Like anything else, Moderate water is great – urban dwellers need it to survive, but downpours can flood streets and homes. And as you may have noticed, climate change Not good in moderation. A warmer atmosphere holds more moisture, supercharged storm dump more water faster, which could flood city sewers built for the climate long ago. So you get the biblical floods that are engulfing cities around the world, from Zhengzhou, Chinaarrive Seoul, South Koreaarrive Cologne, Germanyarrive New York City.
In response, urban planners increasingly see cities as less like raincoats — designed to sweep water away as quickly as possible before it has a chance to build up — and more like sponges. By deploying thirsty green spaces and digging huge earthen bowls where water can gather and seep into the aquifers below, “sponge cities” are turning rain into an exploited asset. extraction instead of deportation.
Michael Kiparsky, director of the Wheeler Water Institute at the University of California, Berkeley, said: “Where there were forests, fields and swamps flooded with rainwater, they have been paved with stones and replaced with rain-proof surfaces. . . It’s hard materials like concrete pavement, asphalt, and roofs that will run down gutters, storm drains, and sewers.
Kiparsky continued: “The denser cities grow, the more impervious surfaces are used, the worse the effects of climate change become. “Once the capacity of these structures is exceeded, water begins to back up and its problems are exacerbated by the lack of natural absorptive capacity of the lands and vegetation. big thing”.
Any good city planner knows the value of green spaces, but traditionally they have been used primarily for public purposes. Sponge city designers also use them as a tool to manage increasingly intense rains. An inch of rain that falls in an hour is more likely to inundate stormwater infrastructure than an inch of water that falls in 24 hours — a problem for places like Pittsburgh, Pennsylvania, where hurricanes occur. significantly wetter over half a century. “The long and short part of it is: more intense and more frequent,” said Tony Igwe, senior group manager for stormwater at the Pittsburgh Water and Sewer Authority, which is competing with the city. “There’s a lot of work going on not just in Pittsburgh, but especially in the mid-Atlantic, to really look at those numbers over the next few years.”
