By the morning of Wednesday 23 October 1918, the British Front had reached the River Scheldt, north and south of Tournai. The front was in the western outskirts of Tournai, but the city itself wasn’t yet in British hands.
In the six days since 17 October 1918, the front had moved east by 15 miles (24 km). This probably represented the most rapid advance by British troops on the Lys sector.
River Scheldt
The River Scheldt (Escaut in French, Schelde in Dutch) rises at Gouy, near Le Cateau, in the Aisne département of France and flows north through Valenciennes (France) and Tournai (Belgium) to Ghent, where it is joined by the River Lys. Thereafter it continues north to Antwerp, whose citizens it “connects with the rest of the world”, according to a former mayor. After Antwerp it crosses the border into the Netherlands, and flows into the North Sea at Flushing (Vlissingen).
Encyclopedia Britannica