Sustainable stormwater management tool at the neighbourhood scale

As in most cities, the natural water cycle is disrupted in the Brussels-Capital Region (BCR) because of the large and still increasing soil waterproofing in private parcels and public spaces. Consequently, severe and recurrent floods occur in the whole region. Major public works, such as stormwater reservoirs and combined sewers have proven their limits to mitigate this increasing risk. The Brussels Environment agency asked to develop a tool, at the neighbourhood scale, to promote Best Management Practices (BMPs) in the public space: the QUADEAU tool. This sustainable stormwater management tool evaluates the hydrological efficiency of a public space in a renovation or new urban project. The public space projected is modelled in the tool by characterizing all areas of the project, by creating the flow networks between these surfaces and by designing the BMPs used in network in the project. Then the tool calculates the total volumes of stormwater that percolate through the soil, evaporate, accumulate in the BMPs and finally flow into the outlet. The flow into the outlet has to match the hydrological thresholds determined in function of the total imperviousness of the neighbourhood, the type of project and the local hydrogeology. QUADEAU aims to be used for the predimensioning and for the optimization of all specific characteristics of the BMPs. QUADEAU is designed to easily adapt to all type and size of project. The tool, encoded within an Excel spreadsheet, is intuitive and easy to use for most individuals without specific engineering knowledge.