The structure of the falls remains intact and dry, as the channel has changed course and water no longer flows here. Calcium carbonate adheres to rocks, tree branches, and debris - building up over time to create these instersting structures. Given the amount of water that flows and the concentration of the minerals, this happens blindingly fast in geological terms. In comparison, an underground structure takes centuries to build even close to the size of the formations along Havasu Creek.
Remembering an Oasis
This is an excerpt from a post by a student who traveled here in 2008, just before the flood:
"I described it as "a little slice of amazon dropped in the middle of a barren canyon. It is surrounded by jungle-like trees and plants and can be climbed. My class climbed up the falls and through the travertine pools. There are many falls and ponds up there in the forest. At the top, there is a wide cave-like rock structure that is covered in ferns and mosses that was a perfect photo-op. there is water falling from over the top and it is nice to sit on the other side where it's dry.
"What was amazing is when we got to the edge of the top of the main falls and looked out, we were surrounded by a thriving forest, covered by water, but we looked beyond and saw the canyon wall ahead of us, just rocks, dust and sand. The two sound like they could never go together, that is why it was amazing."- Deveaux, Los Angeles