Seine Commercial craft (barges and push-tows) can use the river from Marcilly-sur-Seine, to its mouth. At Paris, there are 37 bridges. The river is only above sea level from its mouth, making it slow flowing and thus easily navigable. The Seine Maritime, from the English Channel at Le Havre to Rouen, is the only portion of the Seine used by ocean-going craft. The tidal section of the Seine Maritime is followed by a canalized section ("Basse Seine") with four large multiple locks until the mouth of the Oise at Conflans-Sainte-Honorine (170 km). Smaller locks at Bougival and at Suresnes lift the
6th Airborne Division advance to the River Seine month later they were ordered to prepare to advance. Their objective was the mouth of the River Seine, away. To assist them in carrying out their mission, the division was reinforced by the 1st and 4th Special Service Brigades, the 1st Belgian Infantry Brigade and the Royal Netherlands Motorized Infantry Brigade, as well as increased artillery support. To reach the Seine, the division had to cross three rivers that had been flooded by the Germans, and had only two roads available to them. The 6th Airborne Division began their advance on 17 August, after the German Army had started to