Seoul to Samcheok, to Dogye. From Dogye take a taxi, and ask for "Eekey Pokepoe". The cab will take you to a small hamlet, where you have to walk 2 hours up and down a mountain.
Very out of the way stream in the Taebeak Mountain range in South Korea. Happened to come across someone's picture of it, and tried to find it on the internet, only to find that it's in my backyard (so to speak).