I love photographing waterfalls. You eyes can see a large range of lighting conditions including details in the shawdows on a bright day. Unfortunately your camera can’t see as much detail.
So if you exposure for the shawdows the other parts of the picture is washed out. If you exposure for the highlights it washes out details in the shawdows. So for photographing waterfalls overcast lighting is best.
It also allows you to use a slower shutter speed with gives the water that silky cotton candy effect. Since the shutter speed is so low its another reason to use a tripod.