Trying to add an island to a map, it keeps going under water no matter how high it is

[Mikhail_CA]

The sea level is set to 40, but regardless of how high I set the level of an island, eventually water creeps up and envelops it. I'm sure I am missing something simple but I can't figure it out!

Thanks

 

[Mr Maison]

Are you using a water spawn or the default sea? I don't think the sea is supposed to rise.