Hers-Vif
The Hers-Vif ("Live Hers", as opposed to the slower flowing Hers-Mort, "Dead Hers"), also named Grand Hers or simply Hers, is a 135-kilometre (84 mi) long river in southern France, right tributary of the Ariège River.
The Hers-Vif rises at an elevation of about 1,500 metres (4,900 ft) near the Chioula Pass of the Pyrenees, approximately 6 kilometres (4 mi) north of Ax-les-Thermes. It is the major tributary of the Ariège into whose right bank it flows 2 kilometres (1.2 mi) upstream from Cintegabelle in the Haute-Garonne.
It flows some 30 kilometres (19 mi) through the Pyrenees, descending 1,100 metres (3,600 ft) 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 Lasset; the Fontaine de Fontestorbes; the Touyre
From the piedmont plain and hills: the Blau and the Douctouyre;
From the hills of Lauragais and Razès: the Ambronne and the Vixiège.