Was just on the Magic (which is Wonder's twin) on Deck 1, and our portholes were pretty high above the water, I'd say at least 8 feet. They also have really heavy-duty metal shutters that can be closed by
DCL staff, I assume should there be issues with water coming up that high, but it seems really unlikely. I was on a
Royal Caribbean ship, deck 2 (which is their lowest deck, equivalent to Deck 1 on DCL) and the waves were so bad I felt sure I was going to be thrown from my bed (seriously) but even in those crazy seas water was not coming up above our porthole.