How do you a waterfull on Roller Coaster Tycoon 3?

Answer 1

1. make a hole in the ground
2. fill it with water
3. make a hill or moutain next to it
4. put a hole in the top of the hill or mountain
5. make sure the edges of the mountain are small enough for water to go over
6. if they aren't, use the smooth tool and put it on 1 square and flatten the edges
7. click the waterfall tool
8. select both bits of water

now your waterfall should work