180,000 Tons of Water Pour Out Under Seoul's Subway Every Day

Water springs up daily beneath Seoul's subway lines. Over 180,000 tons of groundwater flow out across Seoul each day, and about seven-tenths of that comes from the subway system. If they don't pump it out, the tracks flood, but if they keep pumping, the soil between particles empties, causing the ground to subside – a true dilemma. What's even more regrettable is that this water, which is generally quite clean, was being dumped into the sewer system, incurring costs. According to Seoul City's calculations, this amounts to 35 billion won annually. So now, they're first diverting this water to maintain Cheonggyecheon Stream, and then reusing it for road cleaning, landscaping, firefighting, and even heating/cooling systems. It's like having an extra water pipe right under your feet.