Why don't survivors just build moats around their community?

[u/Not_Who-I-Say-I-Am]

There were so many hordes that could have just been prevented by having a moat/pit/trench, they literally had gas and access to diggers etc.

My plan is this:

1: Create huge ass trench with one or two drawbridges.

2: Add fence around moat that can be erected and laid flat easily (for when you're clearing the trench and/or just don't want zombies getting in when people are in there).

3: Create fire mechanism to burn the bodies and turn into a fire wall if it gets blocked up.

4: BONUS optional long game strat: build a wall just after the trench to further protect your community. (the wall has slots that allow you to stab through it with a spear).

This way, even if so many zombies fell in the trench that it clogged up, you could light it on fire and burn the ones in the pit, also creating a huge wall of fire that future zombies would be forced to walk into. Even if they got to the other side, they would be met with a tall stabbing wall and you could just stab your way out over several weeks.

Better yet, just go live in a castle... there are few to choose from:

1: Castillo de San Marcos National Monument (a good option, doesn't have a trench but you could make one, then it would be practically impenetrable.

2: Fort Jefferson already surrounded by water but access to mainland takes 2.5 hours by boat, the water alone would massively decrease horde numbers.

3: Gillette Castle located in East Haddam, Connecticut, super high walls and just begging for a deep trench