How to use this to make a small lake?

[ChenQinz]

Like "Nettilling Lake" on google map , outside is ocean,inside is lake,use different color, Thank you.

[Verasl]

Currently doesnt have support for this, I have plans down the line to make the water more customizable and will keep in mind this idea, but again this is not meant to be a fully fledged water system.