Park at the Écluses du Brault, just before the largest and last canal before the Sèvre Niortaise.
(S/E) Cross the canal via the lock and take the grassy path on the right bank, called Chemin des Enfreneaux.
(1) After a little less than 5km, you will come to a branch of the Sèvre, which you will follow on its left bank (towards the north-west) to the Écluse des Enfrenaux.
(2) At this point, the Sèvre Niortaise divides into two branches to form an island. Cross the first branch on a wooden bridge above the Écluse des Enfrenaux and immediately turn right to walk along the island to its end, still on the Chemin des Enfreneaux.
(3) Here, you can see the three branches of the Sèvre Niortaise and the start of the Canal de Marans in La Rochelle. The branch to the south of the island divides into two: one joins the northern branch of the island to form a single branch, and the other crosses the town of Marans and its port. Continue over the bridge towards Marans.
(4) After the allotments on the left, the road curves around the port in a 90° turn. Continue along Quai Foch until you reach the first footbridge.
(5) Cross the metal footbridge over the Carreau d'Or lock and turn right, following the edge of the port along Quai des Fusiliers Marins. Pass in front of the harbour master's office and follow the V43 cycle path.
(6) Cross the Canal de La Rochelle. The path joins the Vélodyssée (EV1). Continue straight ahead towards the Pont du Brault: there is a sign on the right after the bridge, in front of the sailing school. Join the Marans Maritime Canal on its left bank, opposite the Sèvre branch.
(7) Follow the Vélodyssée on the opposite bank to the path taken on the way out, along the canal. After 5 km in a straight line, you will return to the starting point at the Écluses du Brault (S/E).