On the 14th at Nowon Station on Seoul Subway Line 4. The station floor was soaked as rainwater poured in without letup. Employees hurried to sweep out the water with squeegees. It was found that foreign matter clogged the drainage tank near the platform roof, causing the rainwater to overflow.
But residents said this "happens every monsoon season." A person surnamed Kim, 34, who lives in Nowon District, Seoul, said, "Every year, rain leaks into the station," and added, "I'm worried that older adults or children could slip and get hurt."
This year, too, leak reports are piling up at ground-level stations across the Seoul subway. On the 21st, according to Seoul Metro, 54 leak reports were filed from on the 1st of last month through the 16th of this month at 14 of the 25 ground-level stations on Lines 2, 3, 4, and 7, or 56%. In other words, it rained into half of the ground-level stations.
Leak reports were concentrated on Line 4. Bulaemsan Station had the most with 12, followed by Chang-dong Station with 5 and Nowon Station with 4. Line 2's Seongsu Station also logged 7. The fact that many stations are aging facilities roughly 40 years since opening appears to have played a role.
On Lines 1 and Gyeongui-Jungang, the Suin-Bundang Line, and others managed by Korea Railroad Corporation (KORAIL), 21 leaks occurred at 18 stations during the same period. On Line 1, rainwater leaked twice each at Gaebong Station and Oryu-dong Station.
A main reason leaks recur every monsoon season is the aging of stations. A KORAIL official said, "As concrete repeats drying and shrinkage over a long period, gaps form at joints in platform structures, and water seeps in through these areas."
The structural characteristics of ground-level stations are also a factor. A Seoul Metro official said, "There are many aging stations, and some have height differences in the ceiling for ventilation, which inevitably creates structural gaps."
Experts note that leaks should not be viewed only as a minor inconvenience for riders. If water seeps into structures for a long time, rebar can corrode and concrete can crack or spall, potentially leading to safety issues.
Lee Eun-hyeong, a research fellow at the Korea Research Institute for Construction Policy, said, "If leaks are left unattended, the water that has seeped in can rust the rebar and cause separation between the concrete and rebar," and added, "Regular inspections and timely repairs of damaged areas are necessary."
Seoul Metro and KORAIL said they will step up monsoon-season patrol inspections of stations and carry out waterproofing and repair work focusing on locations where leaks are confirmed.