Come hell or high water, the residents of St. Kjeld, a Copenhagen neighborhood, will be ready. Actually, skip the hell part. But when the next megastorm hits the Danish capital, St. Kjeld’s residents should be safe and dry. That’s because as of December, they live in the world’s first climate-change-adapted neighborhood.
“St. Kjeld’s transformation shows what can be done if you take climate change seriously,” says Morten Kabell, Copenhagen’s deputy mayor in charge of environment and technology. In truth, after a catastrophic cloudburst in 2011 that resulted in damage of about $1 billion, this windy port city had little choice but to find ways of protecting itself.
“Climate change is a reality and we have to be prepared for floods, storms and rising sea levels,” says René Sommer Lindsay, the city official in charge of St. Kjeld’s transformation. “The cloudburst was really a wake-up call. We said, ‘Instead of doing pinpoint projects, let’s develop a rainwater master plan.’ Rainwater is only a problem if it goes where you don’t want it to go.” That gave city planners the option of adding “gray infrastructure” — technologies that, in this case, would have included essentially more and bigger sewers — or designing “green,” nature-based structures that collect the water and lead it away.
They went for the green option. “Adding sewers is insanely costly, so a green-and-blue [vegetation and water] approach is more economical,” notes Esben Alslund-Lanthén, an analyst at the Copenhagen-based sustainability think tank Sustainia. There was just one challenge: No city has ever tried climate-change-adapting a whole neighborhood using just plants and water. “It’s a huge amount of water that we’ll have to redirect when the next cloudburst hits,” says Flemming Rafn Thomsen of Tredje Natur, the Danish architecture firm chosen for the project. “We looked at St. Kjeld and thought, ‘That’s a lot of asphalt with no function. We can use some of that space for water.’” On top of having little function, the asphalt gave St. Kjeld, a somewhat rundown working-class neighborhood, an even more depressing feel.
The answer, Rafn Thomsen and the city decided, was to tear up the neighborhood’s squares and replace their asphalt covering with what’s essentially a hilly, grassy carpet interspersed with walking paths. Should a storm, flood or rising sea levels hit the Danish capital again, the bucolic mini-parks will turn into water basins, the hills essentially functioning as the sides of a bowl. Thanks to a new pipe system, the squares will even be able to collect water from surrounding buildings’ roofs. Surrounding streets will, for their part, be turned into “cloudburst boulevards.” Under ordinary circumstances, they’ll just be ordinary streets with raised sidewalks, but during floods and megastorms, they’ll become canals, channeling rainwater away from the squares to the harbor. Millions of gallons of water will be dispatched back to the harbor on such aboveground waterways, St. Kjeld becoming a temporary Venice.