Mooney Falls casscades past travertine. It is natural for the falls to change over time, as evidenced by the ancient crests lining Havasu and Mooney falls. The pools will regain their previous shapes, as the process repeats itself as it has been doing for millennia.
The water temperature of about 70 degrees remains relatively constant throughout the year. It's high mineral content and carbonate precipitate account for the pools and natural dams. The in-frequent floods repeatedly destroy many of these natural dams, but day by day and year by year they are constantly being reformed.