Design for Living: Seoul's daylighted inner-city stream

Fun time in the Cheonggyecheon Stream in central Seoul. Photo / Getty Images

Seoul is a city of 25 million and until about 20 years ago, everyone thought it really needed its expressways. But the ambitious mayor of the South Korean capital, Lee Myung-bak, had other ideas.

In a former life, he ran the construction company that built the elevated Cheonggye Expressway, a 1970s symbol of urban progress. But as a politician, he changed his mind. He saw the electoral value of being green, tore down the expressway, restored the original stream and created a new inner-city park.

Cheonggyecheon Stream opened in 2005 and quickly became a favourite with locals and tourists alike: an oasis of calm, a playground with swimming for kids of all ages, a venue for festival events. Later on, Lee became president, took bribes and then went to jail for corruption, but let's not allow that to tarnish this achievement.

Cheonggyecheon Stream in the evening. Photo / supplied

The process is called "daylighting" and it has been taken up all over the world. Seoul itself has now daylighted 15 streams. In the British city of Sheffield, the Porter Brook and the Sheaf River have been daylighted. In London, the Moselle was daylighted in 2013, although with unexpected consequences: the waterway turned out to be full of sewage.

Actually, that's quite common: many cities once had rivers that were buried to hide the pollution. La Bievre, in Paris, as one writer declared at the end of the 19th century, "flows slowly, oily and black, streaked with acids, dotted with soapy and putrid pustules".

It was, said one newspaper, a "once beautiful river" destined to be "walled up and bewitched like a sorceress during the Middle Ages, and in this strange and desolate valley … a new district of tall and flaming buildings will rise".

The same thing happened in Auckland's Queen St valley. The Waihorotiu Stream, once bountiful with eels and birdlife, became "an abomination, a pestiferous ditch and the receptacle of every imaginable filth". In the mid-19th century it was bricked up and built over.

But the Cheonggyecheon was filthy once too. Dirty waterways can be cleaned up.

The Auckland City Council looked at daylighting Waihorotiu in 2006 and the Auckland Regional Council and landscapers Boffa Miskell took another look the next year. Their proposals, for daylighting streams in Queen St and also in Freemans Bay and Parnell, still exist. The artist Chris Dews has imagined what Queen St might become too.

The climate crisis makes the task even more rewarding: daylighted streams offer urban respite from all the concrete and asphalt and provide passive cooling to combat "heat islands".

In the British town of Rochdale, daylighting the River Roch was proposed, to provide the downtown shopping district with a waterfront. Business owners were sceptical but they were won over by a different benefit: it would relieve the risk of flooding. Auckland shops face that issue too.

In Zurich, daylighting is well established. They call it bachkonzept, or the "stream concept", and although Seoul might have the world's most famous example, the Swiss have been doing it for 35 years. We could try a little harder.

Design for Living, a series about bright ideas that makes cities better, appears weekly in Canvas magazine.

A daylighted stream in Auckland, as envisaged in 2007. Image / Boffa Miskell

Queen St with a daylighted Waihorotiu, as imagined by artist Chris Dews. Image / Chris Dews