I have read hundreds of landscape photography magazines and dozens of books on landscape photography. And I have visited the websites of many of the top landscape photographers.
There are basically two ways to shoot waterfalls: slow or fast.
Slow can be really long shutter speeds of 1-2 seconds or more which make the water extremely soft or ethereal. Slow can also use faster shutter speeds in the 1/15-1/2 range which, depending on the speed of the water, gives it some texture yet still blurring it some.
Fast will completely freeze the water with shutter speeds in the 1/500-1/2000 range.
I see very few frames using a fast approach. In part because the best times to shoot are usually at or around sunrise or sunset.
I did some additional research last night because someone made a comment to me that points are deducted for slow waterfall shots in photography competitions. I reviewed dozens of criteria from Kodak to National Geographic competitions as well as other leading photography competitions and I could not find any reference to losing points for slow waterfall shots.
In fact, virtually all of the winning shots of waterfalls that I found used a slow shutter approach.
This image, from Tim Fitzharris, is indicative of the most common approach to shooting water. My attempt from the same region, Great Smoky Mountains, is below. If it is good enough for Tim, then it is good enough for me. You can select from his stock photography here.