The Besòs is a river flowing through Catalonia, Spain, formed by the confluence of the Mogent and Congost rivers. It ends in the Mediterranean. Its full watershed includes the following cities: Aiguafreda, La Garriga, Sant Fost de Campsantelles, Canovelles, Granollers, Montmeló, Mollet del Vallès, Montcada i Reixac, Santa Coloma de Gramenet, Barcelona and Sant Adrià de Besòs. Due to its Mediterranean climate, the river can have extreme discrepancies in flow depending on the weather.