You can only dig down (or build up) 8 meters. If you can't get down to the water table in 8 meters then the moat will be dry.

I have used just a deep trench before when high, even in the Mountains, it works just the same keeps nasties away from your Base or whatever you have there. Does not need water in it, although that is useful near shore as you can always park you boat in it. I generally have my main base near the water.

my plan was to build a harbour so I wanted to dig out an area close to the shore and once done building it to fill it with water

Originally posted by Lethian:

my plan was to build a harbour so I wanted to dig out an area close to the shore and once done building it to fill it with water

Not really how it works. You can dig down deep enough to hit water (if within 8m) but you're not going to have a "break the dam" moment where you delete a wall and water comes rushing in. There either is water at a certain height or there isn't. It doesn't flow.

damn i was looking forward to the "dam breaking" moment

thats ;'how to' drain tar pools in the plains , you can fill a moat yes if you can dig down to sea level , up on a hill i dont think you can dig down that far

ok nice thanks alot gonna give it a try