Lifting bridge at Brig-Glis

Last Sunday I was in the Swiss town of Brig-Glis in the Rhone Valley. There is a tributary of the Rhone called the Saltina, which tends to flood often. The town suffered severe flooding in 1993 when sediment deposits under the bridge clogged the river channel. The water overflowed the banks, carrying with it a large amount of rubble. Two people were killed and there was a huge amount of damage. The authorities decided enough was enough.

The end result was this bridge, which is designed to lift automatically when the river level rises. The power to lift the 152-ton bridge comes from the river itself. As the water level rises, water flows into a tank. The weight of the tank of water lifts the bridge via a system of cables and pulleys.

View showing the bridge mechanism

There are metal slabs under the bridge, one each side as seen in the photo. When the bridge is raised, these slabs form a continuation of the concrete flood wall.

This bridge in Brig-Glis is the only bridge of its type in the world. What makes it unique is the fact that the power for lifting the bridge is provided by the flood water itself.