A render of Xinyuexie Park, which is designed to preserve and improve how the city copes with storm water. Photograph: Obermeyer
...Nanganqu Park..., which lies in the east near a... large iron and steel company..., was a... dirty drainage ditch... in the ...1980s.... It became a... park... in the ...1990s... and was last year ...transformed... into a ...***“sponge site”***..., with ...permeable pavements..., rain gardens,... grass swales..., artificial ponds... and... wetlands. ...The idea is that these features... absorb excessive ...rainfall through ...soil infiltration... and ...retain it in ...underground tunnels... and ...storage tanks..., ...only discharging... it into the river ...once water levels there... are low enough...