Rain garden for the greening of a public car park

Brief intro to the WaterMan pilot measure

In Braniewo, Poland, a “rain garden” was created in the car park of the local swimming pool. A part of the area has been unsealed and redesigned by planting vegetation and by creating a catch basin so that stormwater running off the asphalt and the roof of the indoor swimming pool is retained on site to infiltrate gradually into the soil – instead of increasing pressure on the sewage system.

The rain garden is able to store at least 30 millimetres of precipitation per square metre (following standards used in Gdańsk). This will provide sufficient water to the plants in the car park, naturally promote greening and reduce the need for additional irrigation with drinking water. The rain garden also delivers wider ecosystem and urban-development benefits: it reduces the effect of urban heat islands, increases biodiversity and treats of stormwater through sedimentation, filtration, sorption, and the uptake of biogenic compounds by the plants. Aesthetic and educational value comes with is, too.

• Type of pilot measure: Real-world implementation
• Location: Braniewo (Poland)
• Water source: Stormwater
• Type of treatment: Natural self-purification processes (sedimentation, filtration, sorption, biodegradation) enhanced by eco-engineering design
• Target water quality: Natural stormwater quality
• Utilisation: Irrigation of plants in the car park
• Return to natural cycle: Increased infiltration and evapotranspiration
• Responsible: Braniewo Municipality / Gdańsk University of Technology
• Operational & open for visitors: Since Sept 2025