Hi David
I get this question ask a lot. People tell me, the light was yellow, the light was green or it was red or whatever and that is the way it was, I remember it well. (But memories can trick you)
Have you ever noticed the over saturated TV colours in hotels and other public places? People love strong colours.
Now the answer.
Firstly believe it or not; 40 years in photography and fine art printing (some 10 years.)
Secondly; Software.
1) When you look at your photograph that I identified as being to blue, what do you see. You see water that runs over a lip and as it does so it picks up air. Air makes the water appear lighter in colour and if it is churned up enough into a fine spray no matter what the water colour will actually always appear white. (if there is enough air) and as it hits the bottom it becomes even lighter and often you see white foam appearing. To make the water or the bottom splashes in your picture render as blue it would have to be "body tinted" and I think this would not be the case unless it was heavily polluted with something. You would have to shine a very strong blue theater light onto the scene to get that sort of reflection on that angled tree trunk for example.
There is a phenomenon called the "Blue Hour"
Blue Hour and Night Photography | How to learn tutorials | bluehoursite.com but to judge by the sky you were not in it. When next time you revisit the scene take particular notice of this.
2) Second part of the answer is software related. I have specialized software that reliably detects colour pollution and removes it. I have no understanding how the software actually does this but I believe in simple terms there is an algorithm which looks for a uniform colour value that appears as a component in addition to the known colour values as the sensor has recorded them, identifies this value and removes it from the picture. There are degrees of accuracy and further adjustments can/must be made. See part 1) But surprisingly casts can be removed accurately and the result ... well if you don't like... you can always go back to the original.
Greetings