There are 6 sports I can think of that would readily adapt to these river waves. Surfing, river surfing, wake surfing, freestyle kayak, skateboarding, and snowboarding. I have done most of these sports and the similarities allow for quick adoption of the others as long as you are proficient at one of them. These are all balance sports and people like to watch athletes.
Everyone wants that perfect shaped wave and once they have it, they want it bigger.
Requires a big heavy boat with a big wake. Any flat relatively calm water can work for this. Its just like surfing a small fast wave. Boats are now being specialty built for this sport. As you can see by the sponsoring, there is big money at hand.
Lesser known because the waves are less common and less people ride them. But this is starting to change. Downtown Munich has the Eisbach. Home of the kick flip. People surf it year round and Red Bull hosts events there.
When comparing all of the balance sports they seam to be location driven. If you live at the beach surf is more readily available. If you live in the city grabbing a skateboard is quicker than driving to the beach. If you live in the mountains you might be a skier or a snow boarder. In each of these cases the sport that is convenient or close to home is the sport the athlete adapts to. I grew up on a lake and an hour from the beach. Waterskiing and surfing are what I learned when young. If river surfing is close to home people will adapt to it.
The Following communities have river waves and people come.