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
Course of the Willamette River the river, the main channel flows north by Sauvie Island, which is on the left and marine terminals and industrial areas, which are on the right. About from the mouth, the Columbia Slough enters from the right. Kelley Point Park is to the right at the confluence of the Willamette and the Columbia, about from the larger river's mouth on the Pacific Ocean. The elevation at the mouth is about above sea level. The reaches of the river below Willamette Falls are influenced by tidal effects from the Columbia River. Over its entire course, the main stem of the Willamette