Kolnbrein Dam

The Kölnbreinsperre was built between 1971 and 1979 at the head of the Maltatal at about nineteen hundred metres, a double-curvature arch dam two hundred metres high and around six hundred and twenty-six long at the crown, which makes it the tallest dam in Austria; it holds a reservoir feeding the Malta hydro scheme, one of the largest pumped-storage systems in the country. Cracking appeared in the dam from 1977, while the reservoir was first being filled, and after years of repairs a substantial remedial structure was built at the base, which is visible and which the visitor information covers. A gallery inside the wall is open, and the Airwalk - a steel and glass platform cantilevered eleven metres out over the downstream face - puts you above the full drop. A hotel stands on the crown.

History

The German AEG company drew up plans for a dam here in the late 1930s, and Austria took the project up again with exploratory drilling from 1957, but building began only in 1971, after an access road was cut up the steep Malta valley through six tunnels. Concrete was poured from 1973 in small lifts with water pipes to cool the mass, in snow, rain and winds of 80 kilometres an hour, and by 1977 the dam could begin to fill; at 42 metres below the top water level cracks opened at its upstream heel, strong in a U-shaped valley, and after regrouting in 1979 and 1980-1981 and later works, more than a decade of repairs passed before the reservoir could be used to the full (Wikipedia, Kölnbrein Dam).

What you'll find

• Austria's tallest dam - two hundred metres of double-curvature arch concrete.
• The Airwalk - a glass platform cantilevered out over the downstream face.
• A gallery inside the wall - the inspection route open to visitors.
• The remedial works - the structure added after cracking appeared from 1977, as the reservoir was first filled.

When to go

May to October; the road is closed by snow the rest of the year. Half a day.

What to expect

The toll road is long, steep and shut most of the year. Weather at 1,900 metres is often cold and cloudy. The Airwalk closes in wind and is not for anyone uneasy with heights.

Nearby

The Maltatal falls are down the road; Gmünd is at the valley mouth.

Key facts