Cheongye Stream, known as Cheonggyecheon (청계천) in Korean, runs eastward through the heart of Seoul, passing through 13 neighborhoods in four districts of the capital of South Korea. Throughout its history, the stream played different roles in the city until it was covered by an elevated highway in the 1970s. For over 30 years, this natural artery remained hidden. It was not until 2003 that the city government launched a restoration project to reintegrate this urban waterway into the city fabric, revitalize the local economy, and revive the area's history and culture. The revitalization efforts were led by Mikyoung Kim Design. Since the project's completion in 2005, it quickly became one of Seoul's most visited tourist attractions. Moreover, it has become a focal point for ample urban research, with many studies offering positive assessments of the impact it had on Seoul's urban, economic, and ecological context.
The stream's historical significance can be divided into 3 main phases: The first dates to the Joseon Dynasty in the 14th century. During this period, Seoul became the capital of Korea, and the stream played a critical role as a source of water and a drainage system for its inhabitants. The second phase came in the 1960s following the Korean War. This era was marked by shanty towns that settled along its length using the stream as sewage and causing heavy pollution problems. This situation gave way to the third phase where concrete was poured over the stream to construct a 50-meter-wide road that ran for about 6.0 km. Finally, in 1976, an elevated highway was built over that road to alleviate traffic problems in the capital of a country transforming from post-war poverty to a modern industrial powerhouse.
Despite this progress, covering the stream came at a significant environmental cost. Seoul's urban planning during the mid-20th century focused on economic growth and largely ignored the ecological implications of sealing away a natural waterway. By the late 20th century, Cheongye Stream had become a focal point of Seoul's environmental challenges. In the 1980s concerns arose regarding increasing health risks from the polluted water under the road, air pollution caused by traffic, and the increasingly deteriorated stability of the highway's structure. The concrete cover not only masked a crucial part of the city's natural heritage but also worsened the quality of urban life for residents. The lack of open space, poor air quality, and traffic congestion made the area unattractive for both residents and businesses.
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Revitalizing Urban Ecosystems: 4 Projects Reconnecting Cities with Their Water HeritageBy the early 2000s, city officials recognized the need to address the mounting environmental problems associated with the buried Stream. The question was: how could this urban waterway be revitalized in a city now dominated by concrete and cars?
That is why in 2003, Seoul embarked on an ambitious project to restore Cheongye Stream as part of a broader urban renewal initiative. The objective was not merely about exposing the stream; it was a deliberate effort to re-naturalize the waterway, reconnect the city with its environmental and historical heritage, and foster sustainable urban development. The 27-month-long project involved exposing the stream to the sunlight once more by demolishing the concrete road and highway above it. Later, efforts began to restore the water quality, flow, and the area's ecology over a length of approximately 5.84 km.
Because of highly permeable soil, the original Cheongye stream was a seasonal waterway that flowed only when it rained. Hence, supplying water to it to ensure a constant flow was one of the most controversial issues. Because of this both sides of the stream were permeated to prevent the water from infiltrating the soil below. To source the water, it was decided to supply a daily amount of 12,000 cubic meters of water, which would ensure an average depth of 40 cm. A newly implemented purification system sourced part of the water from the Han River, 15 km away, while the rest came from underground water drawn from subway tunnels with electric pumps.
Another key goal was to restore the riparian ecosystem of the stream, referring to the lands along the edge of rivers or water bodies, which sustain various life forms and provide critical ecosystem functions. For this, the city had to look for reference sites with similar topography and vegetation as Cheongye. Due to South Korea's high industrialization, it was difficult to find pristine sites to serve as examples. The designers had to look into the Yongsoo and Youdong streams as references to evaluate their characteristics, both more than 100 km away from the Cheongye stream. This informed the creation of vegetation profiles that would be used to replant native species in the area.
The effort to create a constant water flow plus the restoration of native vegetation was complemented with architectural design, displaying sinuosity and wide pedestrian walkways that promoted walking and doubled as exhibition spaces. Despite the overall positive effects of the initiative, it was not welcomed by everyone. Many still avoid using the term "renaturalization' in reference to the stream, as some people consider this project to be an artificial urban waterfront rather than an ecologically restored stream. Despite this, by 2020, research already suggested that, after the restorative treatment, the species richness generally increased. The stream was already hosting 260 species of plants, 20 species of fish, 10 species of amphibians and reptiles, and 33 species of birds, all new to the area. At the same time, the species of insects in the area increased by 35%.
Regarding construction and land use, both showed accelerated growth after the project was completed. Research suggests that by 2006, only a year after the completion of the project, rents for offices near the stream increased 13 %, while land prices in redevelopment districts increased between 35 to 80%. Along with these changes, over 5 years since the project opened, land use shifted from mainly industrial to offices, commercial, hotels, and educational institutions.
Socially, the revitalized Stream became a popular public space for residents and tourists alike. The stream's linear park design, offers a serene environment for walking, recreation, and relaxation, serving as a natural escape in the middle of a bustling metropolis. The project also had a positive impact on the mental health and well-being of residents by increasing access to green spaces and promoting outdoor activities.
While the project received criticism for its high costs and the initial displacement of some businesses, it has also demonstrated significant long-term benefits. The Cheongye Stream serves as an example of sustainable urban regeneration, illustrating the complexities involved in balancing urban development with environmental goals. As cities around the world face similar challenges, the Cheongye Stream project provides valuable insights into how urban progress can be pursued alongside environmental sustainability, reintegrating urban infrastructures into the city fabric, and highlighting the positive effects of creating space for water and wet ecosystems in urban environments.
This feature is part of an ArchDaily series titled AD Narratives, where we share the story behind a selected project, diving into its particularities. Every month, we explore new constructions from around the world, highlighting their story and how they came to be. We also talk to the architects, builders, and community, seeking to underline their personal experiences. As always, at ArchDaily, we highly appreciate the input of our readers. If you think we should feature a certain project, please submit your suggestions.
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