Budapest prepares a ‘Sponge City’ concept as summer floods intensify

City authorities claim that the climate crisis is already a factor in planning, with long droughts, interrupted by heavy rainfalls, becoming commonplace

Last week, Budapest was battered by a wave of heavy rain that caused a flash flood in the city. With the effects of climate change becoming more pronounced, the Hungarian capital is experiencing extreme weather shifts more frequently.

According to a statement by city authorities, the climate crisis manifests itself in the Budapest region with long periods of droughts, which are only cut by flash floods and heavy rainfalls. This, they say, is quite similar to the situation in Vienna, which has inspired officials to copy much from the Austrian capital’s sponge city model.

Recently, the city sent a team of experts on a fact-finding mission to Vienna, where they visited the city’s climate adaptability infrastructure projects. Now, Budapest is preparing its own answer to the changing climate.

Learning from Vienna

In Budapest, this project is called ‘LIFE - Urban Rain’ (LIFE – Városi Eső) and it aims to change the way the city handles rain. The standard idea for many drainage systems involves moving water away from the urban area as quickly as possible through a system of drains and sewers and feeding it to rivers.

The sponge city concept, however, aims to reframe that into retaining as much water as possible within the city limits. This can be done through systems of dykes, park ponds, wetlands, green, unsealed spaces and underground reservoirs.

A plan of Seestadt Aspern in Vienna, where all regions drain into a central lake,
Source: City of Budapest 

This is why, at the end of May, the Budapest government sent a team of experts to Vienna, so that they can learn from their neighbour’s experience. One of their key findings is the fact that many of Vienna’s sponge city concepts have been implemented in the new district they are constructing, Seestadt Aspern, but there are still a number of measures that the Hungarian team can implement without having to rebuild Budapest from the ground up.

The partially finished Seestadt Aspern almost looks dreamy, Source: City of Budapest 

Budapest’s pilot rain retention concept

The key features of Budapest’s sponge city concept include installing rain reservoirs in the Seventh and Twelfth districts. The reservoirs will be set up in public buildings, while the retained water would be used for irrigation, cleaning roads and even for toilet flushing.

On the other hand, in the 18^th district, authorities are constructing a gravel-turf parking lot, which will unseal the soil, increase biodiversity and help with rainwater retention.