How to moat:
-dig 2 wide trench 1 deep
-dig outer edge 2 deep
-connect to water source
as soon as I get more hearthlings I plan to build an inner wall
then I will build a bridge leading enemies to turrets
Only con on this strategy is that we’re not yet capable of filling those holes up later in game. That’ll be implemented at some point surely but for now I’ll stick to destructable (costly) walls.
I think this is a pretty great idea. Trough history all city’s kept their walls up when expanding. They just build new ones a bit further. I think having a moat in the middle of your town as reminder of smaller times are pretty great for that immersion feeling
I believe you can. If your hearthlings build a floor and add slabs, that can act as a bridge. Of course, I’ve never tried that on a moat as narrow as OP suggests so you may well be right about moats of that size. But on a 4-wide moat, like the default you’d dig using the mining tool, you can make little floors and slabs.
Are you saying that 1 we can fill up the moat by building over it, or 2 that by construction and later destruction of a building over it the moat will be filled up by the engine?
My problem with 1 would be that the filled up line will not be grascolored, and I haven’t tried 2 yet but I don’t believe that’s how it works.
like quryx pointed at, cities would just build a new wall 
old walls and mounts either stay or are filled out and torn down.
likely to make room for a road.
but yes unless you use the color mod for slabs you wont get grass coloring again. (for now anyways)
with alpha 18 not only can you build a bridge, you can destroy said bridge and repeat
I think what I am going to do is test what width of bridges I need for different types of enemies and build defenses based on my findings
The varanus can cross a 1 wide bridge. Confirmed.
Will update as I see more enemies crossing the bridge.
Right now I believe all mobs are “1 width” to the a.i. I got a giant rock golem crossing a 1 width path too.
The thing about filling the moat works btw. You fill it with slabs, then order the destruction of it, the engine will fill it with grass again. (At least from one test I did it worked)
Yes, building a 1 wide block of “logs” going over the small trench can be destroyed and turned back into grass.
So what I am using them for at the moment is if I have too many injured soldiers I can destroy 1 block on those bridges and cut the town off from invaders for a day or two while they rest up- works the same way I would expect massive city gates to, whenever they get added.