A sponge city is a new urban construction model for flood management, strengthening ecological infrastructure and drainage systems, proposed by Chinese researchers in early 2000 and accepted by the Chinese Communist Party (CCP) and the State Council as urbanism policy in 2014. It can alleviate urban flooding, water resources shortage, and the urban heat island effect and improve the ecological environment and biodiversity by absorbing and capturing rain water and utilizing it to reduce floods. Rain water harvested can be repurposed for irrigation and for home use. It is a form of a sustainable drainage system on an urban scale and beyond. Sponge city policies are a set of nature based solutions that use natural landscapes to catch, store and clean water; the concept has been inspired by an