Assertion: drainage basin's tributary | /r/CapableOf | merge into the douro
Facets:
value: along the canyons
type: LOCATION
Source sentences:
text: Tributaries here are small, merging into the Douro along the canyons; the most important are Côa, Tua, Sabor, Corgo, Tavora, Paiva, Tâmega, and Sousa.