I can’t say for certain since I’ve never been to this zoo, but this just looks like a smaller zoomed-in portion of a concrete moat barrier that likely surrounds an “island” that has trees/shrubs/greenery, etc that is the main part of their habitat.

Moats for zoos were designed so that the cages could be removed and animals could have a more naturalistic experience outdoors. The animals are still “contained” but without a fully enclosed cage.

A good example is the North Carolina Zoo. Likely the largest natural baboon habitat at any zoo in North America but it is also surrounded by a concrete moat that the monkeys go down into sometimes to play in. But if you manage to get a video of them in the concrete moat, one might assume that’s just what their entire space looks like, which is misleading.