The geological profile depicted within a borehole log.

The depth of a geological boundary below ground level.

Zones inside groundwater bodies or groundwater bodies potentially leading to operational problems for shallow geothermal use due to a critical chemical composition.

Outline of a distinct volume of groundwater within an aquifer or system of aquifers, which is hydraulically isolated from nearby groundwater bodies and provides enough yield with suitable temperatures for open-loop systems (groundwater heat exchangers) with and/or without thermal storage.

Outline of a distinct volume of groundwater within an aquifer or system of aquifers, which is hydraulically isolated from nearby groundwater bodies and provides enough yield with suitable temperatures for open-loop systems (groundwater heat exchangers) with thermal storage at higher temperatures.

Locations of open pit and/or underground mining

Vulnerability assessment using DRASTIC method (Aller et al., 1987)

The average thermal gradient within a given depth interval.

Site with proven contamination of the underground.

Any subsurface installations, which might lead to conflicts with drilling wells and borehole heat exchangers.