The barrage is designed to keep the water level upstream at a constant level - roughly equivalent to high spring tides.
It consists of movable gates with a navigation lock, a fish pass and white water canoe slalom course and has a road running over the top.
The 160m long main (road) bridge has eight 17.5m spans.
At each end of the four river spans, the road crosses the roof of the barrage pavilion and then an approach bridge with two identical 17.5m spans.
The arches are constructed from welded tubular steel and have a rise of 5m, which gives a clearance to the navigation channel and service roads.
NCN 1 runs across the Barrage on the low level foot / cycle bridge as seen in the photo.