I know how to get waterfall. If you're coming from the right, to left, you need to use the first current, or the water that makes you go in one direction idk what it's called,of water you see. If you notice, there is a part where there are two seperate currents, one on top of the other, both going the same way (to the left). You need to take the top one, as high as you can take it. You should have dodged a trainer, and started going up. when you go up there should be like a square of water you can walk on with a pokeball in the center, that is waterfall. Hope this helps.