Hers-Vif

The Hers-Vif, also named Grand Hers or simply Hers, is a long river in southern France, right tributary of the Ariège.
The Hers-Vif rises at an elevation of about near the Chioula Pass of the Pyrenees, approximately north of Ax-les-Thermes. It is the major tributary of the Ariège into whose right bank it flows upstream from Cintegabelle in the Haute-Garonne.
It flows some through the Pyrenees, descending to the village of Peyrat, where it reaches a piedmont plain. Its valley widens as it traverses the plain, reaching the medieval city of Mirepoix, which marks the start of its lower valley.
Several rivers flow into it:

From the Pyrenees: the ; the ; the
From the piedmont plain and hills: the Blau and the ;
From the hills of Lauragais and Razès: the and the

Departments and towns along its course are:

Ariège: Prades, Bélesta, La Bastide-sur-l'Hers, Mirepoix, Mazères
Aude: Comus, Chalabre
Haute-Garonne: Calmont

Floods

The Hers is probably known as vif because of its sometimes spectacular floods – that of 16 June 1289 having entirely destroyed Mirepoix. More recently, there have been:

23 June 1875: estimated flow rate of at Mazères;
6 February 1919: estimated flow rate of at Mazères;
19 May 1977: estimated flow rate of at Mazères;
16 January 1981: estimated flow rate of at Mazères;
11 June 2000: estimated flow rate of at Mazères;
24 January 2004: estimated flow rate of at Mazères.