Viaur

The Viaur is a river in southern France, left tributary of the Aveyron river. It flows through the Aveyron, Tarn and Tarn-et-Garonne departments. 
Geography.
The Viaur river has a length of and a drainage basin with an area of .
Its discharge (volume of water which passes through a section of the river per unit of time) has been observed from 1937 to 2017 in Laguépie, a "commune" of the Tarn-et-Garonne department near the confluence with the Aveyron river. Its average yearly discharge at Laguépie is .
Average monthly discharge (m3/s) at Laguépie
Course.
The Viaur river starts on the sides of the "Puech del Pal" in the "commune" Vézins-de-Lévézou, in the Aveyron department, at an altitude of .
The Viaur passes through the departments and towns of:
The Viaur river flows through 30 "communes" and two of them have the name of the river: Sainte-Juliette-sur-Viaur and Saint-Just-sur-Viaur, both in the Aveyron department.
Finally, it flows into the Aveyron river in the "commune" of Laguépie, in the Tarn-et-Garonne department, at of altitude.
Main tributaries.
The main tributaries of the Viaur are:
Left tributaries:
Right tributaries: