Groundwater Vulnerability Card: the aquifer layer

The map of the vulnerability of the groundwater of the Flemish Region can be defined as a map of the level of risk of contamination of groundwater in the upper water layer by substances that penetrate from the soil into the ground, only taking into account static parameters. This map can later serve as a basis for a more detailed map, which can also include dynamic and hydrochemical factors. Where, however, the upper aquifer is naturally silted (>>The aquifer Determining the classification of the aquifers are the nature of the rock, the permeability and the way in which a contamination behaves. There are four classes: * chalk, limestone, marl, sandstone; * gravel; * sand; * clay-containing sand, clay-containing sand.