Best way to simulate an outside underwater area?

[Vale]

I dont know if anyone has really looked into that a lot yet, but I could be wrong. Keep in mind the game released a short time ago and that the beginners and experienced modders alike have to do a lot of research. Open the map up in the level editor and look the settings/exterior over. There will probably be a guide on this relatively soon, so if you dont find your answer be patient.