Tiber River

The Tiber (, ) is the third-longest river in Italy, rising in the Apennine Mountains in Emilia-Romagna and flowing mainly through Umbria and Lazio to the Tyrrhenian Sea, between Ostia and Fiumicino.
The river is well-known because the city of Rome was founded on its eastern banks.
Geography.
The Tiber river has a length of , and a drainage basin with an area of approximately , almost 5% of the territory of the country.
It is the third longest river of Italy, after the Po and the Adige rivers, and the second by drainage basin after the Po.
Course.
The Tiber starts near the town of "Balze", Verghereto "comune" in the southwestern end of the Forlì-Cesena province, in the southern side of Monte Fumaiolo. The source of the river is formed by two springs that are from each other in a forest on the mountain at an elevation of above sea level.
The Tiber flows through Emilia-Romagna about and then it gets into Tuscany where flows through Pieve Santo Stefano and Sansepolcro. Between these two localities there is a dam with a large reservoir that is named as Montedoglio Lake (). From here, the river flows through a wide plain ("Val Tiberina") and gets in the Perugia province (Umbria) and flows through the towns of Città di Castello and Umbertide.
To the south of Torgiano, it is joined by its left side by the Chiascio river and then, in the Marsciano dam, by the Nestore river by its right side. Soon another right tributary, the Paglia, joins the Tiber.
The river forms the border between the Umbria (province of Terni) and Lazio (province of Viterbo) regions. Near the city of Orte, it is joined by the left side by its main tributary, the Nera river.
It flows through the Lazio region (Viterbo, Rieti and Rome provinces) and is joined by the Aniene river, flows through the city of Rome and, finally, into the Tyrrhenian Sea between Ostia and Fiumicino.
Main tributaries.
The main tributaries are:
Discharge.
The average yearly discharge (volume of water which passes through a section of the river per unit of time) of the Tiber is at its mouth.
The mean monthly discharges (in m³) for 2011 in Rome were: