Cryzbl: There is a gear (some text should pop up if you swim near it) and you can rotate it through pressing R and the left mouse button. It raises the water level and then you can swim up to the place you want to go. 
Heh, thanks, strange though I can't remember that... I probably wasn't paying attention (although I usually do read every text the game gives to me).
It was more fun the way he was doing... btw, I did it that way myself at first too. : P but it still got me nowhere because you do have to use the gear for the crystal puzzle. 
lol, foiled again!!
You call that fun? I already thought it had to be optional since it's so hard and sometimes she just jump the opposite direction...
Cryzbl: yes the mysterious ledge a bit below it. No one has proof of making it to there yet. 1 person has claimed to make it by making the nature form boost jump from the other side of the water... but it must have been sheer luck to make it.
D:
Sheer luck indeed, all boosts I do (on purpose or not) I just get flung in the wrong direction...