How clear, clean, pure. Warm, but not too hot, just out of its source deep inside the mountain. Next to it the little stream carrying «normal» cool water. As soon as they mix it can’t be distinguished any more, it will all be medium temperature water on its way to the sea.
I’m afraid it will become dirtier too. And more powerful. Maybe carrying boats, cargo? Until it reaches the sea – there again it will be a little nothing, a few drops in the ocean, invisible on its own, its origins unknown.