Where did the water in Changdeokgung Palace's ponds come from?

Behind Changdeokgung Palace is an entire mountain valley. When heavy rain falls, the water from the valley pours down all at once, and below it were the royal residences. If a stream was dug straight, the water current would become too strong, and if it didn't rain, the garden would dry up completely. Therefore, instead of letting the water flow away, the rear garden retains it in stages, like stairs. Spring water fills Aeryeonji and Buyongji in sequence, and the overflow spills over the walls and flows into Chundangji in Changgyeonggung Palace. King Injo even carved a water channel into a rock, which is now known as Okryucheon.