The rain garden at the Gembloux Agro-Bio Tech campus (ULiège) is an experimental and educational facility dedicated to the sustainable management of rainwater in urban areas. It was designed to collect, slow down and infiltrate runoff water from impermeable surfaces, thereby reducing pressure on the drainage networks and the risk of flooding, whilst promoting the natural infiltration of water into the ground.

 

This system consists of three successive stepped swales, which serve to slow down and channel surface runoff from the surrounding (semi-)impermeable surfaces. These swales direct the water towards a retention basin, structured in two complementary parts:

• a permanent pond (approx. 70 m³), which ensures the continuous presence of a water source, essential for the maintenance and development of biodiversity;
• a temporary expansion zone, which allows for the storage of an additional volume of water of almost 115 m³ when required.

The rain garden thus provides temporary storage of 315 m³, helping to offset the impermeability of the upstream area by promoting water infiltration and evaporation (restoring the hydrological cycle). It is a multifunctional facility: a tool for sustainable rainwater management, a teaching aid and a true haven for biodiversity at the heart of the campus.

Fully instrumented, the garden is equipped with sensors that measure water levels and flow rates in real time, enabling scientific analysis of the system’s operation.