Urban planning approach designed to absorb, store and reuse rainwater to reduce flood risk.
The sponge city is an urban planning approach aimed at making the urban fabric able to absorb, store and reuse rainwater, rather than evacuating it quickly through networks that saturate during heavy rain. It mobilises nature-based solutions, permeable surfaces, vegetated roofs and swales, restored wetlands, retention basins, to reduce runoff and pluvial flood risk. The concept, popularised by Chinese urban policy, fits an adaptation-to-climate-change logic. For insurance, the sponge city acts on exposure upstream of risk transfer: by reducing the probability and severity of urban floods, it improves the insurability of territories subject to intensifying rainfall. It illustrates the shift from a purely indemnity role toward an insurance interest in prevention and planning, whose benefits show up in long-term loss experience.
A district redeveloped as a sponge city, with basins and permeable surfaces, can significantly reduce pluvial flood losses during intense storm episodes.
sponge city, ville éponge, ville perméable