China's 'sponge cities' tested by devastating Beijing floods
Since 2013, China has been trying to make cities like Beijing more flood-proof by replacing roads, pavements and rooftops with natural materials like soil that absorb water, and by giving more space to water bodies like lakes to absorb rainwater.To get more news about
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But despite these measures, massive rainfall in recent weeks has caused flooding that has killed at least 33 people, destroyed tens of thousands of homes and closed the Chinese capital's second busiest airport.
Experts told Climate Home that the flooding shows the limited progress China has made on its plan to invest $1 trillion in sponge cities by 2030 - with the city still largely made of concrete.
Sponge airport overwhelmed
Even new infrastructure built with the sponge city concept in mind could not cope with the rain.
Daxing Airport opened a few months before the Covid-19 pandemic. Its builders dubbed it a "sponge airport" because it was equipped with plants on the roof, a huge wetland and an artificial lake the size of over 1,000 Olympic swimming pools.
Despite these measures, the runways flooded on 30 July, forcing the cancellation of more than 50 flights.
Water diverted
The government tried to collect the rain in 155 reservoirs in the Hai River basin, but the measure proved ineffective in controlling the deluge.
About 50 years ago, the basin - a natural sponge - was enclosed with dams and reservoirs to manage the flow of water.
In recent years, however, these structures have exacerbated flooding as climate change has increased the frequency and intensity of extreme rainfall. These structures are overflowing, collapsing and authorities have been blowing them up to alleviate flooding.
Reuters reported that floodwater trapped in reservoirs in Zhuozhuo, a small town about 80km from Beijing, was diverted to low-lying populated areas to flush rainwater out of the country's capital.
Zhuozhou residents were angry at the government's response, Reuters reported. The government responded by shutting down criticism on social media.
More work needed
Experts argued that these problems show that rather than abandoning the sponge city project, China and Beijing need to redouble their efforts and improve it.
Kongjian Yu is the founder of Turenscape, a company involved in the project. He says that only "maybe 1% or 10%" of the city has been converted into a sponge city.
The government's target is 20% by 2030. "We still have a long way to go," he said.
Yu added that sponge cities are worthwhile not only for flood control, but also for drought management and groundwater replenishment.
