1 Liquids
With the 'Liquid' mode (Key F4) you can place waters on the map. The liquids can look different, if you choose different shader effects for them.
It's possible to create slanting waters with terrain editiing. If you want to create a river or sea which can be used by water vehicles, you should place the water on a flat surface. You'll also have to place virtual objects ('Shallow water' and 'Deep water').