Groundwater bodies

Groundwater body - overview
Photo: BMLRT/UBA

What is a groundwater body and how are groundwater bodies classified in Austria?

In the course of the implementation of the Water Framework Directive No 2000/60/EC the groundwater aquifers of the whole federal territory of Austria have been pooled to groundwater bodies. A groundwater body is a delimited water volume within one or several groundwater aquifers.  This identification is based on the geological and hydro-geological maps of the Geological Federal Institution, as well as on the results of the measuring networks recording the characteristics of groundwater and the groundwater levels.

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

Due to the identification of 138 groundwater bodies the Austrian territory is seamlessly recorded and classified into the following groundwater bodies:

63 individual groundwater bodies

 Individual groundwater bodies can be described as hydrologically interconnected, three-dimensionally delimitable water volume and have, as a rule, an extent of at least 50 . About 13.5 %, which are approximately 11,307 km², of the federal territory (83,858 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.  

66 groups of groundwater bodies

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

9 profound water bodies

Profound water bodies are, according to the Water Framework Directive No 2000/60/EC, only identified if they extend over a larger area, are important for water management due to current utilizations, and if there is sufficient knowledge about them available in order to describe them.  One profound groundwater body has been identified as individual groundwater body, the others as groups of groundwater bodies.