For sustainable stormwater management, Forest (Brussels) applies the concept of "sponge city"

With its rugged terrain, the municipality of Forest has long suffered from flooding. The classic responses – maintenance of sewers and creation of storm water basins – have shown their limits. Today, Forest is turning to innovative, sustainable and reproducible solutions that combine flood prevention, urban comfort and rediscovered biodiversity.

Each redevelopment of public space thus becomes an opportunity to integrate sustainable and integrated rainwater management. The objective is simple: to restore the natural water cycle by letting rainfall infiltrate the soil, evaporate thanks to vegetation and recharge the water table, rather than saturating the sewers.

An exemplary pilot project

The redevelopment of a district in the south of the municipality (Bia Bouquet square and avenues du Bempt, Kersbeek and de la Verrerie) illustrates this approach. This project was crowned at the Green Solutions Awards 2023 and distinguished at COP28 for its exemplarity.

Some integrated devices:

•  Permeable roads and parking lots that collect and store water in stone foundations.

• Rain gardens and drainage trenches that filter, retain and purify water by phytoremediation.

• A separate network dedicated to rainwater, which will eventually make it possible to recharge the ponds of the Bempt Park via the old bed of the Zandbeek stream.

On the surface, the small square of the district has been transformed into a real living space : tree plantings, benches, petanque courts, widened sidewalks, peaceful meeting areas. In summer, the vegetation brings freshness and well-being thanks to evapotranspiration.

Concrete benefits

These developments offer multiple advantages, easily reproducible elsewhere:

• Reduction of the risk of flooding by relieving the sewer network and the treatment plant.

• Limitation of the discharge of polluted water into waterways (such as the Senne).

• Cooling of urban air and mitigation of heat islands.

• Improvement of the landscape and ecological quality of public space.

A structuring commitment for the future

While Forest has historically lost most of its streams over the course of urbanisation, the municipality is now committed to reintroducing water and nature into the heart of its neighbourhoods. Integrated stormwater management is now a cross-cutting priority, integrated into:

• the renovation of public spaces,

• municipal construction projects,

• the management of green spaces.

Several developments have already been completed and new projects are underway, with the ambition to transform each urban redevelopment into  a climate resilience laboratory.

An invitation to European cooperation

Forest's approach can be replicated in other European municipalities facing the same climate challenges: floods, heat waves, loss of biodiversity. We want to:

• Sharing our expertise with European partners,

• Develop joint projects to adapt our cities to climate change,

• Multiply green solutions that restore water to its place in the natural cycle.

By reinventing the city with and for water, Forest demonstrates that the ecological transition is also an opportunity to improve the quality of life of residents.