An Underpass That Turns into a Horror Space When It Rains

Uncontrolled Traffic, Levee Collapse, and Underground Characteristics Cause Accidents
"Local Governments Must Preemptively Block Roads During Heavy Rain Warnings"

Underground facilities used by citizens become spaces of terror every time it rains. Underpasses and underground parking lots are facilities used daily by countless citizens. However, during heavy rain, water rapidly accumulates, leading to scenes of casualties.

Following the 2020 flooding at Choryang Underpass in Dong-gu, Busan, and last year's underground parking lot incident in Pohang, Gyeongbuk, on the 15th, a flooding accident occurred at Gungpyeong Underpass in Osong-eup, Heungdeok-gu, Cheongju, Chungbuk, resulting in casualties. As of 10 a.m. on the 17th, 13 cumulative deaths were confirmed at the flooded Osong underpass accident site.

On the day of the accident, at 4:10 a.m. on the 15th, a flood warning was issued for the nearby Miho River, and by 6:30 a.m., the water level had reached a critical level higher than the warning threshold. Accordingly, the Geumgang Flood Control Office informed the local district office that traffic control was necessary, but no traffic control was implemented.

Drainage work continues in the early morning of the 17th at Gungpyeong 2 Underpass in Osong-eup, Cheongju-si, Chungbuk, which was flooded due to the collapse of the Miho Stream embankment. [Image source=Yonhap News]

Eventually, around 8:40 a.m., a temporary embankment near Mihocheon Bridge collapsed, and river water suddenly poured into the underpass. In the case of express bus number 747, where five deceased, including the bus driver, were found, the bus had rerouted into this underpass due to the heavy rain and met with the accident.

It has been pointed out that if the administrative authorities had established guidance or systems to block entry into the underpass, the tragedy could have been prevented. The Osong underpass was classified as a Grade 3 hazardous underpass by the Ministry of the Interior and Safety and was supposed to be controlled during heavy rain warnings.

Professor Jung Chang-sam of the Department of Smart Construction and Disaster Prevention at Induk University said in an MBC radio interview that "Looking at the budget for the end of this year and next year, a pre-blocking system was planned for the underpass, indicating that there was some awareness that flooding could occur." He added, "Since there was embankment construction nearby and a heavy rain warning was issued for the Miho River, it is regrettable that the local government did not proactively implement pre-blocking."

This year, a system was scheduled to be installed at the Osong underpass that would automatically detect when a certain water level was reached and block vehicle entry. However, during this heavy rain before installation, it is criticized that the administrative authorities should have controlled vehicle access.

[Image source=Yonhap News]

Another cause of this disaster was the collapse of a temporary embankment on a nearby river. Professor Ham Eun-gu of the Department of Fire and Disaster Safety at Korea Open Cyber University explained on SBS radio, "The usual flooding mechanism involves rainwater from nearby watersheds flowing into the underpass, but in this case, the embankment collapsed, causing an unprecedented inflow of river water." He added, "The watershed area and the volume of water rushing in are completely different from other underpass flooding cases."

Professor Jung Chang-sam pointed out, "The most important cause of this disaster was the temporary embankment." He explained, "For the Mihocheon Bridge construction, part of the embankment was slightly demolished, and a temporary embankment was built using sandbags or similar materials. Building a temporary embankment before the flood season is extremely dangerous."

Professor Jung added, "This can be thoroughly regarded as a man-made disaster. Reinforcement work should be done before the flood season, and the construction site should always be monitored during heavy rain, but it is unfortunate that the most critical river construction site was not properly managed."

The tragedy in an underground parking lot of an apartment in Pohang, Gyeongbuk, during Typhoon Hinnamnor last September also occurred due to the flooding of a nearby tributary. Heavy rain of about 100 mm per hour caused the nearby Naengcheon stream to overflow, and the water quickly flowed into the underground parking lot. Seven residents who went out to move their cars following the management office's announcement lost their lives.

Additionally, the characteristic of the underpass being lower than the surrounding area, making it prone to water accumulation, greatly exacerbated the accident. Professor Ham Eun-gu explained, "Because the underpass is lower than the surrounding area, it acts as a kind of stormwater drainage basin, causing water to rise rapidly in about three minutes." During the July 2020 disaster at the Choryang No. 1 underpass in Dong-gu, Busan, heavy rain of up to 80 mm per hour flooded the underpass, resulting in the deaths of three citizens.

This content was produced with the assistance of AI translation services.