It would be nice if the water placements required tiers to place down. For example requiring you to place Shallow water first, and then water would place on top of it, and deep water would place on top of it. Shallow water being the base of the normal water and the green water.

Hhhmm, this would potentially require some new placement collision mask trickery which may not be entirely compatible with other mods that do things with water like for instance boats and offshore oil platforms.

Nonetheless I'll look into this when I have some spare time.