Riera of Sant Cugat Nature · Sant Cugat del Vallès, Vallès Occidental, Barcelona The riera de Sant Cugat is formed by the union of several streams flowing down from the Serra de Collserola, at an altitude of between 300 and 350 metres, within the municipality of Sant Cugat del Vallès, and takes its official name at the height of the Pollancreda park. With a course of about 14 km, it then crosses the municipalities of Cerdanyola del Vallès and Montcada i Reixac, where it flows into the river Ripoll shortly before the latter empties into the Besòs; its basin, of about 50 km², belongs to the Mediterranean watershed and also receives the waters of the Serra dels Galliners. No point along its course lies more than 10 km from Barcelona. Photo: Josep Renalias (CC BY-SA 3.0) What to see and do in Sant Cugat del Vallès