Who needs the sea? "Open river surfing"

By now you should know that my girlfriend is half German an therefore I visit Munich (south of Germany) every once in a while. A few summers back I witnessed the following:

Just outside the “Haus der Kunst” museum, sits a canal who's wildly gushing rapids have created the cities underground surfing spot de jour. The rapids supply local surfing buffs with ample waves, keeping their surfing skills sharp throughout the winter. It seems its one man at a time at this surfing hole, so future enthusiasts need to join the queue. Unlike the Aussies, these German surfers need not worry about sharks.