge)
PK 8.3    Railway bridge
PK 8.1    La Tiffardière bridge, village r/b
PK 7.6    Lock 3 and weir (Tiffardière), sloping sides
PK 6.8    Lock 2 and weir (Roussille), bridge
PK 6.0    Saint-Liguaire slipway, moorings, village l/b
PK 4.2    Bridge (boulevard Willy Brandt)
PK 2.5    Tellouze castle r/b
PK 1.5    Main road bridge (Niort bypass)
PK 0.9    Lock 1 and weir (Comporté), sloping sidesBazoin Junction Plan Sevre Niortaise
PK 0.0    Niort canal basin, head of navigation, moorings, town centre across river

Vieille-Autise PK 9.7    Footbridge (Ouillete), confluence with  Sèvre-Niortaise (PK 32)
PK 8.4    Bernegoue bridge, village 700m r/b
PK 7.5    Bridge (Pont Noir)
PK 6.8    Lock (Saint-Arnault)
PK 3.3    Saint-Sigismond bridge, village 200m l/b
PK 2.2    Bridge (Chanceau), Liez 1500 r/b
PK 0.0    Courdault basin, head of navigation, village 300m Mignon PK 17.1    Confluence with Sèvre-Niortaise (PK 34)
PK 17.0    Lock 4 (Bazoin) and weir, bridge
PK 16.4    Entrance to Dérivation de la Rabatière (not navigable) l/b
PK 14.9    Rigole de la Garette drain enters r/b
PK 12.4    Lidon r/b
PK 9.9    Lock 3 (Grève-sur-Mignon) and weir
PK 8.7    La Grève-sur-Mignon bridge, village 700m l/b
PK 8.6    Bridge (former railway)
PK 6.4    Bridge (Port des Gueux), quay l/b
PK 5.6    Lock 2 (Sazay) disused, weir, bridge, limit of navigation The rest of this former navigation is given for reference. PK 4.2    Weir
PK 4.0    Footbridge
PK 3.6    Quay (Chaban) l/b
PK 2.7    Lock 1 (Chaban) disused, weir
PK 1.0    Bridge (Moulin-Neuf)
PK 0.0    Mauzé-sur-le-Mignon basin, head of navigation, village 1000mJeune-Autise
PK 8.9    Confluence with Sèvre-Niortaise in Maillé loop (1.2km from main route)
PK 8.7    Junction with Canal de Bourneau, footbridge, access to Maillé boat harbour
PK 8.5    Bridge
PK 8.0    Maillé bridge (Saint-Nicolas), village 400m l/b
PK 7.5    Lock (Maillé), aqueduct upstream, bridge
PK 3.3    Maillezais bridge, abbey ruins, village 800m l/b
PK 1.8    Bridge
PK 1.4    Bridge
PK 1.2    Bridge
PK 1.0    Weir (Château Vert), limit of navigation
PK 0.5    Feeder enters, l/b
PK 0.1    Bridge
PK 0.0    Souil basin, small village 200m