Gov’t must revise flood protection manual

The record-setting rainfall brought by Typhoon Hinnamnor flooded underground parking lot of apartment buildings in the city of Pohang, North Gyeongsang Province, leaving eight dead. The victims had gone down to an underground car park to move their cars upon announcement of the apartment’s management office and got trapped by the incoming torrents. An elderly couple married for 40 years were found dead together; a mother in her 50s was miraculously rescued, but her 14-year-old son died.

Casualties by floods occurred in Seoul just a month ago, in an underground parking lot of a building in Seocho-gu inundated by heavy rains. These flood deaths highlight the vulnerability of underground spaces to flooding. Once water flows in, underground areas are quickly inundated owing to high floodwater velocity. The underground car park in an apartment building in Pohang was inundated in less than 10 minutes. When the spaces are filled to knee-height, walking can become extremely difficult, and doors will not open owing to the water pressure, which makes evacuation impossible. Typhoon Chaba in 2016 left a casualty in an underground car park in Ulsan; six people were isolated in an underground car park of a nursing hospital and hotel due to heavy rains in 2020 who were later rescued.

Compared to the hazards of flooding and inundation, the level of preparedness is low. When heavy rain is forecasted, cars must be pulled out from underground parking lots before rain starts to fall, and once the rain starts to pour, one must keep away from underground areas. However, the apartment’s management office is reported to have made an announcement even after the underground car park was partially submerged. This is owing to a vaguely worded flood manual directing the management office to make an announcement to move cars “when there is an inundation risk.” The guidelines prepared by the government in 2017 state that stop gates and rainwater drainage pumps need to be installed in underground areas. However, this only applies to frequently flooded areas and does not retroactively apply to underground spaces of an old buildings like the apartment in Pohang where casualties were reported.

Underground parking lots in recently constructed buildings are built deep underground to secure parking spaces, which are prone to heavy rainfall over 100 millimeters per hour that has become more frequented by climate change. The government and local governments should revise outdated flood protection manuals and distribute them and expedite installation of sewer and drainage facilities in underground car parks in large-sized buildings. Since the tragic accident in Pohang is partly attributable to the sudden overflowing of rivers, safety check of rivers and streams nationwide must be conducted. The National Weather Service predicts that another autumn typhoon is likely to impact the Korean Peninsula.