Chinese engineers and urban planners have decided to depart from traditional ‘grey infrastructure’ like dams, stormwater drains and catch basins that funnel excess water from our streets. Instead, Kongjian Yu, dean of Peking University’s College of Architecture, and his colleagues have decided to turn their cities into ‘sponges’.
Yu has championed the radical idea for two decades. He believes that replacing the millions of tons of concrete that channel water out of our cities and into nearby dams with more natural alternatives will save many lives and homes.
Extreme weather events like monsoons and floods can destroy homes and infrastructure with devastating speed and ferocity. Rapidly rising water levels near human settlements cause billions of dollar’s worth of damage to property every year.
According to a 2017 report by the Norwegian Refugee Council (NRC), 14 million people will be displaced every year for the next twenty years due to extreme climate.
In 2013, Chinese officials started trialing Yu’s idea. The previous year, catastrophic flooding in Beijing forced nearly 80 000 thousand residents to evacuate their homes. After just a day, more than 70 individuals lost their lives and an estimated $1.6 billion in damages was inflicted upon the capital.
In theory, sponge cities would use natural features like wetlands, creeks and floodplains to collect and redirect excess water slowly and manageably. Yu and his colleagues believe that the massive networks of grey infrastructure used in modern urban planning fight nature are doomed to fail in time.
Yu says that rainwater collected in sponge cities could be incorporated into irrigation systems and street cleaning while its evaporation would also cool down the city. Vegetation and permeable soil similar to wetlands would also filter and clean water naturally while lessening the burden on drinking water filtration systems, according to the Chinese-born ecologist.
If only one percent of the land was devoted to drainage, almost all flood damage could be avoided, says Yu. An increase to around six percent would almost completely remove the fear of dangerous flooding.
Most can agree that wide open, green spaces like wetlands are more pleasant to look at than stormwater drains too. Not only would a cityscape look better, but the region’s fauna and flora would also benefit. University of Nottingham Ningbo, associate professor, Faith Chan, said that when wetlands and forests prosper, so does wildlife.
Chan also pointed out that communities agree that urban parks improve their quality of life. He helped create an eco-corridor in a previously uninhabitable area of Ningbo, an hour outside of Shanghai.
The post-industrial area was deemed ‘uninhabitable’ by officials but Chan, who has studied sponge cities extensively, helped turn the previously desolate region into an area full of indigenous plant life and meandering waterways.