This is a set of three new enclosures (built 2015). I really liked the design here. Generally speaking, wombat enclosures are built by digging out a big pit, lining the whole thing in concrete or mesh, and then filling it back in. This stops the wombats digging out. But it also restricts the size of the enclosure somewhat.
Here the fence is simply metal poles driven into the ground 1.2m deep. It is comparitively cheap and effective, and means that the size of the enclosure is not really an issue. You can make it as large as you need. The tops of the poles come up a couple of feet to form the visitor barrier (the capped verticals which can be seen here).
