Karst Zones — Metropole

Generally speaking, a potentially karst ensemble is a geological ensemble in which carbonate rocks are dominant, where superficial flows are rare outside the main valleys (regional flows) and present, locally at least, karst forms (closed depressions, dry valleys) as well as significant flow sources in the vicinity of the main valleys.

For information, the Karstic Zone layer is a national mapping of these sets, however limited to so-called active karsts, i.e. where water is potentially available. It integrates several data sources:
— The main hydrogeological entities being characterised, as a whole, by a type of ‘karstic’ environment;
— Complementary entities, of a localised karst system or impluvium type, results of different localised studies (regional inventories of betoires, tracing, etc.)

In particular, it makes it possible to highlight the sectors where active karsts are at the outcrop of those, supposedly, which lie deep under other hydrogeological entities not necessarily karst.

(According to Sandre, dictionary of the hydrogeological reference SAQ V 2.2)