Ardèche is a tributary of the river that has a mouth at what body of water?
Ardèche (river) The Ardèche (Occitan: "Ardecha" ) is a 125 km long river in south-central France, a right-bank tributary of the River Rhône. Its source is in the Massif Central, near the village of Astet. It flows into the Rhône near Pont-Saint-Esprit, north-west of Orange. The river gives its name to the French department of Ardèche.
Orbe (river) The Orbe (French: "L'Orbe" ) is a river of the Rhine basin. It starts in France and flows to Switzerland to finally flow into the river Aare. On the final leg of its course, it takes the name La Thièle or La Thielle. Not to be mistaken with the Orbe, which is a tributary of the Arrats.