Extreme rainfall

1000-year flood reached on the Vienna River

Floods in Vienna

(Bild: APA/AFP )

Despite the heavy storms throughout Austria, a major catastrophe around the Wien River was prevented. Nevertheless, the heavy rainfall caused a 1000-year flood.

The current flooding of the Danube also corresponds to a 50 to 70-year flood event with around 10,000 cubic meters per second. This is the result of data analyses carried out by the Vienna Waterways Department (MA 45) after the enormous water masses receded.

Six retention basins in the Auhof 
According to the MA 45, major damage in the urban area was prevented thanks to the six retention basins in the Auhof between the 13th and 14th districts with a storage capacity of 1,160,000 cubic meters.

Excess water "temporarily dammed up"
The flood basins, also known as "reservoirs", are located on a 37-hectare area between the Lainzer Tiergarten and the Westbahn railway line directly at the confluence of the Mauerbach and the Wien River. In the event of flooding, excess water is "temporarily dammed" in the basins. The last time the Wien River was at the same level as last Sunday was in 1951.

At the turn of the century, the Vienna was regulated to improve flood protection for the city of Vienna and was designed for a 1000-year flood. Normally, the river carries around 200 to 500 liters of water per second.

The river, which rises in the western Vienna Woods near Rekawinkel, flows through nine Viennese districts over a distance of around 15 kilometers and flows into the Danube Canal at Urania. The Danube flood protection with Danube Island and the New Danube as a relief channel also worked perfectly during the current flood event.

"Around 110 million euros invested"
"In the last 20 years, Danube flood protection has been further intensively expanded and the dams raised accordingly after the record floods of 2002. In 2021, the Danube flood protection east of Vienna was finally completed and around 110 million euros were invested," says City Councillor Ulli Sima (SPÖ).

The entire dam system in and around Vienna is now designed for a flow capacity of up to 14,000 cubic meters of water per second, which roughly corresponds to the largest flood ever measured in Central Europe in 1501. Normally, around 2,000 cubic meters of water per second flow through Vienna at average water levels.