Austria
The Danube is a major economic, geographical and cultural force in Austria. Draining over 96% of the country’s territory, the basin is home to 7.7 million people. The Austrian territory accounts for 10% of the total area of the Danube Basin. Austria is a mountainous country with 62% comprising mountainous terrain; the remainder is hilly, with low-lying plains to the East. Alpine geological formations run in a predominantly west-east direction, with water draining north to the Danube and south to the Drava/Drau. The gradient of the Austrian Danube is circa 0.4 ‰, much steeper than in Lower Bavaria and the Hungarian Plain. Austria’s continental climate displays high precipitation rates in Alpine areas (up to 3500mm/annum), whereas <500mm/annum is recorded in the dry Northeast. Average precipitation within the Basin is 1090mm/annum in Austria, with an evapotranspiration rate of c.500 mm/annum and an outflow via the Danube and southern/eastern tributaries of 575mm/annum. Consequently Austria contributes 46.3 km³/annum (< 25%) to the direct flow of the Danube.
Natural highlights
The Wachau Valley – a UNESCO World Heritage Site and outstanding example of a fluvial and cultural landscape
bordered by mountains; the Donau-Auen National Park - a protected floodplain area with a still relatively intact
ecosystem linking Vienna and Bratislava;
The Thayatal National Park - an impressive protected area on the River Thaya/Dyje
(Austria - Czech border); and Neusiedler See (Fertő-tó in Hungary) – also a UNESCO World
Heritage Site consisting of a large, shallow lake, more than half of which is dominated by reeds.
Human uses
Austria’s major rivers and valleys are heavily utilised: more than 40% of Austria’s Danube Basin is used for agriculture, settlements and infrastructure; most of the remainder is too mountainous for such activities. With all available valley floor space developed, there has been a marked impact on rivers. Due to this and steep river gradients resulting in low water storage capacity in the inundation zones, Austria has a long history of dealing with floods and landslides. Major river systems are also utilized for hydroelectric power generation (an important power source for the country); navigation (the Danube is a major international commercial waterway); as receiving waters for effluents and drinking water supply (nearly 100% of Austria’s domestic supply stems from alluvial and karstic ground water bodies).
Pollution
With 86% of Austrians living in houses with main sewerage. The remaining 14%, located mainly in rural areas, are the focus for future wastewater management resources. Treatment of point source nutrient discharges go beyond the requirements of the EU Urban Waste Water Directive and estimates for such discharges leaving Austria via rivers to the Black Sea are 15.2 kt/a for reactive nitrogen, and 1.2 kt/a for phosphorus. The situation for diffuse discharges is less ideal, with past data for reactive nitrogen showing elevated, although declining, concentrations in groundwater. Concentrations are high where agricultural activities take place above groundwater bodies with a limited recharge rate. However, it is the low concentrations from Alpine areas that are more important in terms of their relative share. Due to the large run-off from Austria, background fluxes are also elevated in relative terms when compared with other states. Estimates of the diffuse discharge of reactive nitrogen leaving Austria to the Black Sea is 64.3 kt/a. Regarding phosphorus, the share of reactive phosphorus from deposition is small. Estimates of the diffuse discharge of phosphorus leaving Austria to the Black Sea is 4.7 kt/a.