[xJones]

15 metres (50 ft) to 25 metres (80 ft) deep and stretch four kilometres (2.5 miles).

The moat would only be 2.5 miles long, so apparently most of the tunnels are dug under that small an area. Hmmm, and they aren't dug deeper than 80 ft. max....

All right, dig that moat! And don't fill it with water, leave it dry and mine every square inch of the bottom and sides.

[SJackson]

The moat would only be 2.5 miles long, so apparently most of the tunnels are dug under that small an area. Hmmm, and they aren't dug deeper than 80 ft. max....

I'd assume it's only being considered in the Rafah area, where there are numerous building for the Gaza tunnel terminations. If they can build it 2.5, they can build it 12 without much more effort though.