Tummel Hydro-Electric Scheme
A hydro-electric scheme constructed initially for the Grampian Electricity Supply Co.
1930 A dam and diversion works were built at the outlet of Loch Ericht to provide a water supply to the new Rannoch hydro-power station; the Ericht Hydro-Electric Scheme was brought into operation at the end of 1930.
1933 The Tummel Scheme was constructed using Loch Rannoch as a water storage area with a regulating barrage across Loch Rannoch, a second barrage to form the Dunalastair reservoir, and the Tummel bridge power station. This was completed in 1933.
The outlet to Loch Rannoch is the River Tummel; the water passes down the river to the reservoir formed by the intake dam about 5 miles down the River Tummel. On the south bank, water is taken off through screens into the Tummel Aqueduct which follows a contour along the hillside for a distance of about three miles.
Before entering the power house each pipe line is provided with a Venturi pipe for measuring the flow. The head is 170 feet and there are two horizontal generating sets each of 24,000 h.p. generating current at 11,000 volts, 50 cycles per second, three phase at 300 r.p.m.
The works were designed and constructed by Messrs. Balfour Beatty and Company of London; and Mr. W. T. Halcrow of Messrs. C. S. Meik and Halcrow acted as advising civil engineer to the owners.
1954 A further scheme, the Tummel-Garry scheme, was built for North of Scotland Hydro-Electric Board. This further developed the resources of the entire catchment. Power stations were built at Pitlochry, Clunie and Errochty.
1955 The North of Scotland Hydro-Electric Board promoted two additional schemes, to complete the utilisation of hydro-resources already substantially achieved by the Tummel-Garry scheme. Small additional power stations were built, one on Loch Ericht at the outfall of the Loch Garry-Loch Ericht tunnel, and one near the River Truim, to make use of flows already diverted by existing works.