The government is working on a plan to expand road paving that absorbs rainwater to carriageways nationwide, according to reports on the 20th. With extreme downpours, defined as hourly totals of at least 50 millimeters and 90 millimeters over three hours, becoming more frequent, the aim is to reduce the risk of urban flooding.
The Ministry of Land, Infrastructure and Transport is recently working on a "roadmap to promote permeable block paving for carriageways." Permeable blocks are a paving method that allows rainwater to seep below the road through pores on the block surface or gaps between blocks. During heavy rain, it slows the speed at which water rushes into sewers all at once, reducing flood damage. Unlike standard asphalt paving, it absorbs rainwater and is also called a "sponge road."
Behind the Ministry of Land, Infrastructure and Transport (MOLIT)'s push to introduce permeable blocks is the increased risk of urban flooding due to the climate crisis. According to the Korea Meteorological Administration, the frequency of extreme downpours in Korea has risen about 2.4 times over the past 50 years. However, in central Seoul, the share of surfaces that are not permeable to water reaches 53%. Excluding forests, that figure soars to about 90%. In other words, a road system centered on asphalt worsens flood damage.
The Korea Institute of Civil Engineering and Building Technology (KICT) previously analyzed that, assuming a heavy rainfall scenario in Jongno District, Seoul, converting 20% of traffic areas to permeable blocks would increase the amount of rainwater that infiltrates into the ground or evaporates by 70% to 80% compared with current levels.
Currently, some local governments, including Sejong, Jincheon and Jeonju, have installed permeable blocks on carriageways. The Ministry of Land, Infrastructure and Transport (MOLIT) plans to evaluate items such as permeability performance, heat island mitigation and noise reduction through these cases. It will then pilot installations mainly in low-speed zones such as school zones and gradually expand the scope of installation.
After preparing the roadmap, the Ministry of Land, Infrastructure and Transport (MOLIT) plans to seek budget allocations next year with the Ministry of Planning and Budget for the pilot project. A MOLIT official said, "Permeability is a clear advantage, but we need to review which roads are suitable for its use," adding, "The pilot project could start as early as 2028."