Water ripple question sounds kind of silly to me, although you probably have your good reason about it.
Intuitively speaking, those ripples can be explained by physics. Winds, movement of beings in water, etc. - outside influences. If you look at the water in a pool, you will see how smooth and calm it is, enabling your clear view of the bottom of the pool, because a pool (without people in it) has no outside influences.
You can look at a glass of water too.
So I don't understand your fascination about it.
But, randomness is a thing that easily creates obsession.
I don't have a slightest HINT on how can it work, if it exists in the very place. But what are the consequences if it doesn't exist? Everything happened as it must have happened, because there is a pattern. Our actions, creation of MD, this forum, this typing of mine, our thoughts... Everything would be logical, natural, and the only way of happening.
Meaning, someone with a huge database, so huge we can't realize, would be able to determine every event in the future as it must happen.
There wouldn't be free will. We think like this because we had to think like this.
That leads me to a conclusion that there should (a big should) be randomness. Otherwise, existence is pointless. Unless there's an outer universe. But that universe has to have randomness. Or again, an outer universe... x) Etc.