HCOV_0240, Pliocene Clay Layer Prevention Area

Flanders is made up of an alternation 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 Subsurface of Flanders (HCOV-coding). The HCOV coding is made up of hydrogeological main, sub and base units. The main unit groups a sequence of geological layers that have broadly the same hydrogeological properties and thus form a whole. The hydrogeological main unit Kempen's Aquifer System is formed by all Tertiary and Quaternary deposits above the Boom clay layer. Geographically, these layers are mainly found in the Kempen basin. This is the zone northeast of the day zoom of the Formation of Boom. This hydrogeological zone consists mainly of a succession of various Tertiary and Quaternary sands, alternating with whether or not important local clay layers. The sub-unit "HCOV_0240 Pliocene clayey layer" is formed by the clayey parts of the Formations of Lillo and Kattendijk and the transition between the Formations of Kasterlee and Diest. This is the geographically heterogeneous semi-closing layer at the top of the Diest Formation.