At first it seemed like you can't remove deep water, but the trick to it is to build sand or rocky terrain next to it and then it fills it in, then you can change it to something else.

I like this mod, makes the game way more enjoyable as now I don't have to play the absurd dookie micro management game.

Found it, I had to active the mod first.

Where is the mod menu?

just go to the mod menu, select the desired soil and apply it on the surface, it is necessary to load the game to set the new values.

how to use this mode ?

That sounds good.