 The minimal discharge reported is .The river rises in the Le Lari massif of the province of Pistoia (Tuscany) at about above sea level, from two streams that join near Le Piastre, in the "comune" of Pistoia.Its upper course marks the border between Tuscany and Emilia-Romagna and flows in a wooded area crossed by the Bologna-Porretta-Pistoia railway line (inaugurated in 1864 and one of the most outstanding for the time as for engineering effort).