Questions that arise from Zombieland

[Brian]

I've changed my plan... We're going to get an island. Like Mackinac Island and take refuge there. Those fuckers can't swim right?

They can't swim, but they can walk along the ocean floor. Zombies don't breath.

FUCK!! So how's a moat supposed to help then?? And I was thinking the Great Lakes, so would fresh water vs salt have any significance?

The moat will have vertical walls......Zombies can't climb, remember?