Groundwater overview
Photo: BML/UBA

What is a groundwater body, how and for what purpose are groundwater bodies classified in Austria?

Almost 100% of Austria’s drinking water is obtained from groundwater and spring water. About half of this quantity is provided by groundwater. It is therefore particularly important to protect this valuable water resource accordingly.

In order to be able to take the appropriate planning steps and measures, Austria’s aquifers (rock bodies with cavities that are suitable for conducting groundwater) were divided into groundwater bodies throughout the country in the course of implementing the EU Water Framework Directive. A groundwater body is a delimited volume of groundwater within one or several aquifers. This designation is based on the geological and hydro-geological maps of the Survey of Austria (Geologische Bundesanstalt), as well as on the results of the measuring networks recording the characteristics of groundwater and groundwater levels.

Vertically, a differentiation is made between near-surface groundwater bodies and deep groundwater bodies. Near-surface groundwater bodies are those groundwater bodies up to the base of the upper relevant groundwater level, and/or those shares of the groundwater, which are in the current water cycle and cannot be called deep water bodies.

The area of Austria is completely covered by the designation of 142 groundwater bodies and divided into the following groundwater bodies:

65 Individual groundwater bodies

Individual groundwater bodies can be described as hydrologically interconnected, three-dimensionally delimitable groundwater volumes and have, as a rule, an extent of at least 50 km². About 10%, which are approximately 8,565 km², of the entire federal territory (83,882.86 km²) are assigned to individual groundwater bodies.

These individual groundwater bodies are, for the most part, found in quaternary sediments, the aquifers are formed as pore groundwater aquifers.

68 Groups of groundwater bodies

The total remaining area of the federal territory is summarised to groups of groundwater bodies. The delimitation takes place according to the hydro-geologically relevant tectonic large-scale units, as well as according to the borders of the planning areas. One of the three predominant aquifer characteristics, pore, crevice or karst aquifer, is assigned to each group.

9 Deep groundwater bodies

Deep water bodies are, according to the EU Water Framework Directive, only designated, if they extend over a larger area, are important for water management due to current utilizations, and the state of knowledge is sufficient to carry out a characterisation. One deep groundwater body was designated as an individual groundwater body, the others as groups of groundwater bodies.