Reno (river)

The Reno is a river of Emilia-Romagna, northern Italy. It is the tenth longest river in Italy (the sixth longest of those that flow directly into the sea) and the most important of the region apart from the Po.

It has a drainage basin of about 5000 km2. The annual average discharge at the mouth is about 95 m3/s; at the point where the river starts to flow into the Pianura Padana (Po River Plain), it amounts to about 25 m3/s.

The highest values registered at the mouth have approached 2300 m3/s, but the typical value when the river is in flood is around 1000 m3/s. The minimal discharge reported is 0.6 m3/s.

The river rises in the Le Lari massif of the province of Pistoia (Tuscany) at about 745 m 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 it 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 for its engineering work). The upper course is characterized by several artificial reservoirs whose dams are used for hydro-electric energy production. The power produced in the basin of the Reno basin is second, for Apennine rivers, only to that of the Nera-Velino in Umbria.

It passes west of Bologna, at Casalecchio di Reno. In its lower course the Reno receives the water of numerous streams, some of which are seasonal. The most important include the Limentra orientale, Silla, Setta, Samoggia, Idice, Sillaro, Santerno and Senio.

The Reno was a tributary of the Po until the middle of the 18th century when the course was diverted to lessen the risk of devastating floods. It now joins the Adriatic Sea near Casalborsetti, south-east of the Valli di Comacchio.

The name of the river has the same etymology as the name of the Rhine, as both derive from the same Celtic hydronym Rēnos, the Reno basin being situated within Gallia Cisalpina, in what was the territory of the Boii before the Roman conquest of 220 BC. In Italian both rivers are called Reno, and in Latin both were called Rhenus. In 43 BC the pact establishing the Second triumvirate was signed on an islet of the river near Bononia (Bologna). The river is mentioned by Dante Alighieri in Canto XVIII of his Inferno where he defines the Bolognesi as those "living between the Savena and the Reno".