Capturing movement in water is a tricky business.
If you are too fast the water looks like frozen ice. Too slow and it looks like mist. Somewhere either side of these extremes there is a range of exposure times where the movement simply makes the water look blurred.
Then there is that sweet spot where like magic you can see the flow and feel the liquidity of the water's movement.
Photo: Robert Rath, ‘Day 699, Liquidity', 5s f/16 ISO160 15mm