Chance always succeeded, simply because he didn't know he could fail. His words were interpreted in the best way, he always found his luck, he always hit the right note with people. I see the pond as fairly shallow in most places, with a drop off near where Chance walks (which is why the umbrella goes so deep). Where chance walks, the pond is somewhat shallow, but with rocks just barely under the surface. A normal person might try to walk across on the rocks, but would never succeed, because they are slippery, or they'd fall into the deeper area, etc., just as what normally happens in life. But for Chance, who always seems to get it just right - he doesn't even think about it - he just walks across ON THE ROCKS JUST UNDER THE SURFACE. In a sense, this does not deny the Jesus allegory, but maintains a realism that pervades the rest of the movie. The pond CAN be walked across on the surface, but only by Chance, because he can do so without thinking about it.

It looked to me like Chance is surprised to be able to walk on water - thats why he checks the depth to double check.

So, I believe the scene compares Chance to religious figures - some of whom may have come by their stature by accident, because of people who hear what they want to hear.

Chance’s life was not only a commentary on the modern life but I thought it was also a comparison to the life of Jesus. Now I picked up on this well before the walking on water scene. Chance was just an idiot gardener stating obvious facts at unusual times, these were then taken as parables and interpreted to fit the listeners perceptions and expectations. Uncomprehending silence was taken as wisdom; dim-witted non-sequiturs taken as gospel. The miracles explained away as simple luck and, in the case of walking on water, simply being to stupid (or innocent, take your pick) to know that you can’t do that. Take it for what it’s worth but I think the film makers were offering an alternative as to what really happened and who Jesus (or Buddha, if you like) was