Groundwater Protection in Selected Countries
3. Water Supply
| 3.1 | The groundwater resource |
| 3.2 | Supply statistics |
| 3.3 | Water supply structure |
| 3.4 | Water treatment |
| 3.5 | Drinking water criteria |
| 3.6 | Costs |
The groundwater resource in Austria stems from precipitation in Austria and from inflow of groundwater from other countries. Approximately 98,000 mill. m3 water stem from precipitation (1,170 mm) and 29,000 mill. m3 water stem from inflow from abroad. With an estimated evaporation of 43,000 mill. m3, a total of about 84,000 mill. m3 renewable water has been calculated (Draft RSEA, 1998).
From these resources, a total of 2,600 mill. m3 or only 3 % is used for water supply.
Major aquifer types
The most important aquifers used in Austria for water supply are:
 | aquifers in quaternary sediments consisting of sandy gravels and located in the major basins along the big rivers, |
| karst aquifers and spring waters within carbonate rocks of the Northern and the Southern Alps |
In mountain regions, there is often a lack of cover layers and the cover layers of the quaternary aquifers are usually very shallow. These aquifers are generally presumed to be very vulnerable. The age of spring waters in the karst aquifers of the Alps is very young in general (less than 1 year). In general, the age of the water in quaternary sediments is also presumed to be young.
Minor aquifer types
In addition to the major aquifers above, the following aquifers are found in Austria and have regional importance:
| aquifers in tertiary sediments, consisting of sand |
| aquifers in diverse sedimentary bodies as the quaternary deposits including the moraines of the Pleistocene alpine glaciers, that extended far into the foreland |
| aquifers in fractured rocks of the Bohemian massif and the Central Alps (granite and gneiss) |
More than 99 % of the drinking water supply in Austria is based upon groundwater, including spring water and bank infiltration. Less than 1 % is based on surface water (Draft RSEA, 1998).
In 1993, the total water consumption in Austria was estimated to be 2,6 billion m³. The following water consumption rates were calculated (Draft RSEA, 1998):
|
38 % - groundwater 27 % - surface water 37 % - groundwater 11 %. |
The total of the public water supply with drinking water (including domestic use, commerce and small enterprises) was 0,7 billion m³. Household consumption is about 145 l pr. person pr. 24 hours (Draft RSEA, 1998) and is stagnant to slightly decreasing through the last decade.
3.3 Water supply structureThe water supply structure in Austria exhibits features of centralisation as well as features of decentralisation. The total number of waterworks is estimated to be about 3,000. These waterworks supply 86 % of the Austrian population. In 1995, 188 large suppliers where within the Austrian Association of waterworks and provided drinking water for 65 % of the population (ÖVGW, 1995). The largest utility supplies Vienna (> 1,7 million people or > 20 % of Austrian population). More than 95% of the drinking water for Vienna is produced from to spring waters in the Alps. In contrast, 14 % of the households obtain their drinking water from private wells.
There is no specific policy for centralisation or decentralisation. There is, however, a centralisation tendency. The percentage of the households supplied by the common utilities has increased slightly throughout the last decades, as in many regions waterworks merged in clusters in order to provide drinking water at high quality, which is permanently controlled. Although the suppliers merged, very few utilities have been closed. On the other hand, tendencies for centralisation is limited naturally in many regions in Austria (e.g. little valleys in the Alps with a very low population density).
3.4 Water treatmentThe great majority of water supplies in Austria (especially those providing spring waters for drinking water) can use their raw water without treatment or by using simple treatment methods like filtration or aeration. At a number of supplies, disinfection is necessary. In general, there is no use of any advanced treatment methods like stripping and adsorption.
3.5 Drinking water criteriaTwo types of criteria are used in Austria. The actual criteria for drinking water are given by an Ordinance on the Quality of Drinking Water (TWV, 1998) while the Groundwater Threshold Value Ordinance (GSWV, 1991) provides threshold values to assess environmental challenges from diffuse sources of pollution (see 4.1.3) In general, the intervention values for groundwater at contaminated sites are set equal to the drinking water standards and the screening values are set equal to the threshold values for groundwater both of these criteria are given in Appendix 1.
Firstly, guidelines for the quality of raw water used for production of drinking water are given for a large number of parameters (WGEV, 1991). Secondly, drinking water criteria are given (GSWV, 1998). Both of these criteria are given in Appendix 1.
3.6 CostsThe average price charged per m³ to the consumer in 1995 was ATS 12,21. There is no special water tax. The usual range of the price was from ATS 6,50 up to ATS 18,-, with a minimum at ATS 3,- and maximum at ATS 30.
There is no number for the specific energy consumption for the production of drinking water in Austria, as there are great differences between waterworks producing out of spring waters in the mountains which need hardly any energy and waterworks producing out of sediment aquifers.