Making lakes in terrain editor

How do I make large bodies of water in the terrain editor, not rivers?

Also, if you could, I would greatly appreciate help here after this gets solved.

 

In the library of the editor there is something called waterblock. Not water plane that is an ocean.

 

http://www.beamng.com/threads/2764-...in-for-Beam-NG-(in-depth-guide-with-pictures)
I think it has a section on making an ocean.