Heavy rain, floods bring renewed calls in China for 'sponge cities'

Heavy rain has lashed more than 10 cities in the Chinese province of Shandong since the weekend, inundating streets, disrupting traffic and renewing calls for better drainage in built-up areas where concrete and asphalt trap water.

The weather bureau issued thunderstorm alerts on Monday as vehicles in the northeastern province were stranded in waist-deep water, a video posted on the Weibo social media site showed.

Shandong, which is China's second-most-populous province with more than 100 million people, has reported disruption to train services since Sunday, after it was hit by its first heavy downpours of the rainy season that began weeks ago in southern China.

Every summer, China is prone to floods that trigger landslides and swamp farmlands and cities, where rapid development and urbanisation often block off natural drainage systems, scientists say.

Climate change is exacerbating the impact.

Weather expert Zhang Jianyun told a climate change and extreme weather forum on Sunday that it was necessary to plan and intensively use underground spaces for drainage, storage and water treatment, especially in big cities.

"Give floods a way out," Zhang said.

Low-impact development and construction of "sponge cities" would also help reduce flood risk, Zhang said.

China launched a programme in 2015 to create "sponge cities" that can safely retain and drain more rainwater, with permeable asphalt and pavements among the potential technological solutions.

Official data shows that about 98 percent of China's 654 major cities are vulnerable to flooding and water-logging, with rapid growth in recent decades creating urban sprawls that covered floodplains with impermeable concrete.

Last summer, Henan's provincial capital of Zhengzhou experienced record rainfall that paralysed the city with floods that killed more than 300 people.

- Reuters