Canal de la Deûle

The Canal de la Deûle is one of the oldest canals in northern France, originally connecting the river Scarpe near Douai with the river Lys at Deûlémont near the Belgian border. Roughly half of its original length has been absorbed in the high-capacity Dunkerque-Escaut waterway, as shown on the map, and the remaining length through the port of Lille is often considered as a branch of the main route, hence the alternative names Liaison or Antenne Bauvin-Lys. This official name was never adopted by the local population, which refers simply to the Deûle, evoking its original state as a natural river, although it has the size and the appearance of a built canal. It is 34.8 km long with 3 locks.
Parts of the Deule were made navigable as early as the 13th century, but goods had to be portaged round a natural sill at an island, which gave its name to the regional capital Lille. It was linked with the Scarpe in the 17th century and the Lys river in the 18th.

Wikipedia