The answer to this question is not as straightforward as you think. But such a question comes up all then time when I evaluate whether a waterfall is worth seeing or not during my trip plannings. So that means I'd have to investigate interesting questions or issues such as the "waterfall" at Uluru in the center of Australia. I've also seen claims in the literature of the largest waterfalls in the world with megaflows in the tens of thousands of cubic meters per second discharge, but it falls merely 2m. Even the multitude of lacy cascades tumbling down mountainsides challenges us to make a distinction whether a particular waterfall should be recognized and called out or just something not all that remarkable.Well, in our minds, whether a waterfall counts or not depends on three main factors.
- Reliability of flow
- Height
- Slope
Reliability pertains to the frequency or longevity of the flow of a waterfall. The majority of falls around the world do not flow year round. So we have to ask, how long does it have to flow for it to be considered a legitimate waterfall? In high rainfall areas, if the flows are short lived, how frequently does it have to flow for it to count from being an ephemeral flash in the pan to something more substantial? The longevity aspect can be guessed or quantified by assessing the size of the drainage feeding the falls.
Height is pretty self-explanatory. How tall must a waterfall must be for it to count? Since waterfalls are aesthetically identifiable visually, it naturally has to be tall enough to be noticeable. So you can have a 3m (10ft) waterfall on a small stream and have it be a noticeable swimming hole and scenic landmark in a desert canyon. But you can also say that a 3m waterfall on a major river with a tremendous flow of over 1000 cubmic meters doesn't count because you can't tell if it's merely rapids or a waterfall.
Slope corresponds to a measure of how steep a waterfall's drop is. This is important because you could have a watercourse that loses a significant amount of elevation like say 100m, but if it's gradually sloping over 5 miles, you couldn't tell it's a real waterfall can you? Generally waterfalls with less than an obvious vertical slope (perhaps less than 30 degress or less) are generally defined to be cascades. But we tend to count cascades as waterfalls if you can look at them from afar and determine it looks like a waterfall (i.e. a strand of water streaking down a mountainside or cliff).
In any case, these are the thought processes involved in whether we determine we've seen or planned to see a waterfall. Certainly even these definitions differ depending on a person's own criteria. Moreover, there are other factors involved not previously mentioned (e.g. whether man-made or man-modified waterfalls count). Nonetheless, we've only addressed this question of waterfall legitimacy here so we don't flood the website with "waterfalls" we think the average person would ignore or wouldn't care about. But as stated earlier, there's some wiggle room for subjectivity and our opinions are certainly not gospel. So no matter what the definitions are or how they're interpreted, the point about waterfalls is that we should enjoy them for what they are and appreciate the fragile beauty of nature in the world around us.
