Warth builds huge retention basins to curb flood risk

Warth in Lower Austria is building a major flood-protection project, including huge retention basins, after suffering repeated severe flood damage. The work was reported by ORF.

The Hassbach stream, a major tributary of the Pitten, burst its banks in June 2018, causing extensive damage. The municipality had also been hit by severe flooding in 1999. Mayor Michaela Walla recalled that while water could be pumped out, thick mud left dirt everywhere, damaged equipment and knocked down fences. Residents were angry with the municipality, saying it had done nothing, she said.

Construction began in 2024, after years of calculations and administrative procedures. Five large protective barriers have been built in the Laaergraben, where land has been slipping and carrying material into the Hassbach. The barriers are intended to stabilise the ravine, said Christian Amberger, a regional head of the Torrent and Avalanche Control service.

The next phase will build retention basins with a combined capacity of 400 million litres, equivalent to about 2.6 million full bathtubs. The basins will not remove floodwater, Amberger said, but will slow the flood wave so that the volume flowing downstream does not exceed the capacity of the stream.

The project is scheduled for completion in 2030 and will cost about 16 million euros, funded by the federal government, the state and the municipality. The expense is a major burden for Warth, Walla said, adding that the municipality will have to repay the loan and cannot afford other special projects in the coming years, including a new playground.

Since 2024, 35 flood-protection projects across Lower Austria have been completed at a total cost of about 140 million euros, according to the office of state finance councillor Anton Kasser.