Someone in Indonesia asked me about this. It is supposed to be from a university entrance exam. This is the question exactly as she presented it to me:
97. The splash of water at the base of a waterfall caused a mist of water in the air that often results in the formation of rainbows.
Pick one underlined phrase that might be incorrect.
Now, to state the obvious, there is a gross error in the sentence: the word "caused" should be "causes." But that's not one of the choices. Let's make that correction:
The splash of water at the base of a waterfall causes a mist of water in the air that often results in the formation of rainbows.
I personally feel that this sentence is perfectly correct.
Straining for what the quiz writer might have had in mind, I did come up with a theory, based on the precise definition of the word "waterfall" in oxforddictionaries.com and ahdictionary.com. My correspondent came up with a different and more likely theory, based on a web search that uncovered the original source of the quotation, in which one word was different from the exam version. I don't want to say more because I don't want to bias any responses.
I apologize for interfering in your discussion. Although my knowledge of English is only at the elementary level, but I'm 100% sure what should be: the foot of a waterfall
And, perhaps: a haze of water
I think "caused" is correct
(Part 2) My personal discomfort, like Susan's and Edwards, concerned "the base." Here, everything turns on whether the word "waterfall" includes just the liquid water itself, or whether it includes both the liquid water and the rock formation it falls over. The issue is that a base is a support, and the cascade of liquid water itself is unsupported--or, at any rate, is not supported by the plunge pool into which it falls! I noticed that oxforddictionaries.com's definition, "A cascade of water falling from a height, formed when a river or stream flows over a precipice or steep incline," seems to distinguish between the waterfall, which is the water, and the precipice, which is separate. Obviously the precipice has a base. Possibly one could say that the water does not. However, it isn't much of a stretch to expect people to read "the base of the waterfall" and understand "the base of the precipice of the waterfall!"
Anyway, I will give my correspondent the link to this discussion and say, unequivocally, that it's a bad question. The sentence presented in the exam is either perfect English, or it has a problem with word choice that is so subtle that not all native speakers see it or agree on what the problem is.
My personal guess is that the question was written by someone whose English was good, but not good enough to sense that "the splash of the water" could be the same kind of usage as "the babble of the stream" or "the whisper of the wind," and probably thought that by altering the word to "splash" they were creating a gross error.
Sorry to interfere)
I also didn't like "caused" at first. But you can interpret the sentence like this. There was a splash and it caused a mist that often results in ...., but it didn't (or maybe even did).
If I were to choose I would think about the base as Susan.
"a mist of water" seems like an unnecessary repetition.
It would sound better if you used a different word, something along the lines of: "a dispersion" of water.
