Mojeon Bridge crossing Cheonggyecheon (2012)
|- left||Seongbukcheon, Jeongneungcheon|
|Source||Suseongdong Valley in Mount Inwang|
|- location||Ogin, Jongno, Seoul|
|- location||Yongdap, Seongdong, Seoul|
|Length||10.92 km (7 mi) |
|Basin||50.96 km2 (20 sq mi) |
Cheonggyecheon (Hangul: ) is a 10.9-kilometre-long (6.8 mi), modern public recreation space in downtown Seoul, South Korea. The massive urban renewal project is on the site of a stream that flowed before the rapid post-war economic development caused it to be covered by transportation infrastructure. The $900 million project initially attracted much public criticism but, after opening in 2005, has become popular among residents and tourists.
Cheonggyecheon is an 8.4 km (5.2 mi) creek flowing west to east through downtown Seoul, and then meeting Jungnangcheon, which connects to the Han River and empties into the Yellow Sea. During the presidency of Park Chung-hee, Cheonggyecheon was covered with concrete for roads. In 1968, an elevated highway was built over it.
The stream was named Gaecheon ("open stream") after the first refurbishment project to construct a drainage system during the Joseon Dynasty. The work, which included dredging and bolstering the banks of the stream and building the bridges, was carried out every 2-3 years during this period from the reign of Taejong, the third king of the Joseon Dynasty. King Yeonjo especially undertook the refurbishment work as a national project.
Gacheon was renamed to Cheonggyecheon, its current name, during the period when Japan ruled by Hirohito dominated Korea. During this time, financial difficulties disrupted and prevented the Imperial Japanese forces from covering up the stream despite several attempts to do so.
After the Korean War (1950-1953), more people migrated into Seoul to make their living and settled down along the stream in shabby makeshift houses. The accompanying trash, sand, and waste, and deteriorating conditions resulted in an eyesore for the city. The stream was covered up with concrete over 20 years starting in 1958, and a 5.6 km-long (3.5 mi), 16 m-wide (52 ft) elevated highway was completed in 1976. The area became an example of successful industrialization and modernization of South Korea.
The urbanization rate, which was only 36% in 1960, was 88% in 2001. However, there was no consideration for water circulation in these urbanization projects. As the city developed, rainwater penetrated into the ground. However, the ground surface, which is the starting passage of water circulation to the river was blocked by asphalt or concrete. The river, which is a natural drainage passage is covered and used as a sewer, a road, and a parking lot. Groundwater content has decreased, but groundwater use is increasing. In addition, large-scale groundwater is pumped out to protect it from leakage of subway structure. As a result, the amount of groundwater recharge and the groundwater level rapidly decreased. In urban areas, water circulation has been broken. Also, floods increased due to the urban development in the upstream area were transferred to the downstream, making it difficult to cope with the flood damage in the downstream. As the soil was contaminated, groundwater also became polluted and a great number of groundwater became difficult to use.
The restoration of Cheonggyecheon was planned since the Joseon Dynasty. King Taejong repaired the rivers several times by spreading out the floor of the river which was in the natural state from 1406 to 1407, and building a dam in both sides. But this was not perfect, so the damage continued every time heavy rain came. Finally, in order to maintain the river, from January 15, 1412 to February 15, 52,800 people were put into the construction work. The main river was built with stone in both sides, and the bridges including Tonggyo and Hyeongjeonggyo were built. However, the rivers were located in the center of the city where many people live, and at the time when there was no sewage facility like today, all kinds of garbage and dirt had to flow into the Cheonggyecheon Stream.
King Sejong put a lot of effort into the maintenance of Jiecheon River and Secheon River. In particular, he dug a ditch in the back of the castle lined to the north and south of Jongno and connected the water directly to the downstream. This prevented the flood of the city centered by preventing the water of the Jincheon flooding all over the river. Sejong maintained the living river by accepting the latter argument among the conflicting claims to the former and the actual claims. Therefore, the Cheonggyecheon stream could be kept clean for the next 500 years.
In the 17th and 18th centuries, after suffering two devastations, many people flocked to the city and the population of Seoul increased so much that the sewage could not cope with it. Also, in order to overcome the cold due to the non-temperature phenomenon, people used the wood as a Bamboo firewood. Because of this, the mountains around the city became almost wilderness, and when it rained a little, the soil was washed down and filled up the stream. In 1725 when King Yeongjo was crowned, it was inevitable that the soil would accumulate and the bottom of the river would reach the same level as the plains. On February 18, 1760, the maintenance began. At that time, dredging the banks of the stream was divided into eight sections, from Songgigyo to the Yeongdogyo. They took out the soil which was piled up in the stream and recovered the depth and width of the stream as before. The damaged bridge was repaired, and the water in the palaces such as Gyeongbokgung, as well as the upper and tributaries were dredged to make the water well. The mobilized manpower was 200,000 people including 150,000 people of Hanseong citizenship and 50,000 people of employment, and 2,300 stones of rice were put in. In June 1773 King Yeongjo once again conducted airspace for river maintenance. The work was divided into three sections. Stacked stones on both sides of the levee and straightened up the meandering channel. In addition, they planted willow in both sides to prevent the levees from falling down when the heavy rain came. The restoration was completed in early August, two months after it started.
Since 1920s, when the period of Japanese colonial era, Japan has announced the plan to recover the Cheonggyecheon several times. In 1926, they announced plans to cover the Cheonggyecheon stream and build a 10,000-acre site. The plan was to cover the area from Gwangtonggyo to the main campus with reinforced concrete to secure a site of 10,000 square meters and to build residential, shopping mall and amusement facilities there. In 1935, they announced plans to build a road by covering the Cheonggyecheon stream and constructing a high-altitude railway over it. In 1939, an idea was laid to cover the Cheonggyecheon stream to make a motorway, and in 1940, the Cheonggyecheon stream was laid, and the subway was laid to rest and the subway was laid underneath. However, the plans failed due to financial problems, and the real closure was in 1937 in Mugyo-dong. In the case of Gwangtonggyo, the bridge line was placed, and the bridge was reinforced with concrete. Sewer pipes over 1m in diameter were buried in the light bridge. At that time, the Cheonggyecheon cave project was poorly supported by the Japanese colonial government, concentrated on infrastructures only in the southern part of the country. Hence, Cheonggyecheon and Bukchon were left behind. This construction can be interpreted that it was caused by the intention to make a kind of symbolic meaning by making difference between Japanese colonial government and Cheonggyecheon.
In July 2003, then-Seoul mayor, Lee Myung-bak initiated a project to remove the elevated highway and restore the stream. It was a major undertaking since the highway had to be removed and years of neglect and development had left the stream nearly dry. 120,000 tons of water were to be pumped in daily from the Han River, its tributaries, and groundwater from subway stations. There were safety problems due to the deteriorated concrete. Still, restoration of Cheonggyecheon was deemed important as it fit in with the movement to re-introduce nature to the city and to promote a more eco-friendly urban design. Other goals of the project were to restore the history and culture of the region, which had been lost for 30 years, and to revitalize Seoul's economy.
The Seoul Metropolitan Government established several organizations to oversee the successful restoration of Cheonggyecheon: the Cheonggyecheon Restoration Project Headquarters for the control of the whole project; the Citizen's Committee for Cheonggyecheon Restoration Project for the management of conflict between the Seoul Metropolitan Government and the union of merchants; and the Cheonggyecheon Restoration Research Corps for the establishment and review of the restoration plan.
To address the consequent traffic problem, the Cheonggyecheon Restoration Project Headquarters established traffic flow measures in the downtown section affected by the restoration work and coordinated changes in the downtown traffic system based on the research of the Cheonggyecheon Restoration Research Corps..
The restoration of two historic bridges, Gwangtonggyo and Supyogyo, was also a contentious issue, as several interest groups voiced opinions on how to restore historical and cultural sites and remains and whether to replace the bridges or not.
The Cheonggyecheon restoration project had the purpose of preserving the unique identity of the natural environment and the historic resources in the CBD of Seoul, and to reinforce the surrounding business area with information technology, international affairs and digital industries. The plan encouraged the return of the pedestrian-friendly road network connecting the stream with traditional resources: Bukchon, Daehangno, Jungdong, Namchon, and Donhwamungil. This network system, named the CCB (Cheonggyecheon Culture Belt), tried to build the cultural and environmental basis of the city.
Outline of restoration project
The project period is from 2003.7 to 2005.9. The spatial range is Cheonggyecheon (Taepyongno ~ Dongdaemun ~ Shinpyeong Bridge) and the surrounding area of 5.84km. The temporal range is the base year 2003 and the long term target 2013. The project cost was 349,423 million won as a result of estimating the construction cost for the restoration project of CHeonggyecheon before the start of construction. However, as of 2005, 386,739 million won was spent due to design changes and price change. During the construction period, public transportation center operation, designation of a traffic congestion area all over the city center, and transit traffic bypass treatment were applied, and the 6km construction section was divided to guarantee the construction of surrounding malls. 
Validity of restoration project
1. Change to a sustainable urban paradigm
In recent years, the international community has made efforts to universalize the new concept of environmentally sound and sustainable development through harmonization of development and conservation. The Cheonggyecheon Restoration Project is a city that focuses on Seoul as a development-oriented city, a city centered on a car, and a city that coexists with nature and people.
2. Recovery of ecological environment
In recent years, interest in the quality of life of citizens has been increasing, and environmentally friendly urban design has been universally continued in the world. The Cheonggyecheon Restoration Project is a project to restore clean water to the Cheonggyecheon Stream and restore the ecosystem to an eco-friendly city where Seoul is harmonized with nature.
3. Preventing Risk Factors of High-cost and Covered Structures
Cheonggyecheon is a product of the era of development that emphasized functionality and efficiency. In Cheonggyecheon and Cheonggye highway constructed in 1958, cement and rebar were already corroded after 3 · 40 years, and structural defects threatened the safety of the citizens.
O Amount of methane gas inside the Cheonggyecheon stream: 23 times (42ppm)
O Amount of nitrogen monoxide inside the Cheonggyecheon stream cover: 14 times (0.897ppm)
O Chenggu High Safety: All C grades, Part D or E grade
O Repair cost of Cheonggyecheon submerged structure: 2 billion won
O The USFK has been prohibited from entering Cheonggye high price since the mid-1990s
4. Restoration of History and Culture Space
The Cheonggyecheon Restoration Project is a project to recover the pride of the nation by restoring historical relics such as Guangtong Bridge, which is a representative cultural heritage in the Joseon Dynasty.
5. Balanced Regional Development
The Cheonggyecheon area around the Cheonggyecheon area was mostly occupied by buildings over 4 and 50 years old. Moreover, resolving the imbalance between Gangnam and Gangbuk areas is also a challenge for the balanced development of the city of Seoul.
The restoration of Cheonggyecheon can provide the conditions to reorganize the surrounding area into international financial, business-oriented, high-tech information and high-value-added business districts and raise international competitiveness. In addition, it is expected that the development of surrounding aged areas will become more active and the growth potential will increase, so that the Gangbuk area will be activated. As a result, the higher value added business as well as the balanced development of Seoul will be settled around the Cheonggyecheon area.
Assessment about Restoration
According to 'The Seoul Institute', about 7 out of 10(66.8%)citizens who participated in the survey of the progress in Cheonggyecheon Restoration Project gave positive grades. In addition, about 8 out of 10(77.6%) citizens gave positive response of future developments of Cheonggyecheon Stream. A survey conducted by 'The Institute of Seoul Studies' showed that 'Restoration of Cheonggyecheon Stream' was ranked 1st among the top 20 categories implemented in downtown Seoul from 1995 to 2010.
Cheonggye Stream restoration project influenced some foreign countries. Nagoya, Japan dispatched civil servants to receive know-how on restoration projects. In the United States, Harvard University published a book on the Cheonggye Stream restoration project and adopted it as a teaching material. In Los Angeles (LA), the old Cheonggyecheon restoration team in Seoul transferred the restoration know-how to the members of environmental organizations and LA councilors.
The Seoul Metropolitan Government has decided to restore the Cheonggyecheon with history and tradition by establishing a long-term plan until 2050. Until 2030, it will replace the ruins and improve water quality in the middle and downstream. Finally, by 2050, 4 more other streams would be connected to the Cheonggyecheon stream.
Change of species after Restoration
A total of 328 species, including plant species, emerged in 2006 from the restoration of Cheonggyecheon stream. A total of 446 species were collected in 2007 and 444 species in 2008. The overall flora has been repeated appear and disappear because of unstable environment at the beginning of the restoration. The plant species which need for beginning of the restoration showing a continuous increase pattern, also transplant species increased sharply and immediately after restoration. In 2006, 95 plant species and 233 transplant species were surveyed. Among the transplant species, 58 naturalized species of genotypes were investigated. Among them, there are three harmful species, Ambrosia artemisiifolia var. Elatior, Ambrosia trifida, and Eupatoriumrugosum. In 2007, the number of plant species and transplant species increased a lot compared to that of 2006, 134 species of plant species were found, and 312 kinds of transplant species were surveyed. The increase of plant species in 2007 was due to the opening of wild flower garden next to ecological custom, and the introduction of dietary plants for influx. In addition, it was found that the number of plant species transferred to the restoration river was increased due to the flood season and the increase in the number of visitors. The number of genotypes was 61, which is three more than that of the previous year. In particular, Solanum carolinense was added to the ecosystem for four species including three species in 2006. In 2008, the third year after the restoration, a total of 136 plant species were surveyed and 308 species were introduced. There were three kinds of ecosystem species for ecosystem, but no goby goby which appeared in 2007 was found because it was managed by artificially removing goby goby in the early stage. It can be seen that there is no marked increase in plant species and migratory species compared to 2007 and it shows that the species composition is gradually stabilized and that the structure of ecosystem is gradually stabilized. Due to the rapid nature of Cheonggyecheon stream, it is difficult to grow plants and submerged plants. Although it was limited, a lotus plant (Nymphoides peltata) was newly introduced centering on some water purification stations.
The stream was opened to the public in September 2005 and was lauded as a major success in urban renewal and beautification. However, there was considerable opposition from the previous mayoral administration of Goh Kun, which feared gentrification of the adjacent areas that housed many shops and small businesses in the machine trades.
Creating an environment with clean water and natural habitats was the most significant achievement of the project. Species of fish, birds, and insects have increased significantly as a result of the stream excavation. The stream helps to cool down the temperature on the nearby areas by 3.6 °C on average versus other parts of Seoul. The number of vehicles entering downtown Seoul has decreased by 2.3%, with an increasing number of users of buses (by 1.4%) and subways (by 4.3%: a daily average of 430,000 people) as a result of the demolition of the two heavily used roads. This has a positive influence by improving the atmospheric environment in the region.
The project attempted to promote the urban economy through amplifying urban infrastructure for a competitive city in the business and industrial area centered on the stream. The urban renewal project was the catalyst of revitalization in downtown Seoul. Cheonggyecheon became a centre for cultural and economic activities.
Cheonggyecheon restoration work brought balance to the areas south and north of the stream. During the modernization era, downtown Seoul was divided into two parts, north-south, based on their features and function. The restoration helped to join these parts to create a new urban structure connecting the cultural and environmental resources in northern and southern areas of the stream (Hwang n.d.), resulting in a balanced and sustainable development of northern and southern areas of the Han River.
Some Korean environmental organizations have criticized its high costs and lack of ecological and historical authenticity, calling it purely symbolic and not truly beneficial to the city's eco-environment. Instead of using the restoration as an instrument of urban development the environmental organizations have called for a gradual long-term ecological and historical recovery of the entire Cheonggyecheon stream basin and its ecological system.
The cost of managing Cheonggyecheon has been rising every year.
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The Cheonggye Stream east of Dongdaemun Market
Live entertainment on Cheonggye Stream near Dongdaemun Market