I was going to say it's probably stylized and cut so much because no one can stay on for more than three seconds, haha.

http://vimeo.com/2080602

I think this is in the English Gardens in Munich. They have a man-made river running through the park. There's an area near a water input where waves form and surfers congregate.

The surf videos of the 90's are alive on this river.

This “river in a city” is the Eisbach in Munich, Germany: http://en.wikipedia.org/wiki/Eisbach