Artesian well

The artesian well, discovered in the 12^th century in Artois, is a well from which water springs spontaneously.

Principle of the artesian well

This phenomenon is due to the pressurising of an aquifer when the slope of the impermeable geological layer above it forces it under its piezometric line (line of equal pressure in subterranean water). If this layer is bored, thewater gushes up the bore following the principle of communicating vessels.

Because these deep subterranean waters can be hot, artesian wells are also used in geothermalheating systems.