Bureau and Corporate Funded Body
Water overflowing the bank of Cheonggyecheon (Stream) during summer floods
Last year, I paid a visit to Yokohoma, Japan since I was looking for ways to reduce the damage caused by floods during summer. One thing that impressed me deeply was that the Japanese city had a municipal ordinance stipulating that all buildings be equipped with rainwater storage facilities. According to an official of the city, about 20% of the entire precipitation permeates into the soil to become underground water through such facility.
I thought a similar step could be taken at public facilities in Seoul first. Thus, Seoul City will install 920 rainwater gutters and an 850m-long rainwater permeation trench in 38 areas before the rainy season this year.
These facilities will facilitate the permeation of rainwater into the soil, thereby reducing damage caused by the overflow of rainwater and helping restore the natural condition of the soil. Seoul City plans to disseminate such guidelines for rainwater permeation facility installation to the autonomous districts.
The percentage of impermeability layer in the soil surface in Seoul, which stood at 7.8% in the 1960s, has increased to 48% by 2010. Downpour during summer is likely to cause flood in the lower areas, like what we experienced in Gwanghwamun and Gangnam intersection last summer. A large water drainage channel dug deep below the surface will be an easy solution, but it costs a lot of money. The method we are using this time is expected to go a long way in preventing flood damages at a reasonable cost. Ever since my inauguration as Seoul Mayor, I have discussed this matter with experts on several occasions. The rainy season is a long way off, but we must prepare well in advance.