신비한사전

This is Chundangji, a large pond deep within Changgyeonggung Palace. However, this spot was originally a rice paddy where the king himself would demonstrate rice planting. They placed a paddy field, not a pond, on the lowest ground of the palace where water naturally gathered. This paddy field was dug and turned into a large pond in 1909 when the Japanese colonial government transformed Changgyeonggung Palace into a recreational facility. Even when the palace was restored in 1983, the paddy field did not return. Still, the water flows over the wall of Changdeokgung Palace to fill this pond to this day...

Did you know that 92 million tons of trash are buried right under the silver grass fields of Sangam-dong's Sky Park in Seoul? The waste Seoul dumped over 15 years has solidified into two mountains, each 98 meters high, and there was no way to remove it. They covered it with soil, but then methane gas built up, causing fires to break out all over the mountains. So, what Seoul City chose wasn't to eliminate it, but to contain it and extract its resources. They built containment walls around the perimeter and installed 106 gas pipes to extract methane, which is now being used to heat the World Cup Stadium. Even planting silver grass was a calculated move, as its shallow roots wouldn't penetrate the waterproof layer, meaning every aspect of the landscape was considered...

Even when torrential rain pours down, water doesn't pool on the stone courtyard in front of Gyeongbok Palace's Geunjeongjeon Hall. This is despite water flowing directly from Baegaksan Mountain behind the palace. If they blocked it with walls, the water inside would be trapped, turning the entire palace into a basin, and if they tried to channel it out in one stream, the water's force would erode the floor stones. So, Joseon chose to break it down into smaller streams and let it flow slowly. They created separate drainage channels for each area, with sumps called 'jipsujeong' to settle dirt and fallen leaves before the clear water was directed into underground stone waterways. What's most surprising is that they didn't excavate the land but utilized its original slope to guide the water's path. [][]

Seoul has six plants that pump up water from the Han River and turn it into tap water. They produce 3.8 million tons a day, enough for Seoul's 10 million residents and even supplying four cities in Gyeonggi Province. How does river water, which looks like muddy water, actually become drinkable? The key was not to force out small particles, but to clump them together, make them bigger, and then let them settle. However, the smell of summer algal blooms dissolves in the water and can't be filtered by sand. So, they added two more stages using ozone and charcoal.......

They are still digging a tunnel 40 meters underground in Gwanghwamun, Seoul. Once completed, this 2.3km long tunnel will hold 122,000 tons of rainwater. This method was devised because the area under Gwanghwamun is already packed with subways, electrical lines, communication cables, and water pipes. It's a proven method. The Sinwol Rainwater Tunnel, completed in 2020, successfully managed the record-breaking downpours in 2022. The Gwanghwamun Tunnel is currently under construction with a target completion date of 2030. [][][]