A green roof buffers rainwater while harvested rain is reused on site, cutting mains water demand.
picture: Bron vdberk.be
The building combines two complementary water-management systems on a single site. A planted green roof, designed as a low-maintenance landscape with drought-tolerant species, holds back rainfall in its substrate and vegetation, slowing run-off and limiting the need for active irrigation. Rainwater that is not absorbed by the roof itself is collected and stored in a dedicated buffer tank, from where it is reused inside the building for applications that do not require drinking-water quality, most notably toilet flushing and other sanitary uses.
Sustainability added value: Together, these two systems turn what would otherwise be a one-way flow of rainwater into the sewer into a useful local resource. The green roof reduces peak loads on urban drainage during heavy showers, supports biodiversity and helps cool the building in summer, while the buffered rainwater takes a meaningful share of daily consumption off the mains drinking-water network. The result is lower water bills, less pressure on city infrastructure, and a more resilient response to both heavy rainfall and dry periods.