From an aesthetic point of view waterfalls are very appealing. They are my favorite fluid flow visual and sound. This particular video shows the cascading water hitting the rocks and surface water at the bottom of the fall. The falling water is a little out of focus because of the focus on the surface water. There is a direct boundary between the surface and cascading water that I feel encapsulates the essence of a waterfall. From a scientific point of view the water is falling with a lot of kinetic energy that when it hits the bottom of the fall, the change in momentum is vast which causes some of the water to go deep into the surface water and the rest of the water to ricochet up and clump up. I believe this causes cavitation which is why there are so many water bubbles on the surface in focus. This causes the water to become turbulent as it continues on its path.
Credits:
Christopher Michael Dortch, “Slow motion closeup of water crashing at the bottom of a waterfall.”, Jan 21, 2017: