HCOV_0230, Event area pleistocene and Pliocene Aquifer system

Flanders is made up of a variety of aquifers (sand, gravel, chalk, solid rock,...) and regionally occurring non-aquifers (e.g. clay). The sequence of these aquifers and aquitards has its own coding in Flanders: the Hydrogeological Coding of the Underground of Flanders (HCOV coding). The HCOV coding is made up of hydrogeological main, sub- and basic units. The main unit groups a sequence of geological layers that have broadly the same hydrogeological properties and thus form a whole. The main hydrogeological unit Kempens Aquifer system is formed by all tertiary and quartary deposits above the Boomer clay layer. Geographically, these layers are mainly found in the Kempen basin. This is the zone northeast of the dayzoming of the Formation of Boom. This hydrogeological zone consists mainly of a sequence of various tertiary and quartary sands, interspersed with or not important local clay layers. The sub-unit “HCOV_0230 Pleistocene and Pliocene Aquifer” forms the upper phreatic aquifer in large parts of the Kempen. It is formed by the Tertiary and early-Quartaire sands belonging to the Formats of Brasschaat, Merksplas, Mol, Powderlee, Kasterlee and Lillo and is separated from the rest of the Kempens Aquifer system by the rather thin, sometimes very local Pliocene clay layer.