It may look nice, but its not for a leo. Leopard geckos come from very dry areas of the world. Also, not sure what size water fall you are talking about, but you can also risk the leo drowing in it. If you are looking for decorations, buy some FAKE plants and get suction cups to hold them up.
I dont want to make a whole nother post, so Ill post it here:
How does that styrofoam or faux rocks thing work? The rocks and stuff look really cool and Id love it in my vivarium. Could someone give me links or instructions on making these? Also how I should paint it, etc. Thanks!