The designer who's trying to turn your city into a sponge


Your city is not prepared for what is to come. The classic way to deal with storm water is to drain it out of the city as quickly as possible through gutters, sewers and canals. But more and more, that strategy is breaking down: As the atmosphere warms, it can hold more moisture, sometimes leading to wetter storms that destroy this creaking infrastructure. Your city was built for the climate of 100, 200, 300 years ago, but that climate no longer exists.

The newest strategy in urban design, which originated in China, is to slow everything down. Since 2013, China has launched a national policy of turning its growing metropolises into sponge cities, which store stormwater rather than disposing of it. If engineers can slow the flow of that water and allow it to soak into the earth rather than run off – using rain gardens, spreading grounds, permeable pavers and urban wetlands – that simultaneously reduces flooding and Replenishes underlying aquifers. As the planet warms and drought deepens, this will become even more serious: The goal of sponge cities is to store water for a rainy day, or more accurately, a dry day.

“Whenever it rains, we save as much as possible,” says Kongjian Yu, champion of the concept and founder of Beijing design firm Tureenscape. “We slowed down the flow and let the earth absorb the water. A sponge city would become an adaptive city, a resilient water system, a porous landscape. A recent study found that, all told, cities across the United States could be sucking up billions of gallons of water a day because of China's lead and acceleration of sponge projects. “Sponge cities are an urgent, immediate solution that can help cities adapt to climate change, heat, floods, droughts,” says Yu.

This is what the Benzakitti Forest Park in Bangkok, Thailand looked like before and after its sponge transformation. (Move the slider to see the full change.)

After Yu was recently awarded the Oberlander Prize by the Cultural Landscape Foundation for his work on sponge cities, WIRED sat down with the landscape architect to talk about how making urban areas as spongy as possible can solve a lot of problems. Can solve. What can metropolitan cities do now to prepare for the immediate, and increasingly chaotic, environment of tomorrow? This conversation has been condensed and edited for clarity

Wired: One of the things that makes this concept so powerful is that you can do it at different scales. In Los Angeles, they have spreading grounds – hundreds of feet of open areas where water is allowed to soak into the aquifer – but they are also tearing up thin strips of roadside and planting greenery.

Kongjian Yu: A sponge city can turn on Any scale. Water is precious. If you have water in your backyard, you don't need to water your trees, you don't need to water your garden, because the water below – is your treasure. Here, It's at the individual, personal, community level.