[Norfleet]

THe ability to cast a summon spell underwater is only tenuously related whether or not the unit is capable of underwater survival. In theory, it's possible that a summon spell could summon a unit incapable of surviving, in which case it would drown. In practice, however, all spells that are known to create such units currently are not permissible underwater. However, there ARE summoning spells which summon units perfectly capable of underwater survival as an innate ability, that nonetheless cannot be cast underwater.