I have discovered why Prophet's Rest is so generous with their water. The well at the edge of the compound is built directly on top of what the locals call a 'water vein' - an endless supply water bubbles up from beneath the earth.
It's existence is a minor miracle, though compared to what I saw in the starlit sanctuary, minor is the operative word. I suppose this ARK must be floating among the stars just as the Island was. What an extraordinary thought! I cannot fathom how such a thing is possible, but that remarkable metal must be at the heart of it. I am certain.