Sponge city

Sponge city (Chinese: 海绵城市) is an urban planning model in China, first proposed by Kongjian Yu, that emphasizes the implementation of hydro-ecological infrastructure. Sponge cities focus on flood prevention and stormwater management via green infrastructure instead of purely relying on drainage systems. Urban flooding, water shortages, and the heat island effect can be alleviated by having more urban parks, gardens, green spaces, wetlands, nature strips, and permeable paving, which will both improve ecological biodiversity for urban wildlife and reduce flash floods by serving as reservoirs for capturing, retaining, and absorbing excess stormwater.This urban planning model has been accepted by the Chinese Communist Party (CCP) and the State Council as a nationwide urban construction policy in 2014.

Sponge city design is a set of nature-based solutions that use natural landscapes to catch, store and clean water; the concept has been inspired by ancient wisdom of adaptation to climate challenges, particularly in the monsoon regions in southeastern China. According to Chinese authorities, "Sponge cities are part of a worldwide movement that goes by various names: 'green infrastructure' in Europe, 'low-impact development' (LID) in the United States, 'water-sensitive urban design' in Australia, 'natural infrastructure' in Peru, 'nature-based solutions' in Canada. However, sponge cities are often mixed up with these concepts, especially LID, but have major differences. Sponge cities use ecological and technical concepts whereas LID uses mostly technical concepts. Sponge city design assists in water quality, remediation, construction of habitats, and more beyond flood mitigation and stormwater regulation. Hydro-ecological infrastructure and nature is interconnected across cities and watersheds with the sponge city design. This model preserves and restores ecosystems, allowing aquatic ecosystems to live in tandem with humans. In contrast to industrial management, in which people confine water with levees, channels and asphalt and rush it off the land as quickly as possible, these newer approaches seek to restore water's natural tendency to linger in places like wetlands and floodplains."