Why is there a ferry here?

After finally making it to Chungju after my bus ordeal, I went with a group on a ferry ride/caving trip. The first half of the trip involved a 2 1/2 half ferry ride- on a reservoir. Yep, a reservoir. Only in Korea! When the ferry takes off, it looks like its going to travel 100 feet and run into the other side... the reservoir is long, though, so it is an actual journey.
Then came the caving trip. It's a regular cave, similar to other caves I've seen. Only difference is that there is no tour guide, and they apparently don't care about their caves as you can touch and handle the stalagmites all you want. Also, there is a souvenir shop in the middle of the cave- another "only in Korea" thing.
This weekend involved 10 different bus rides and almost 16 hours of bus riding. A little overkill- but it looks like my time in SoKo is short so I want to cram in as much as possible!