RPG Insanity

Hello, Does anyone know how to pass this Water Palace? I've moving through 1st n 2nd and end up with a bunch of stairs blocked by a waterway (similar as the ones in the image blow) .. I cannot find a way to any other places in this palace.

 

Go back and you will see a floor stairs at close, there is a switch on the upper floor which will drain the water. The usual of water filled places. Drain water to advance.