Is the lusher green and treed area on the right bank not part of the enclosure? Methinks not as I also see a wall below it, apart from the contrast between the appearance of the grass in the two halves.
Its not the best of their enclosures- maybe for 'native wildlife' they didn't push the boat out so much, though the terrain would be pretty natural for them I guess.
Just because pedantry is amusing, I'm going to argue that this isn't a ha-ha. A ha-ha is meant to give the illusion that there is no barrier between lawn and pasture, or in a zoo, between public area and enclosure.
I don't think there is any intention to conceal the wall here, setting it into the slope is just the most convenient barrier they could make.
Indeed. Also, a ha-ha generally includes a wall anyway, as even indicated on the Wiki link above:
A ha-ha (or ha-ha wall) is a recessed landscape design element that creates a vertical barrier while preserving views. The design includes a turfed incline which slopes downward to a sharply vertical face, typically a masonry retaining wall.
