European Watershed

The main European watershed is the drainage divide which separates the basins of the rivers that empty into the Atlantic Ocean, the North Sea and the Baltic Sea from those that feed the Mediterranean Sea, the Adriatic Sea and the Black Sea. It stretches from the tip of the Iberian Peninsula at Gibraltar in the southwest to the endorheic basin of the Caspian Sea in Russia in the northeast.

The Watershed runs northwards through Spain in the Iberian Peninsula towards the Bay of Biscay along the basins of Guadalquivir, Guadiana, Tagus and Douro in the west to the sources of the Ebro in Cantabria. It then follows the main ridge of the Pyrenees eastwards up to Andorra, where it again turns to the north through France along the catchment areas of Garonne (with the summit of the Canal du Midi at Seuil de Naurouze), Loire and Seine in the west and that of the Rhone in the east, marked by the Cévennes mountain range between the sources of the Allier and Ardèche tributaries.