STORY: The city's development meant increased pavement and impermeable surfaces, leading to higher runoff and more flooding. More than 50% of Seoul's land areas are impermeable, with the figure much higher in the affluent Gangnam district with wide boulevards and office buildings, experts said.
Warmer weather increases moisture levels in the air, leading to more intense rainfall. So while there has been little change in the annual precipitation over the past four decades, the frequency of heavy rains in Seoul has increased by 27% since the 2000s, according to a 2021 report by the Seoul Institute.
In the wake of the downpour, Seoul Mayor Oh Se-hoon announced on Wednesday (August 10) the city would spend 1.5 trillion won ($1.15 billion) in the next decade to build six massive underground tunnels to store and release rainwater to prevent flooding.