Urban waterways: Seoul peels back the pavement and reveals a river

Other cities take note as expressway yields to stream

About half the world’s population presently lives in cities, and the proportion will increase to two thirds by mid-century. This trend is good for the natural environment, but also highlights the need to maintain the human environment within rapidly expanding urban areas.

The New York Times recently highlighted a seemingly unlikely success: the city of Seoul recovered three miles of river that used to bisect the city before being covered over with pavement and elevated expressways. The project is part of a growing movement to reclaim waterways in urban areas.

The Seoul project was expensive and the end result hardly fits anyone’s definition of unsullied nature. Almost all of the water that now flows between the mostly concrete banks of the Cheonggyecheon is pumped there through seven miles of pipes. The project cost a total of $384 million.

Rather than being derided as expensive folly, however, the project is being studied and copied by municipalities all over the world. The reason is fairly simple: citizens love the reclaimed space. The politician who spearheaded the project is now president of Korea.

The project has also yielded more readily quantifiable benefits.

Data show that the ecosystem along the Cheonggyecheon has been greatly enriched, with the number of fish species increasing to 25 from 4. Bird species have multiplied to 36 from 6, and insect species to 192 from 15.

The recovery project, which removed three miles of elevated highway as well, also substantially cut air pollution from cars along the corridor and reduced air temperatures. Small-particle air pollution along the corridor dropped to 48 micrograms per cubic meter from 74, and summer temperatures are now often five degrees cooler than those of nearby areas, according to data cited by city officials.

And even with the loss of some vehicle lanes, traffic speeds have picked up because of related transportation changes like expanded bus service, restrictions on cars and higher parking fees.

“We’ve basically gone from a car-oriented city to a human-oriented city,” said Lee In-keun, Seoul’s assistant mayor for infrastructure, who has been invited to places as distant as Los Angeles to describe the project to other urban planners.

Some 90,000 pedestrians visit the stream banks on an average day.

Cities are a core solution to climate change, and smart development like the reclamation of the Cheonggyecheon will help to ensure that they become increasingly healthy and green even as they grow.

Image by Flickr user madmarv00.