In the Beginning - The Legend of Ben Cruachan

One wall of the machine hall at Cruachan is a mural of inlaid woods, by artist Elizabeth Falconer, which depicts the legend of Cruachan.


The intricate mural tells the tale of the Cailleach Bheur, or Old Hag of the Ridges, who was the guardian of a fountain that welled up from the peak of Ben Cruachan.

Her duty was to cover the spring with a slab of stone at sundown and lift away the rock at dawn. One evening she fell asleep and the well overflowed.

The water, rushing down the mountainside, burst open a new outlet to the sea through the Pass of Brander. By the time the Cailleach awoke, the water had flooded the wide strath below and drowned all the people and their cattle.

Legend says this is how the River Awe and Loch Awe were formed. The Cailleach was turned to stone as punishment for her negligence and sits to this day, high on the mountain, above the Pass of Brander.

Concept & Construction

Cruachan power station was constructed between 1959 and 1965. It was the first reversible pump storage hydro system on this scale to be built in the world.

Power station construction

Cruachan was the brainchild of Sir Edward McColl, from Dumbarton, who came up with the whole concept in the 1930s. Tom Johnston, a native of Kirkintilloch, wartime Secretary of State for Scotland, and a huge advocate of hydroelectric power, forced the scheme through Parliament in 1947.

Power station construction

The designer of Cruachan was James Williamson, an engineer from Lanarkshire.

During the six years of construction, there was a large workforce of 1300 men, affectionately known as the Tunnel Tigers. The men used hand held air drills to bore holes in the solid granite rock, which were then packed with gelignite and blasted.

The first plant items to be installed in the cavern were the turbine casings, which were mounted at the lower levels within the cavern.

Power station construction

A 275,000V transmission line was constructed to carry the power from the top of the cable shaft just in front of the dam, to Dalmally substation, five miles east of Cruachan, and then on to Windyhill, north of Glasgow. This line passes through rough terrain, and at its highest reaches 1800 feet (549 metres). 

Power station construction


The power station was officially opened by the Queen on 15th October 1965. Two of the machines were completed at this time, with the remaining two coming into service in 1966 and 1967. 

The Queen Opens Cruachan Dam

The Queen Opens Cruachan Dam

Video clip: Click the image above to view a film from British Pathé News in 1965 showing the Queen opening Cruachan Dam.

Cruachan, when built, was the highest head reversible pump/turbine power station on this scale in the world. A lot of time was spent at the design stage, optimising all aspects of construction and operation. Many working models were built of the turbines and work tests were carried out on complete alternators before shipping to site. Because of the limitations of local roads and the size of the access tunnel, all the equipment had to be broken down into manageable loads for transportation.


In the Beginning

The Creation of Lochawe by Cailleach Bheur, Old Hag of the Ridges


Edward McColl presents the concept


Tom Johnson passes the Hydro Bill through Parliament


James Williamson designs Cruachan


Construction begins


Cruachan Power Station is opened by Her Majesty Queen Elizabeth II


Cruachan can generate 440MW of electricity to meet times of peak demand on the National Grid