It takes its source in a moorland at over 900 metres of altitude, in the high valley of Les Convers, (see: Renan). It flows down the whole length of the valley of Saint-Imier, (Erguel), leaving it through the gorge of Taubenloch, it flows across the city of Biel/Bienne into the Lake of Bienne, at the altitude of 429 metres, upon a stretch of 45 kilometres. It leaves it through the last leg of the Thielle river, merging into the Nidau-Büren channel (Aare river), just before the regulating dam Port .
Its main tributaries are la Dou, la Raissette, le Terbez and l'Orvine.
On December 21, 1991, the river has provoked significant flooding along its course: i.e. in Sonceboz, its level had raised by a significant 1,10 meter, with 65 cubic meters of water per second.
-  La Suze (site), Canton de Berne, consulted on September 23, 2007