In Europe, more and more "sponge cities" are being created to protect against floods and droughts

Climate change is leading to increasingly sharp fluctuations: during storms, cities experience too much water, while during droughts, there is a severe shortage. According to experts, rethinking traditional urban planning principles can help solve both problems.

The concept of a "sponge city" was developed in China in the early 2000s. It involves the creation of green areas, ponds, wetlands, permeable pavements, and special drainage channels. Such elements slow down the runoff of rainwater, preventing it from immediately entering sewers and rivers. Collected water can be used to replenish underground reserves or irrigate parks during dry periods.

Green spaces also help cool streets during heatwaves. Additionally, healthy soils and wetlands can, in some cases, contribute to protection against wildfires.

China began to pay more attention to these ideas after the catastrophic floods in Beijing in 2012, which killed 79 people. In 2014, the country approved national guidelines for creating "sponge cities," and the following year launched an experimental program in 16 cities, including Wuhan, Xiamen, and Chongqing. In 2016, another 14 cities joined, including Shanghai and Shenzhen. By 2030, China plans to transform 80% of its built-up urban areas into "sponge cities."

In Europe, similar projects have been implemented for several decades.

In Malmö, Sweden, the Augustenborg district, which frequently suffered from floods, was redeveloped between 1998 and 2002. Green roofs, wetlands, water retention ponds, and six kilometers of water channels were created there. During severe storms in 2007 and 2014, this district suffered significantly less from floods than other parts of the city.

In Rotterdam, the Benthemplein water square was opened in 2013. In normal weather, it is used as a basketball court and recreational area, while during heavy rains, its three basins can temporarily hold up to 1.7 million liters of water.

In Copenhagen, Tåsinge Plads square appeared in 2014, collecting water from the roofs of neighboring buildings. For this purpose, underground reservoirs and rain gardens — shallow areas with plants through which water seeps into the soil — are used.

The European Commission intends to expand such projects. The Water Resilience Strategy, adopted in 2025, envisages the development of "sponge cities" and the restoration of more wetlands. The European Union is currently working on establishing a mechanism for financial support for such initiatives.

However, urban redevelopment faces difficulties. In historical centers, protected buildings, narrow streets, and underground utilities limit opportunities for large-scale changes. According to Justin Abbott, an employee of the engineering consulting company Arup, this should not be a reason for inaction. He proposes using local solutions: removing asphalt in courtyards, planting more trees, and creating green roofs, partially or entirely covered with vegetation.

However, "sponge cities" cannot completely solve the problem of floods. During extreme precipitation, the soil becomes saturated with water, and reservoirs overflow, so there is nowhere for excess moisture to drain. The catastrophic floods in the vicinity of Valencia, Spain, in 2024 showed the consequences that extreme rainfall can lead to when urban protection systems cannot cope with the load.

Therefore, as Abbott emphasizes, alongside nature-based solutions, cities still need traditional drainage systems, large reservoirs, and special channels for diverting floodwaters. They must accept excess water when rain gardens and wetlands can no longer retain it.

The organization of water resource management also plays an important role. Responsibility for rainwater lies with municipal authorities, water supply operators, developers, and landowners. Decisions made by one of these stakeholders can affect entire areas. Therefore, when planning and designing cities, it is essential from the outset to consider how water will be collected, stored, and drained.

• 5
• 0
• 0
• 0
• 0
• 0
• 0
• 1