Concrete protects Vienna: retention basins vital for flood safety!

Concrete protects Vienna: retention basins vital for flood safety!

In Vienna, concrete is becoming the invisible hero in the fight against flooding. The city has relied on the reliable building material since the Vienna River was regulated in 1899. The 8.5 meter high walls of the retention basins began to be built back then. They are still in use today and have hardly required any renovation since they were completed over 120 years ago. This reports Solid construction.

The regulatory measures now also show how important these protective systems are in the face of climate change. Recent flood events, such as that in September 2024, underscored the urgency of flood protection. Within two hours, the retention basins filled with around one million cubic meters of water, which meant that the renovation of the listed basins became urgent. This renovation work began in January 2024 and was given an additional boost of urgency by the flood, as reported by OTS reported.

Renovation and expansion of the retention basins

With an investment volume of around 30 million euros, the city of Vienna is planning a comprehensive renovation and expansion of the retention basins in Auhof by the end of 2026. The existing pools are enclosed with a waterproof reinforced concrete facing shell with a volume of around 11,000 cubic meters. This ensures water impermeability, which is an essential prerequisite for protection against flooding.

However, the technical adaptations are not the only measures. As part of the expansion, the pools are to be deepened and the weirs and dividing walls are to be raised by at least 50 cm. These renovation measures are based on 2D hydraulic drainage modeling, which determines the retention volume and ensures optimal functionality.

Biotope and support

The retention basins not only play a central role in flood protection, but are also a valuable natural biotope. They provide a habitat for numerous animal species and are the largest wetland area in the west of Vienna when water is low. As part of the renovation work, attention will also be paid to promoting biodiversity: 250 cubic meters of amphibian ponds and 24 bat boxes will be built.

Concrete has proven itself as a low-maintenance building material that offers protection against moisture and pressing water for decades. The challenges of modern times, such as the risk of extreme weather events due to climate change, require innovative and sustainable solutions in which the robust building material concrete continues to play a key role. The two sources therefore underline the necessity and efficiency of these investments.

Overall, the project in Auhof demonstrates a responsible approach to the challenges of the present and future, with a good knack for flood protection.