Daylighting urban streams has long made sense aesthetically, but now the environmental, traffic calming, and air pollution benefits can be quantified based on new studies of the famous Cheonggyecheon running through downtown Seoul.
From the New York Times:
Cities from San Antonio to Singapore have been resuscitating rivers and turning storm drains into streams. In Los Angeles, residents’ groups and some elected officials are looking anew at buried or concrete-lined creeks as assets instead of inconveniences, inspired partly by Seoul’s example.
By building green corridors around the exposed waters, cities hope to attract affluent and educated workers and residents who appreciate the feel of a natural environment in an urban setting.
Environmentalists point out other benefits. Open watercourses handle flooding rains better than buried sewers do, a big consideration as global warming leads to heavier downpours. The streams also tend to cool areas overheated by sun-baked asphalt and to nourish greenery that lures wildlife as well as pedestrians.
But four years after the stream was uncovered, city officials say, the environmental benefits can now be quantified. Data show that the ecosystem along the Cheonggyecheon (pronounced chung-gye-chun) 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.
The note about streams handling flooding better couldn’t be truer. Here in Atlanta, we have received over 15 inches of water in a week, soon to be followed by even more. Having received another two inches of rain today, we can personally say that the capacity of open streams and brooks to take on the extra water is irreplaceable. It is intelligent economically, practically, and ecologically. Cheonggyecheon is an enormous urban renewal project that Seoul has urgently developed into a green space and is excellent proof that even a megapolis is able to make large-scale changes to its primary infrastructure. Although the changes are not immediately evident, they clearly do take effect in the long-run; this is the sort of attitude more people should take note of rather than urging immediate economic benefit.
JVG Engineering
Atlanta, GA