On the right side of the water, which is the far side from the visitors' perspective, the fence is set into the forest several metres, but on the left there are large patches of forest within what I believe to be two enclosures.
It's hard to estimate the size of the elephants' area because of the shape, the water and forest area, and the lack of views to what could be a large off-show area, but certainly within the 5-10 acre ballpark, and potentially higher.
