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.
Caia (river) The Caia is a river in the Iberian Peninsula, a tributary to the Guadiana. It is one of the main water courses in the Portalegre District, Portugal. Portugal does not recognise the border between the Caia and Ribeira de Cuncos River deltas, since the beginning of the 1801 occupation of Olivenza by Spain. This territory, though under "de facto" Spanish occupation, remains a "de jure" part of Portugal, consequently no border is henceforth recognised in this area.