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Mullardoch-Fasnakyle-Affric Hydroelectric Scheme
Fasnakyle, Glen Affric, Highland, Scotland, UK
Mullardoch-Fasnakyle-Affric Hydroelectric Scheme
associated engineer
Sir William Halcrow & Partners
date  1947 - 1952
era  Modern  |  category  Power Generation  |  reference  NH222312
ICE reference number  HEW 1421
photo  © and licensed for reuse under this
The Mullardoch-Fasnakyle-Affric Hydroelectric Scheme uses water from several lochs in and around Glen Affric to generate electricity at Fasnakyle in Strathglass. It was built for the North of Scotland Hydro-Electric Board and remains an essential component of Scotlandís electricity supply. Mullardoch Dam (pictured) is the schemeís major structure, and is also the largest concrete gravity dam in Britain.
Hydroelectric projects had been proposed for Glen Affric in 1928 and 1941. The first was rejected by Parliament in 1929 and the second was dropped in favour of the more comprehensive Mullardoch-Fasnakyle-Affric scheme. This scheme was approved in February 1946, and opened by HRH Duke of Edinburgh on 13th October 1952. It is located some 48km south west of Inverness and has a catchment area of 32,000ha.
Scheme structures include Mullardoch Dam, a tunnel between Loch Mullardoch and Loch Benevean, a smaller dam at the eastern end Loch Benevean and another tunnel from there to the main generating station at Fasnakyle. Both dams are of the mass concrete gravity type.
Construction of Mullardoch Dam began in 1947. Two years into the work it was decided to raise the height of the dam by 6.1m, a design change that required skilful execution. It is 48m high and 727m long and contains around 229,000 cu m of concrete. In plan, it consists of two wings meeting at an angle of 140 degrees on a natural island, with the apex pointing downstream (north east). There are two spillways, each 96m long.
The level of Loch Mullardoch was raised by 34m to 249m above sea level, forming a reservoir 13.7km long. Water from the reservoir is conveyed through a 4.4m diameter tunnel 4.8km long to Loch Benevean. This loch was dammed to raise its water level by 7m. A second 4.8km long tunnel, 4.8m in diameter laid to a gradient of 1 in 50, delivers water from Loch Benevean to Fasnakyle Power Station.
The tunnel divides into three pipelines at the power station to supply water to its three 22MW turbo alternators, with Francis-type turbines working under a gross head of 158.5m and each developing 24.6MW at 375rpm. A fourth underground generator was added when the station was extended in 2004-6.
The extensive project necessitated the building of two camps (at Cannich and Cozac) to house up to 2,000 people. Existing roads and bridges had to be widened and strengthened, and a 3.6MW temporary diesel generating station was installed. The multi-national workforce — British, Irish, Polish, Czech, German and Canadian — was nicknamed the 'Tunnel Tigers'.
Fasnakyle Power Station is built of sandstone and embellished with relief carvings by sculptor Hew Lorimer (1907-93). It was designated a Category B listed building in 1986, and upgraded to Category A in 1997.
Architect (Fasnakyle Power Station): James Shearer
Contractor: John Cochrane & Sons
Research: ECPK
"The Mullardoch-Fasnakyle-Affric Tunnels. Works Construction Division" by E.C. Dillon, in ICE Proceedings, Vol.8, pp.18-29, London, January 1950
reference sources   CEH SHI

Mullardoch-Fasnakyle-Affric Hydroelectric Scheme