Locks: Canal de la Somme

The navigable Canal de la Somme connects the English Channel at Saint-Valéry-sur-Somme to the Canal du Nord at Péronne. There are no links to other waterways along its route. The disused section links the Canal du Nord at Péronne to the Canal du Saint Quentin at Saint-Simon with no links to other waterways along its route.

All the locks from 17 Amiens down to the sea locks at the estuary have flood gates below them. The flood gates are used as part of the lock operations of this particular lock thus turning it into a double or staircase lock. The bottom gates of the lock act as the top gates of the lower lock where the flood gates act as the bottom gates.

The locks on this canal are operated by itinerant éclusiers who are employed by the département de la Somme. They drive between the locks in distinctive orange vans. Boaters have to telephone the control centre 20 minutes before they need a lock opening. Unlike other French canals that have itinerant éclusiers, those on this canal tend to only operate one or two locks each. There are many lift and swing bridges on this canal and these are operated in the same manner by calling the control centre for an éclusier.

The following information about the 156km long Canal de la Somme is taken from French-waterways.com:

The Canal de la Somme, built in 1770-1843 to provide an outlet to the sea from Saint-Quentin, is in effect the canalised river Somme throughout the greater part of its course. It is one of the most attractive waterways of northern France, passing through a marshy valley dotted with lakes, peat marshes and gravel pits, and is ideal for pleasure cruising. Commercial traffic has all but ceased.

The waterway is entered from the Somme estuary at the harbour town of Saint-Valéry-sur-Somme, and offers an alternative approach route from the English Channel to the waterways of central France. It extends 156km to a junction with the Canal de Saint-Quentin at Saint-Simon, although the last 16km between the Canal du Nord and Saint-Simon have been closed to navigation since 2006, with no short-term prospects of restoration.

The currently navigable waterway is divided into three sections. From the sea lock (PK 156) to Abbeville (PK 142) it is called the Canal maritime d’Abbeville à Saint-Valéry-sur-Somme, designed to be used by coastal ships. From Abbeville to the junction with the Canal du Nord near Péronne (PK 37) navigation is mainly in the river, with occasional lock-cuts. In this length the river is abandoned in favour of a lateral canal over the last 17km. The third section from Péronne doubles up as a section of the Canal du Nord.

History – The river Somme was for centuries considered a strategic route for navigation inland to Picardy and Paris, potentially faster and more reliable than the Seine, particularly for trade with England. The first comprehensive plan for canalisation was produced in 1729. The meandering river was not easily tamed however, and the Intendant of Picardy reporting in 1763 found the navigation to be in a ‘pitiful state’.

Complete canalisation was authorised under Louis XVI in 1785, but works were interrupted by the Revolution. The project revived by Napoleon in 1810 included a ‘ship canal’ (canal maritime) between Saint-Valéry-sur-Somme and Abbeville. The waterway was opened to navigation above Abbeville in 1827, while the ship canal was completed in 1835.

Locks were 34m by 6.25m wide, later enlarged to Freycinet dimensions. The two locks on the section incorporated in the Canal du Nord were rebuilt in 1964 to the dimensions adopted for that project, 90m by 6m. The canal was among the first to be conceded to a local authority, in this case the Somme département, in 1992, but the concession was limited to the section west of Péronne. Transfer of ownership of the entire waterway (excepting the section incorporated in the Canal du Nord) is under discussion.