[DRG]

I assume you mean adding a water hex to a "normal" map and not adding a beach hex but your questions is very ambiguous. Do you mean the REPORTED terrain or what you see on the map?

You can take the beaches out and add things like rough terrain or swamp but if you, for example, add a single water hex to a map then click on the surrounding hexes with rice paddies the reported terrain will be fields ( it's a game quirk ) but it will still show beach. You can also surround a water hex with pavement and it will remove the appearance of beach. The best thing is to experiment to discover these things.

Don