Please, can anyone give me a strategy(or a way) to complete 'Treasure Island'?
I can't put the coasters in the water as I want the waterfalls to stay where they are. Please?

If you cant put the coasters in the water, I guess you try getting rid of the water.

There is auctally a way to build coasters on water
Pick the type of roller coaster you wish and put it in the correct position.
Hold down shift and moove the station piece up one part.
Left click on the station and continue building