MikeFerrara:I was told by Doc (the owner) that when he baught the place it was a mud hole with no flow and no cave. He baught it because of a very old picture he saw of the place and he thought he might be able to restore it. Doc is like a mad scientist...inventor kind of guy. There had been a mill on the property and the dam stopped the flow and the cave filled in.
Doc started digging. At first they used scuba and buckets. As they dug, little by little the flow started to push through and things started to open up. The process continues and that's what those pipes are that run back to the grate.
So, yes it was altered by man. A man built a mill that plugged up the cave and made it non-existand. Then another man came along and tried to repair the damage.
Mike-
At some point in time the "roof" was also blasted out of the original cavern- I remember when there WAS a cavern there. By strict definition, there is no longer one there- at leastnot one that is sufficient for teaching purposes.