Photo : Original téléversé par Audouy sur Wikipédia français. / Wikimedia Commons (CC BY-SA 3.0)
La fontaine de Fontestorbes
The Fontestorbes spring, at Bélesta, in the Ariège, is a Vauclusian exsurgence, one of the ten most important in France. Its catchment area covers about 85 km², with poorly defined limits as often in karst terrain. It flows continuously for most of the year, with an average flow of about 2 m³/s, but becomes intermittent at low water, mainly from July to October.
The mechanism was established in the late 1970s by CNRS researchers from Moulis. An underground reservoir fills and then empties through a conduit; when the level drops, air rushes in through another conduit and almost entirely cuts off the flow, until the reservoir fills again. A cycle lasts on average about an hour and the flow can reach 1,800 litres per second. A listed natural site since 1921, very busy in summer, it has been developed for visits since 2006.
