This is a temporary waterfall at the Vattenfall powerplants. Once a day they open the floodgates for about 5 minutes and the river Göta Älv flows through its old, natural riverbed. At this time, the waterfall transports 300.000 liters per second. The river connects lake Vänern and the Skagerrak. You can find some more info at Wikipedia.

The other 2 photos show a close-up and the area before the water comes.