Extreme weather events such as heavy rainfall or drought, which accompany climate change, require our cities and regions to adapt to new challenges. The concept of the sponge city addresses precisely this: cities are designed to capture, store, and reuse rainwater where it falls, rather than quickly channelling it into sewers. Green spaces, green roofs, permeable soils, and infiltration systems act like a "sponge" that stores water, prevents flooding, and simultaneously improves the urban climate. This water is then available when needed, such as during prolonged dry periods.

In rural regions in particular, isolated individual measures are not enough. The idea of the sponge city is therefore extended to the sponge region, to make entire stretches of land resilient and liveable. A network of green, water, and infrastructure elements transforms cities and communities together into a sponge region that recognises and addresses the challenges of this network.