Extreme Downpours Threaten Urban Safety; Disaster Preparedness Urgent

'Extreme downpours,' unpredictable due to climate change, are threatening urban safety.

A review of flood control measures for Busan's rivers ahead of the main rainy season revealed concerns that current systems may struggle to cope with the rapid increase in danger posed by torrential rain exceeding 40 millimeters per hour. In one instance, a riverside promenade in Busan was submerged within seven minutes and two citizens walking there were swept away and died during a downpour exceeding 40 millimeters per hour.

Frequent flooding in Busan's rivers is also linked to the complexity of managing them, as they are connected to the sea. Twenty-five of Busan's 49 rivers are 'tidal rivers,' where water levels rise along with the tide. When high tide coincides with rainfall, river levels rise even faster, increasing the risk of flooding in low-lying areas.

A professor from Busan National University's Green Land and Water Management Research Institute explained that urbanization is increasing flood volumes, and the increased use of riverbanks and parks heightens flood management risks.

To prevent loss of life, the Busan Metropolitan City has installed over 410 barrier gates at 512 entry points to urban rivers. However, approximately 20% of these operate manually, requiring staff to be dispatched to the site each time it rains to close them, posing an operational challenge.

As short, intense 'extreme downpours' become more frequent due to climate change, an urban river safety management system that closely reflects flood risk is needed.