A River Runs Under It

By Phil Nicodemus

The Cheonggyecheon River, which runs through the center of South Korea’s capital, Seoul, is a relatively small, seasonal stream that has become one of the most shining success stories of urban river restoration to date. In 2005, the city of Seoul finished it’s 950 million dollar project to transform the river from a sewer hidden under a road, into a pleasant, lush, 3.5 mile long pedestrian park that snakes through the city’s center. While it was a mammoth urban project that took years to plan and implement, follow up studies have shown that Seoul is still reaping huge benefits from the project, over a decade later.

The basis of the restoration project was to remove the crumbling Cheonggye highway built over the river (a process known as ‘daylighting’) and build a sunken, natural corridor of tranquil park space in its place. Ecologically, upon completion the project immediately jump started bio-diversity in the river, boosting the number of insect species  from 17 to a whopping 192. Fish jumped from 4 recorded species to 25, and birds went from 6 to 36 species.  Opening up the stream and installing the park cooled the surrounding area in the city by 3.6℃ (around 7 ℉), and significantly reduced air and water pollution, dropping local levels of airborne particulate matter by about 20%, and dramatically increasing the amount of dissolved oxygen in the water, something critically important for aquatic life. And, perhaps most appealing to city officials, is the fact that the Cheonggyecheon has blossomed into one of the most popular tourist attractions in Seoul, with over 64,000 visitors per day enjoying the park and providing a boon to the local economy.


The Cheonggyecheon restoration was officially proposed in 2002 by then Seoul mayor Lee Myung-bak. The aim was to finally address the long ignored issue of the dirty, neglected stream and the increasingly expensive highway that was built on concrete supports that straddled the river, designed to obscure the river from view, and provide infrastructure for a city growing at a blistering pace. Typically, we think of urban growth and development as advancement, and the natural world as our past. The Cheonggyecheon project demonstrates how wrong that notion is, (especially considering that removing the old highway actually improved traffic around the area, often suggested as a real life example of ‘Braess’ Paradox’). The upfront costs might have seemed daunting, but the Cheonggyecheon restoration proves that rather than looking at urban waterways as undesired obstacles, smart ideas and planning can use nature and park space as an important urban resource, one that can greatly improve the lives of the city dwellers who, at the end of the day, stand to benefit the most.

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