GUADIANA RIVER
The Guadiana is a peninsular river, as it originates in Spain, crosses Portugal and flows into the Atlantic Ocean in the Gulf of Cádiz, between Vila Real de Santo António (Portugal) and Ayamonte (Spain). It is in this gulf that forms a small estuary and an area of marshes, such as the Sapal de Castro Marim and Vila Real de Santo António Natural Reserve (in Portugal) and the Marismas de Isla Cristina (in Spain). At 829 km, it is the fourth longest river in the Iberian Peninsula. The Romans called him Anas, which means “of the ducks”. With the arrival of the Moors, they added the prefix Wadi, which means “river” in Arabic. Uádi Ana quickly came to be called Ouadiana to take shape as Guadiana, due to Castilian influence in the 16th century.
After the Christian occupation of the 13th century, the Guadiana River served as the border between Portugal and Spain for the last 110 km. At the end of the 19th century, it became an important port of entry for sea fishing boats to supply the canning factories. Today the banks of the river are mostly used by recreational boats, with the river being navigable for the last 68 km, from Mértola to the mouth. In Portugal, the river crosses the regions of Alentejo and Algarve. And it is precisely in Alqueva (Alentejo) that it forms the largest reservoir in Europe with 250 km2.