Rain City Initiative Proposed by Suwon City, Korea

Rain City Initiative Proposed by Suwon City, Korea Won Jeung Yeon* Mikyeong Kim** Mooyoung Han** *Suwon city, **Seoul National University 1. Introduction Korean people learned how to overcome the natural disasters caused by irregular rainfall trend, which results as the frequent flooding and drought, and geological condition, with their philosophy and technology. The priority of the sustainable city is water management, shown in a single character 洞 meaning village. The character combines characters meaning water( 水 ) and same ( 同 ), thus imply village people depend on same water: teaching village people why water should be conserved. This character also implies water status should remain the same even after the development. The reason for rainwater management is hidden in this single letter. For the purpose of scientific water management, the first rain depth measurement gauge was invented in 1441 by King Sejong the Great, and the rainfall data has been recorded through the nationwide rain gauge network. Many decentralized ponds and reservoirs were built throughout the country with rainwater management to encourage agriculture. Name of Suwon is derived characters meaning source of water; however, Suwon does not have a big river or dam thus always short of water. With the rapid industrialization, and city development, water source was contaminated and underground water and water sources were exhausted. It became clear Suwon faced a problem of securing the water source. Suwon city, literally the water origin, recently recognized the origin of water is Rain, and took initiative to make Rain City by every stakeholder, including City Mayor, City Council, Citizen group, Academic and Business sector. In this paper, the current regulatory activities and on-going projects, like Rainwater Showcase project in Suwon Sports Complex and Rainstreet Project in Gwanggyo Central Business District, the vision, and strategy of Suwon City will be presented. 2. The concept of the Raincity Raincity is a city that realizes the importance of rainwater and uses rainwater as a water source,

instead of wasting it. Raincity s citizens secure the water resource, minimize the unexpected rain damage and lower the energy use, thus benefit. Many creative and revolutionary rain businesses, like rainwater street, rainwater garden, rainwater museum, etc, are breaking through. Rainwater use policy will be made soon. Letting know of the rainwater s importance and making the international Cheukwoogi network for scientific measurement of the rainwater amount can solve many water problem. Achieve the Strategy for Climatic Change Adaptation Introduction to General City Government Politics & Administration by City Authorities Rain City Education & Promotion for Citizen Business Sector (Rainwater Industry) Academic Sector (Research Project) Suwon (the Origin of Water) = Rainwater Fig. 1 The Concept of Rain-city Initiative proposed by Suwon city 3. Regulatory activities and on-going projects 1) The regulatory activities Suwon city s Integral water management and basic regulation for realization of the Rain city was enacted and January 8 of 2009. The main contents of the management system are arranged in the table 1. Regulation states that, Suwon city advises and will support a part of expense for installing a grey water facility or/and rainwater facility for gardening water, toilet water, cleaning water, etc. in public place to be built, common buildings of land area more than 2000 m2, and total floor area more than 3000m2. The regulation contains the integration of the administration works for water management such as water service, drainage, stream, rainwater,

and ground water, systematically. The basic plan for integral water management and practical plan for individual part will be renewed every 10 years. Suwon city is leading the citizens and NGOs proactive participation for water management through subsidizing activities and research projects. Suwon s water cycle management regulation was created by members of the Suwon assembly on May 19, 2009 and is being processed for enactment. With the regulation, the institutional foundation will be found for water cycle management by rainwater and Suwon will carry out the detailed projects. The regulation contains the basic plan of establishment for water cycle management in every 10 years, installation guideline for operation of rainwater facility in various buildings like sports complex, gymnasium, public restroom, business building, house etc. and Suwon s financial support for installation of rainwater facilities and support for technology development. Table 1. The regulations for realization of the Rain city in Suwon Date Title Status Contents 2009.1.8 Suwon city s Integral water management s basic regulation 2009.5.19 Suwon city s water cycle regulation Enactment - advises to install a grey water facility or/and & rainwater facility in public building and common Enforcement buildings of land area more than 2000m2 and total floor area more than 3000m2 - supports a part of the expense for installation - the integration of the administration works for water management for water service, drainage, stream, rainwater, and ground water - induce the proactive participation of citizen s for water management Instance - contain the basic plan renewal of water cycle & management in every 10 years. Under - guideline for installation and operation of rainwater progress for facility in various buildings such as sports complex, enactment gymnasium, public restroom, business building, house and so on - subsidize the expense for installation of rainwater

facilities and support for technology development 2) Project 1: Suwon Sports Complex This project is designed for the rainwater facilities for rainwater retention, use and infiltration in the Suwon sports complex to prevent flood, improve water independency ratio, recharge the groundwater and offer citizens well-being and amenity (Figure 2). For the flood prevention, it targeted 50% decrement of peak flow and no discharge of 100 mm/event rainfall on the site through the rainwater retention, use, and infiltration. There are goals of 50% decrement of tap water use by Rainwater use and 0.5 cm rise of the ground water level by rainwater infiltration. About 50,000 citizens come to the sports complex every year. It is expected to offer more citizen friendly waterfront by applying rainwater management facilities.

Fig. 2 Design of rainwater facilities for Suwon sports complex 3) Project 2: Rain street project It is being processed a project for street space design of central business district (CBD) in the Kwangyo new town of Suwon to revitalize the town and construct sustainable urban space. The rain street project is a part of this project. Rainwater management was set as a paradigm of new town development which makes rainwater ponds in various areas around the city. Therefore, we are able to expect the effects that control urban drought and flood in a short time, and relieve heat island effect, recharge groundwater, preserve urban ecosystem, and secure sustainable water cycle in a long time. Rainwater acts as a axis of a physical space composition in the concrete for CBD street space, and it will accelerate and approach completion of rain city development by being connected with Rain city cluster of Suwon city

Fig. 3 The design of the Rain street 4. Vision of the Rain city Suwon 1) Improvement of the local water independency ratio by multi functional rainwater facility Suwon city is using the centralized system for water supply, which highly depends on water supply systemㅡlike other cities in Korea. Centralized water management system has problems caused by water supply processing which uses excessive amount of energy use, low system stability, little alternatives of water resource in local area out of reach, and so on. Rainwater usage is one of the sustainable water management strategies. Suwon s water source amount available for rainwater usage is 162.51 ton per year, maximum. If 70% of rainwater can be harvested and used, Suwon will reach its water independency ratio. So, if the goal is set, fit rainwater harvesting system can be constructed and used, water independency ratio will be met. Table 2. Theoretical rainwater volume according to improvement of LWIR in Suwon city Local water independence ratio (%) 10 20 30 40 50 100 Available rainwater quantity (million m3/year) - 13.2 27 40 53 119.2 Available rainwater quantity /Total rainwater(%) - 8 17 25 33 73

If the rainwater is used actively, Suwon s water independency ratio will be higher and its watercycle will be recovered by infusing the wasted rainwater. Also, by changing the efflux characteristic, the usage will prevent flooding by saving rainwater from reaching lower stream too fast. Rainwater management does not simply mean collecting water source by changing the reservoir system. Rainwater management system consists of collection and use system, disaster preventing reservoir system, and rainwater infusion system. By combining those systems, it maximizes the functions of each system thus set up multi-function rainwater management system. 2) Rain Culture s international guidance Korea s rainwater management system has been one of the top from the historical times. Suwon will make a leap as the city that guides the world with Rain Culture with this powerful method. To do so, Suwon has made a MOU contract with Seoul National University s Rainwater Research Center, and will seek for the specific executive strategy with the result gained from research. Suwon is on ICLEI enforcement committee and will establish international center for ICLEI rainwater management. Collaborations with international organizations like WWC, IWA, UNEP, UNESCAP, UNESCO, etc., Suwon will be renowned as the Rain City and spread the concept around the globe. 3) Raincity network construction Realizing the fact that, one of the easiest methods for adaptation to the climate change is decentralized rainwater management, Suwon is collaborating with Seoul National University s Rainwater Research Center and is spreading the concept of Rain City to other cities around the globe through ICLEI, WWC, IWA. By Suwon s Raincity advocacy, cities like Incheon, Daejeon, Gunsan, etc., are also declaring to be Rain City. From now on, we are anticipating that the Rain City s concept will be spread not just in Korea but other cities around the globe as the mean to confront climate change. 5. Conclusion 1) Suwon city is trying to build a fit water cycle system plan by building the Rain City, for the first time in the world. To support this vision, Suwon is making a few policies and projects to help the Rain City.

2) Rain city plan will not only help fix the water sufficiency level, but also the water cycle by the rainwater diffusion into ground. Also, it will help prevent flood, underwater foster, eco-cycle renaissance, etc., thus support sustainable growth. To make this happen, it will need the political and monetary supporters, and citizens engagement on international supportive level, and many detailed plan. 3) With Rain city plan, Suwon will nurture the rain industry with organizations like ICLEI, IWA, thus spread Rain city going abroad, improve the Suwon citizen s life style and financial situation, and adapt to changing climate, through marketing deduction, rainwater management policy and technique it will lead the low carbon green growth, and grow into internationally renowned city.