City River Restoration at its Best

Early depiction of the Cheonggyecheon River, Undated

The Historical Problem

The Cheonggyecheon (CH) was once a naturally formed stream, long before the Joseon Dynasty designated South Korea’s Capital, Seoul, along its banks in 1394 (Cheong Gye Cheon Tour, 2013). Throughout the City’s long history there has always been a connection to water, most likely because of its proximity to the mountains and several tributaries. This is increasingly evident with drawings and paintings continually recognizing important events along the CH. Throughout every year’s dry spell in the spring and fall, along with flooding in the summer months, there continues to be activity alongside the CH even to this day.

There were often businesses and homes along this river, making it a place of gathering, but also a place of inundation and destruction. Because of this reason, the Joseon Dynasty constructed a drainage system as part of the refurbishment of the city. It was even dredged in 1406 by the support of the third king, Taejong (Cheong Gye Cheon Tour, 2013). 

In 1411, an authority was put in place to overhaul the stream further. This required over 50,000 men per day creating stone embankments for the mainstream and building up of stone bridges, specifically the Gwangtonggyo and Hyejeonggyo. The main stream was overhauled under King Taejong, and tributaries were focused on with King Sejong’s reign to prevent flooding. in 1441 the first water level reading was taken to measure flooding, a tradition and scientific method used for years to come (Cheong Gye Cheon Tour, 2013).     

While the CH started out pristine, the completion of these stream modifications also brought about human activity, subsequent wastewater as well as trash from local gatherings and business. At around this point, Seoul’s growing population had hit a threshold. The king declared utilization of the CH for the growing needs of his people (Cheong Gye Cheon Tour, 2013).

For the next half century or so, the stream remained capable of carrying out wastewater for about 100,000 Seoulites. However this capacity was quickly overwhelmed after the Japanese invasion in 1592 and the Manchu War in 1636, with the jump in Seoul’s population from 80,000 to 190,000 within a few decades. This obviously led to the complete shutdown of the CH's ecological capabilities (Cheong Gye Cheon Tour, 2013). 


With this population rise, there was increased farming near the tributaries as well as run off from farther upstream due to logging. As a result,  the CH had become filled with earth and sand by 1725. The problem became so dire that an office of dredging was appointed in 1759 which then dredged the main stream accordingly along with all of its tributaries in 1760. This effort required mobilizing 200,000 men per day (Cheong Gye Cheon Tour, 2013). 

From around 1918 onwards, Japanese occupiers were increasingly focused on redeveloping the river area. There were plans to cover the river on many occasions, for a housing development or even an elevated railroad and roadway. Japanese rulers thought this course of action could show their central presence and power, thinking that Seoul could one day become an advantageous base for wars with the US and China. One section of the river was covered up during this time, but many more plans went unmet due to financial restrictions (Cheong Gye Cheon Tour, 2013).

By the end of World War II, the nation was liberated from the Japanese. However, the CH was still seriously neglected, filled with trash and dirt. After the Korean War from 1950-1953 even more people came to Seoul, starting the mass migration to the city for new opportunities. This created all kinds of communities settling near the CH. These populations started becoming sick from the localized pollution, and this had a real tarnishing effect on the image of Seoul during the 50’s (Cheong Gye Cheon Tour, 2013).                    

Things were so precarious at this point, with the often dangerous makeshift infrastructure and drowning toxic fumes, that the government made a bold decision to redevelop completely and pave over the problem-ridden CH. In 1958 an elevated highway was built, extending over top of this central area completely in 1971. All the room along the river banks was created through the demolition of the makeshift houses, making way for modern high-rise buildings in a wave of new development. With the modernization of this commercial zone there came congestion, noise and the creation of the busiest sector in Seoul. This area can be seen as one of intense poverty in the 1950’s, successful industrialization and modernization in the 60’s and 70’s, but then a recurrence of health and environmental issues in the 80’s and 90’s with new pollution sources (Cheong Gye Cheon Tour, 2013).


The Solution    

The Cheonggyecheon has always been an important downtown location in Seoul. It has been the heart of the city for over five centuries, managing Seoul’s ever growing problems but also offering valuable green space, with the status of its health often changing.

With this in mind, Seoul’s government and public planning sector went through a dramatic paradigm shift in the late 90’s and early 2000’s, wanting to restore their downtown to what it once was. They wanted to focus on green space and environmental health as they began to emerge into the spotlight of notable developing cities.  They had a radical idea to remove their large transportation artery running through downtown, providing an opportunity to clean up the CH, hopefully making it a highlight rather than a detriment. The government developed the Cheonggyecheon Restoration project headquarters in 2002 to spearhead this initiative and to see if the river could even be revived at all (Cheong Gye Cheon Tour, 2013). 

Since 2003, the restoration project headquarters has promoted efficiency of communication and development along with the development of neighboring buildings in Seun Arcade (Cheong Gye Cheon Tour, 2013). There was a Restoration Research Corps put in place to carry out research regarding the basic materials and schemes to most effectively complete this restoration. This took place from 2003 to 2006, and looked specifically at the needs for restoring the stream, reviewing similar case studies, reorganization of the urban traffic system, removal of existing infrastructure over the stream, actual restoration of the stream, and creating a management plan for the downtown section (Cheong Gye Cheon Tour, 2013). 

The Research Corps made major efforts for community input, holding public panel discussions. They also held seminars to take input from experts of pollution control, restoration processes and economic evaluation of environmental factors. They also carried out diverse PR activities to get the word out. Some of the most notable activities was the seminar at Toji Culture Center in 2002, with over 400 participants on the subject of Opening of New Chapter of with Restoration of the Cheonggyecheon (Cheong Gye Cheon Tour, 2013).

Another notable event was the international symposium cosponsored by the Citizen's Committee, the City of Seoul and the UNEP Korea. This seminar showed the restoration of streams in similar cases, providing urban development strategies in foreign countries. This meeting helped to gain support from the public for this project. Other events included the Officials Training Institute with 500 plus city councilors, civic committee members and others. Other meetings were held throughout 2003 for review of the project, and implementation in 2004 (Cheong Gye Cheon Tour, 2013). These larger events probably contributed considerably to the public acceptance and appreciation of this project today. 

The Seoul Metropolitan Government established the Cheonggyecheon Restoration Centre to act as a focusing centre for the projects research, development and planning. The Cheonggyecheon Restoration Citizens’s Committee also helped in providing public input, conveying concerns and information sessions. (Cheonggyechean Restoration Project, Case Study, 2013).

Through years of overhauling aging infrastructure, and removing debris from an often overused area in the past century, the project is now complete. Since its public opening on October 2005, the CH has been quite popular with residents and tourists of Seoul. It has even drawn an estimated 18.1 million visitors by the end of 2008. The Cheonggyecheon Museum, along its embankment, also hosts permanent and temporary exhibitions of the area’s history and restoration (Cheonggyecheon Restoration Project, Evaluation, 2011). 


Traffic has also been reorganized in an effective way because of this project, leading to one of the most innovative subway and bus networks in the world. Speeds in this central business district have only slowed by 12.3 percent. Considering that their main transportation hub in the center was removed, this represents a very effective reorganization of resources (Cheonggyecheon Restoration Project, Evaluation, 2011). Bus ridership increased 15.1% and subway ridership increased 3.3% from before and after the project (Landscape Architecture Foundation, 2013).

There are also distinct zones of the stream restoration project. Zone 1 includes a highlight of historical bridges. Zone 2 is the urban and cultural recreation area providing artwork, maps and a long walkway with seating. Zone 3 provides the natural ecologies, industrial mementoes, as well as wetlands designated as ecological conservation areas (Cheonggyechean Restoration Project, Case Study, 2013).

Technology and Restoration Effectiveness 

The water quality of the river has also dramatically improved since the restoration. The water that now flows into the Cheonggyecheon is of a Class-2 standard according to the Korean water standards, just below Class-1 which is the the highest environmental standard for freshwater fish. The water is safe for recreational use, but it is not drinkable due to issues of E. coli and turbidity. The water filtration process is shown below (Cheong Gye Cheon Tour, 2013).

The water temperature in the river has gone down 10-13%, or 3-4 Celsius, in the summer months. Scientists believe this is due to the reintroduction of a wind tunnel in downtown Seoul, with the wind speed increasing by 2.2-7.1%. The decrease in vehicles nearby, also led to this reduction in water temperature. It is expected for this heat island in the city to be reduced further by the extensive planting of aquatic plants in this river (Cheong Gye Cheon Tour, 2013).


This structurally supported river now also provides protection for up to a 200-year flood event, or a flow rate of 188 mm/hr. Biodiversity in the city has also dramatically increased. Overall species biodiversity increased by 639% between the pre-restoration work in 2003 to the end of 2008 and the completion of the project. Plant species increased from 62 to 308, fish species from 4 to 25 and bird species from 6 to 36, with the most noticeable jump of insect species from 15 to 192 (Landscape Architecture Foundation, 2013).

There have also been dramatic changes in air quality, highly noted because of the common occurrence of respiratory disease in the area pre-restoration. Small-particle air pollution was reduced by 35%, from 74 to 48 micrograms per cubic meter.

The number of businesses also increased in this area by 3.5% from 2002 to 2003. The number of working people also increased in this area by 0.8%, compared to the decrease in downtown Seoul of 2.6%. This is definitely a step in the right direction for economic growth of the downtown sector. The CH has also been found to attract 64,000 visitors a day, approximately 1,400 who are foreign and spend on average $1.9 million USD in the Seoul economy annually (Landscape Architecture Foundation, 2013).

The project also promoted relationships between waterways. The CH eventually runs into the Jungraecheon river, which leads to the Han River. This intersecting point was designated an ecological conservation area. Since the CH only has water during the summer rainy season, it is seasonly pumped from the Han river for consistent flow. Native willow swamps, shallows and marshes were created in 29 different areas along the stream to promote habitat for fish, amphibians, insects and birds. A fish spawning area was also established at the intersection of the CH and Jungnangcheon (Landscape Architecture Foundation, 2013). Overall, a major success on many different ecological levels. 

Public Acceptance of Project

Public acceptance and analysis with ten official respondent groups indicated that 66.8% made positive remarks, with 77.6% showing positive forecasts for the developments future. There was a general lag in business during the restoration years, but this has since increased dramatically, with foot traffic and rental costs rising higher and higher (Cheong Gye Cheon Tour, 2013).


How do projects rapidly get developed and where do they get delayed? 

Projects often get delayed because of financial needs or lack of public support, luckily this project had exceptional support in both areas. I think another key to the success of this project was the future business development incentive in this quarter of the city. With 43 cities over 1 million in size, within a 3 hour flight from Seoul, they wanted to make this area a foreign investment promotion zone. Seoul Government provides tax benefits and business authorization easily for foreign businesses, as well as providing social support with high end foreign schools. The area is already drawing international acclaim in other industries like entertainment and fashion as well (Cheong Gye Cheon Tour, 2013). When green space, environmental restoration and business promotion are tied together, it makes for a very compelling development project. 

Financial Assessment

The Cheonggyecheon Expressway would have required $90 million USD and three years of repairs to adequately update its aging structure. The CH stream restoration project totaled just under $370 million USD, but while costing more initially it has served as a major catalyst for city investment in this area. Estimates of about $1.98 billion USD have been made to the area, which otherwise would likely not have been invested (Landscape Architecture Foundation, 2013). 


Is the project replicable? Main learning objectives?

This is an incredibly bold project, unfurled by the local government over several years. They did an impressive job of transitioning this downtown district into something more viable for the population and business. Could this be possible somewhere else? It could, but there needs to be proper management and passion to drive a project like this forward. Organization at a government level, and public support at a large scale made this a success. This environmental project had the right potential to transform the image of Seoul just as it was needing it.

Cheonggyechean Restoration Project, Case Study. Rivers By Design. 2013. <>.                          

Cheonggyecheon Restoration Project. Evaluation. January 2011. <>.

Cheonggyecheon Stream Restoration Project. Landscape Performance Benefits. Landscape Architecture Foundation. 2013. <>.

Cheong Gye Cheon Tour. Seoul Metropolitan Facilities Management Corporation. 2013. <>.

Seoul’s Cheonggyecheon Stream. Discovering Korea. 2013. <>.