We do not have any whirling pools on our river Aare. It has too many dams and is too well trained to be exciting. However, on the borders of East Switzerland we have the Rheinfall. I was visiting my son a few years ago. He lives in a village near to the falls, so we paid them a visit and they are the daddy of the maelstrom strength, although if necessary they can be switched off for some peace and quiet, just like Niagara.
Funnily enough it does not seem to bother the fish that breed quite happily at the side of the falls filling the plates in the restaurants.