Freshwater - Drivers and pressures (Austria)

Availability of water

Characteristic for the Austrian water management situation is the comparatively large abundance of water. The annual available water yield in Austria is around 84 billion cubic metres, approximately one third of which is groundwater. The mean annual precipitation is 1,170 mm; the annual precipitation varies from more than 2,500 mm in the west to around 500 mm in the east (Figure 6).

Population

Due to the topographical conditions marked by the Alps the populated areas are concentrated in the river valleys and on the hilly landscape and plains in the north and south/east of the country (Figure 7). The very limited space available for settlement, agriculture and transport routes means that these have always had to be protected from flooding and the resulting constraints are essentially also responsible for the hydromorphological deficits. It is also these areas which, because of the favourable climate and the soils, are mainly used for agriculture (Figures 7, 8).

Water consumption

The total annual water demand is 2.6 billion m³, around 3% of the total water yield. This represents the total water requirement for usage purposes as drinking water, for agricultural irrigation and process water in trade and industry without cooling water. Of this, 0.8 billion m³ is for drinking water, 1.6 billion m³ is used by trade and industry and 0.2 billion m³ for agricultural irrigation.

A Water Exploitation Index (WEI)  of around 4% can be calculated for 19972005. This WEI corresponds to the annual total water abstraction as a percentage of available longterm freshwater resources. The WEI takes into account cooling water, contrary to the previously used ratio of total water demand versus available water amount.

Austria obtains its drinking water from groundwater (wells and springs) the proportion of surface water used for drinking purposes is less than 1%.

Future trends in the availability of drinking water should be seen in a regional context, as climate change may cause regional changes in the available amount of water.

Water supply and waste water management

Public water supply is mainly provided for by local authorities and local authority associations. Around 7.44 million people, approximately 90% of the population, have central water supply; the remaining 10%, 900,000 people, are supplied by their own private wells (VGW Austrian Association for Gas and Water, 2010). Because of the settlement structure, the connection rate to municipal waste water treatment plants is well advanced. 91.7% of the population was connected in 2006; other waste water is collected and treated in accordance with the legal provisions on decentralised plants through, for example, small sewage treatment plants.

Surface water

Hydrological and morphological pressures on surface water

Most designations for the risk category in the WFD actual status analysis are caused by hydromorphological pressures. The main causes of this lie in extensive flood protection measures for the populated areas, regulation measures in the valley areas to obtain usable agricultural areas and the intensive use of hydroelectric power.

Hydroelectric power production in Austria

Altogether, Austrias 6,400 hydroelectric, thermal, wind, photovoltaic and geothermal plants have around 67,000 GWh gross production. In 2008, the total installed maximum capacity was around 20,700 MW and the proportion of hydroelectric power plants in gross electricity production was 61%. Of this, more than two thirds were produced through diverted flow power stations and around 31% by storage power stations.

While power stations over 10 MW produce 88% of the electricity from hydroelectric power, the remaining 12% is produced by numerous small plants.

As hydroelectric power, as a renewable energy source, provides a very high proportion of the electricity production in Austria, it can be assumed in the light of the overall situation in Austria and of the aims of the Renewable Energy Directive, that the amount of elctricity produced in this way can neither be replaced by other sources of renewable energy nor be offset by saving electricity. (BMLFUW, 2010)

Pressures from pollutants on surface water

Pollution by point sources

Waste water is treated in 1,570 urban wastewater plants larger than 50 PE60, with a total capacity of around 21 million population equivalents (PE60).

For the four main parameters BOD₅, COD, total nitrogen and total phosphorus in urban wastewater, the incoming and discharged loads of wastewater treatment plants are shown in Figure 9.

The removal rate is 98% for BOD₅, 94% for COD, 77% for total nitrogen and 88% for total phosphorus. Therefore the specifications of the EU Urban Waste Water Treatment Directive (91/271/EEC) are met.

The proportion of wastewater not dealt with by urban wastewater facilities is regularly removed through small and domestic wastewater treatment plants.

The treatment of industrial wastewater, discahrged into surface waters or indirectly into a wastewater treatment facility, is regulated by 67 sectorspecific emissions ordinances.

Pollution due to diffuse sources

As regards pollutants, mainly nutrients (nitrogen and phosphorus) are relevant for Austrian surface waters, not least because of the importance of these substances for possible eutrophication of the seas the Black Sea, the North Sea. Land use by griculture and forestry is a important diffuse sources.

Nitrogen is emitted into  surface waters mainly  through groundwater and phosphorus mainly through erosion. Both in the case of nitrogen and phosphorus, inputs from diffuse sources predominate. Because of the specific situation of Austria high precipitation and mountainious topography there is a high natural background concentration particularly of phosphorus.

Nitrogen inputs from diffuse sources are mainly from agriculture, but emissions from incineration processes also contribute. Nitrogen inputs from mineral and organic fertilizers are clearly decreasing, which is also reflected in a clear reduction in nitrogen surpluses on agricultural areas since the 1990s. The level of nitrogen surpluses (Figure 10) shows that, compared to other countries, the intensity of agriculture is rather small.

Since the beginning of the 1990s, due also to the overall implementation of the nitrate action programme, there has been a clear improvement in management practice in relation to water protection.

Groundwater

Three groundwater bodies in the east of Austria that are used intensively for agriculture have failed to be of good chemical status due to nitrate pollution. Mainly due to nitrogen inputs from diffuse sources. The pressure situation regarding nitrogen and the development over time is shown in the section on surface water pollution due to diffuse sources. As regards the concentrations in groundwater, the precipitation situation and the resulting renewal rate of groundwater (distribution over time and its extent) do of course play a very important role. Particularly affected are the regions in the east of Austria where there is less precipitation.

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