sustainability Article How Do Mega Projects Alter the City to Be More Sustainable? Spatial Changes Following the Seoul Cheonggyecheon Restoration Project in South Korea Chehyun Ryu 1,* and Youngsang Kwon 2,* 1 Department of Civil and Environmental Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, Korea 2 Department of Civil and Environmental Engineering, Integrated Research Institute of Construction and Environmental Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, Korea * Correspondence: [email protected] (C.R.); [email protected] (Y.K.); Tel.: +82-2-880-8200 (Y.K.) Academic Editor: Tan Yigitcanlar Received: 27 September 2016; Accepted: 9 November 2016; Published: 16 November 2016 Abstract: Urban megaprojects change the city in various ways over a long period of time. These changes may be very clear and calculable, but it is the changes that follow which are unpredictable and extensive. Especially in fast-changing cities like Seoul, Korea, projects like the Cheonggyecheon Restoration have massive effects on the surrounding environment. The purpose of this study is to analyze the spatial changes in the downtown area after the Cheonggycheon Restoration Project (2005). The economic; social, and physical effect and the outcome of the restoration project have been studied before the restoration, but the actual changes that occurred afterwards were understudied. Since subsequent spatial changes in the surrounding area occur over a long period, continuous observation on the physical effects should be made. Thus, unlike most studies that focus on the immediate before and after effect of the Cheonggycheon Restoration Project, this study focuses on the ten years of physical changes that followed the restoration. The study covers roughly fourteen large blocks, which were divided into seven categories based on current land use and the historical background of the city form. Physical changes of newly-built buildings, the number of renovations or building extensions, and socio-spatial changes, such as the rise and fall of urban industries, changes in building use, and overall changes in the characteristic of the blocks, were analyzed in accordance with their historical development of the city form. Commemorating the 10th anniversary of the Cheonggyecheon Restoration project, this study provides a better understanding of the overall effect of the project. Keywords: mega project; urban morphology; spatial changes; Cheonggyecheon; Seoul; urban regeneration 1. Introduction It is a widely held belief that cities must change, or they will wither and die. One of the key problems of urbanization is how to cope with these changes while retaining the structures constructed and maintained by previous generations [1–3]. Too often do we find places with years of urban history disappear as a result of thoughtless development. Especially in Asian countries that experienced urbanization in a short period of time, modernization is often followed by demolition of existing urban structures. Seoul is no exception. After the Korean War (1953), the priority was to rebuild the city damaged by the war and to escape extreme poverty [4–6]. Constructing tall concrete buildings was a symbol of national development, and modernizing the country’s capital (Seoul has 10 million residents, which is one-fifth of the national population [7]) was a priority. Preserving the traditional spatial structures established since 1394 became a priority only when the nation emerged from poverty and became stabilized in the 1990s. Sustainability 2016, 8, 1178; doi:10.3390/su8111178 www.mdpi.com/journal/sustainability Sustainability 2016, 8, 1178 2 of 16 Sustainability 2016, 8, 1178 2 of 17 traditional spatial structures established since 1394 became a priority only when the nation emerged from poverty and became stabilized in the 1990s. In thethe 1990s,1990s, concerns concerns were were raised raised among among the the City City Planning Planning Commission Commission and professionals and professionals about theabout thoughtless the thoughtless developments developments destroying destroying the city the form. city Thisform. was This especially was especially notable, notable, since thesince Seoul the CBDSeoul area CBD (the area capital (the capital of the Joseonof the Joseon Dynasty Dynasty was limited was limited to what to is what now theis now CBD the area, CBD and area, the and current the areacurrent of Seoularea of is Seoul 605 km is 2605) has km been2) has the been country’s the country’s capital capital for over for 600 over years 600 years [8–10 ][8–10] and is and filled is filled with meaningfulwith meaningful places places that portray that portray the lives the oflives previous of previous generations. generations. In 2000, In the2000, first the CBD first planCBD was plan made was tomade enhance to enhance global global competitiveness competitiveness by considering by consider theing different the different characteristics characteristics of the CBDof the area. CBD In area. this context,In this context, the restoration the restoration of Cheonggyecheon of Cheonggyech (Cheonggycheoneon (Cheonggycheon Project) was Project) an excellent was an example excellent of restoringexample of the restoring CBD area the [9 CBD,11–13 area]. [9,11–13]. The Cheonggyecheon Restoration Restoration Project Project holds holds a avery very significant significant meaning meaning in inSeoul, Seoul, Korea. Korea. It Itsymbolizes symbolizes a amajor major paradigm paradigm shif shiftt in in Seoul Seoul city city planning planning from from quantitative development to improving thethe amenity amenity and and livability livability of the of city. the The city. project The attracted project muchattracted national much and national international and attentioninternational and attention has been and attracting has been 20 millionattracting visitors 20 million and tourists visitors annually and tourists [3,14 annually–17]. [3,14–17]. 1.1. History of Cheonggyecheon One of the the reasons reasons why why the the Cheonggyecheon Cheonggyecheon Project Project was was highly highly spotlighted spotlighted was was because because of its of itshistorical historical value. value. When When King King Taejo Taejo founded founded the theJose Joseonon Dynasty Dynasty in 1392, in 1392, he established he established Hanyang Hanyang (the (thecurrent current Seoul Seoul CBD CBD area) area) as the as capital. the capital. In the In middle the middle of the of new the capital new capital flowed flowed Cheonggyecheon Cheonggyecheon from fromwest westto east, to east,dividing dividing Hanyang Hanyang into into two two (Figure (Figure 1).1 Since). Since the the stream stream was was the the main main water water source ofof the capital,capital, manymany attemptsattempts to to control control its its water water level level was was made made throughout throughout the the Joseon Joseon Dynasty. Dynasty. After After the Koreanthe Korean War War (1950–1953), (1950–1953), a massive a massive refugee refugee camp camp was was formed formed along along CheonggyecheonCheonggyecheon (Figure2 2),), and the sudden overpopulation caused the stream to turn into a sewersewer whichwhich beganbegan endangeringendangering public health. Subsequently, Subsequently, from from 1955 1955 to to 1961, 1961, Cheonggyecheon Cheonggyecheon was was covered covered by bybuilding building a road a road on ontop top of it of [18]. it [18 As]. Seoul As Seoul became became more more modernized modernized during during the 1960s, the 1960s, the number the number of cars of carsincreased, increased, and andan elevated an elevated highway highway (Samil (Samil Elevat Elevateded Bypass) Bypass) was was built built on on top top of of the the existing existing road covering Cheonggyecheon in 1976. At the time, the elevated highway was the symbol of modernization, and many modern buildings were constructedconstructed alongalong thethe highway.highway. Figure 1. Old map of Hanyang (Library of Congress). Figure 1. Old map of Hanyang (Library of Congress). In 1992, the Korean Society of Civil Engineering determined that the elevated highway was no longer safe to use, and the idea of restoring Cheonggyecheon was discussed among the academia and city planners [10,19,20]. Restoration of the ancient stream became a hot issue during the mayoral election of 2002 [21]. As the two main candidates took separate sides on the issue, the restoration project became a topic of national interest. While candidate Min-suk Kim opposed the idea, candidate Sustainability 2016, 8, 1178 3 of 17 In 1992, the Korean Society of Civil Engineering determined that the elevated highway was no longer safe to use, and the idea of restoring Cheonggyecheon was discussed among the academia and city planners [10,19,20]. Restoration of the ancient stream became a hot issue during the mayoral election of 2002 [21]. As the two main candidates took separate sides on the issue, the restoration Sustainability 2016, 8, 1178 3 of 16 project became a topic of national interest. While candidate Min-suk Kim opposed the idea, candidate Myung-bak Lee made the restoration project his top campaigncampaign priority [[20].20]. Following the election of candidate Lee in 2002 (74.6% of the respondents supported the restoration of Cheonggyecheon [21]), [21]), the Cheonggyecheon Restoration Project HeadquartersHeadquarters waswas established.established. Figure 2. Refugee camp along Cheonggyecheon (Seoul City History). Figure 2. Refugee camp along Cheonggyecheon