Making cities 'spongy' could help fight flooding — by steering the water underground

This natural pond helps reserve precipitation in the ecological corridor of Qian'an, a city in China's Hebei province. Like many other Chinese cities, Qian'an used to fall victim to urban flooding during rainy seasons. But things have changed since 2015, when the city was included in a national pilot program for "sponge city" construction. (Mu Yu/Xinhua via Getty Images)

JINHUA, China — In the shade of a willow tree, Li Tao and his buddy dabble lines in a slow-moving river channel and occasionally pull out a tiny fish.

"It's good to have a place like this for people to relax," says Li, his shirt off in the midday heat.