Lochan Shira, Dam

This dam part of the Glen Shira hydro electric scheme to harness Shira and Fyne rivers and adjacent burns between Loch Fyne and Loch Awe. Completed 1956.

The Glen Shira Hydro-Electric project was designed to harness the Shira and Fyne and adjacent streams between Loch Fyne and Loch Awe. The Shira Dam is the centrepiece of the scheme and is 133 ft high and 2250 ft long. It is a mass concrete round-head buttress-type dam, the heads of the buttresses being of angular shape rather than truly curved as at Sloy Dam. The project generates 45MW.

The geography of the catchment area led to the construction of a smaller concrete and earth filled dam, 58 ft high, below the main dam to fully utilise the storage potential. This lower reservoir is also used for pumped storage to top up the upper reservoir as required. The high-pressure tunnel to the main dam’s power station is unusual in that it is a partly sloping shaft. It was driven almost entirely from the bottom, because the slope allowed most of the spoil to be removed with very little mechanical assistance.

The original scheme was conceived by James Williamson. The consulting engineers for the works as built were Babtie, Shaw & Morton and the main contractor was A. M. Carmichael of Edinburgh. The scheme was completed in 1956.

R Paxton and Jim Shipway 2007b

Reproduced from 'Civil Engineering heritage: Scotland - Highlands and Islands' with kind permission from Thomas Telford Publishers.

Shira Dam forms part of the phase II development of the Sloy catchment from 1959 onwards. The dam is a large scale round headed buttress dam with a central control tower and dispersal valve and small fixed spillway. The dam creates storage and flow regulation for Sron Mor power station (see separate item). Water leaves the dam via a tunnel through to the power station. This is a relatively large scale buttress dam set in a remote location in the upper reaches of Glen Shira. It is predominantly functional in design and of relatively standard engineering. P L Payne, 1988, 5; E Wood, 2002, 38; J Miller, 2002.

The Shira scheme

Dams were built at Lochan Shira, Lochan Sron Mor and the reservoir supplying Allt na Lairige power station via a tunnel. Sron Mor power station is fed by an aqueduct from Lochan Shira. Aqueducts and a long tunnel supply Clachan underground power station at the top of Loch Fyne at a head of 965 feet. Sron Mor was supplied with pumping facilities in effect to give Clachan the advantage of pumped storage. The installed capacity of the scheme is 51MW. Construction took place between 1951 and 1959.

Information from NRHE item catalogue number WP007424, compiled by George Walker, 2005.