Kaprun dam extension reaches 130 metres as concrete structure rises

The structural work on the expanded Limbergsperre dam at the Kaprun power plant complex in Salzburg’s Pinzgau region has been completed, ORF reported. The concrete dam was raised by almost 10 metres to 130 metres, increasing the capacity of the Wasserfallboden reservoir.

The expanded dam is scheduled for completion by the end of 2027. A topping-out ceremony for the project was held on Tuesday at the dam, located at an altitude of 1,700 metres. The expansion is expected to cost 66 million euros.

The Wasserfallboden reservoir will be able to hold 94 million cubic metres of water, up from 81 million. The raised dam must withstand a water load of 920,000 tonnes.

Roman Kohler, head of Verbund’s dams department, said the flood protection had been strengthened and the freeboard increased. He also said the dam’s arch construction helps carry the water load.

The additional volume corresponds to the annual drinking water demand of the city of Salzburg. The reservoir’s usable capacity will increase by 16 percent, while its storage capacity will rise by 30 gigawatt-hours to 190 gigawatt-hours. Kohler compared the additional storage to the capacity of around 500,000 to 600,000 car batteries.

Almost 25,000 tonnes of concrete were used to raise the Limbergsperre, roughly the amount needed to build an entire bridge over the Danube. Ice was added to a special concrete mixture, requiring 15 tonnes of ice to be produced on site each day.

In the coming months, workers will build a 1.5-metre-thick roadway and a parapet wall along the top of the dam.