(FIGâ€‰1)â€‰THE HEAVY FISSURING AND THE PRESENCE OF KARST CAVITIES IN THE CALESTIENNE LIMESTONE CREATE CONSIDERABLE CAPACITY FOR GROUNDWATER STORAGE, MAKING THIS THE MAIN GROUNDWATER AQUIFER IN THE GEOPARK.In the Ardenne, conglomerates and sandstone may also, when sufficiently altered, but on a more local basis, constitute usable reserves of water. The Famenne, with its clay subsoil, has very limited aquifer potential.
FIGâ€‰2 While groundwater may sometimes be visible in caves, the vast majority of the water remains stored within the many rock fractures.
FIGâ€‰3 The geomorphological context is particularly well suited to groundwater abstraction. At a number of locations, the boundary between the lime aquifers upstream and the impermeable shales downstream lies halfway up the slope between the Famenne depression and the protrusion of the Calestienne.
FIGâ€‰4 The springs that emerge where the two lithologies come into contact can be captured and fed, by gravity alone, directly to the centre of the villages further down the slope.
FIGâ€‰5 As well as supplying around 80% of domestic water, the groundwater is used for many other applications and in particular, within the Geopark, in the production of famous local beers such as those brewed by the Abbey of Rochefort or the Brasserie de la Lesse.