https://www.openstreetmap.org/way/795912355 (petite Senne) 

From ? until Crossing Albert/Mons : https://monument.heritage.brussels/fr/Anderlecht/Rue_des_Goujons/10700195 indicate that the river was dry up around 1950-1960

Per memory : Broekbeek under  Rue du Collecteur that cross the way exist as culvert (circa 1890-1910) 