I get absurd amounts of green water patches when generating new maps, even if only the "New Islands" mod is active. Is that intended behavior?

Vanilla has a bug: green water and blue water have the same noise for autoplacement. If you disable autoplacement by blue water, then you get green water on this place.

Thanks for the info -- that's too bad! I noticed that the transitions between land and green water look bad. That may have to do with "Nice landfill" which was loaded at that time. Aside from this, are there any functional differences between blue and green water?

The transition between land and water must be good, but between water and green water is always too ugly.