Loch Sloy Dam

Loch Sloy Dam forms the storage reservoir for Sloy power station (see separate item). The dam is of buttress type with a fixed spillway to the centre and integrated tunnel intake gatehouse to the upstream side of the dam allowing water to enter the tunnel through to the power station. The dam is 56 meters high and 357 meters long. This large dam is of pioneering design, which was first proposed by prominent dam designer James Williamson in a lecture in Washington DC in 1936. The buttressed design represented a significant saving in materials over the construction of a traditional mass concrete gravity dam. This type of dam was increasingly commonly used in the later schemes developed by NoSHEB, under the influence of James Williamson who was the lead member of the NoSHEB technical panel. P L Payne, 1988, 5; E Wood, 2002, 38; J Miller, 2002.

The Loch Sloy hydro electric scheme

This was the first scheme to be tackled in 1945. Serious problems arose due to the post-war shortages of manpower and materials. The first of these was addressed by using hundreds of German prisoners of war. Access problems required the building of roads and conveyors for materials landed from Loch Lomond. Severe weather conditions delayed progress and the project was not completed until 1950.

A dam of massive buttress type was built at the south-eastern end of Loch Sloy leading to a tunnel through Ben Vorlich, followed by four circular pipelines leading to to the Loch Sloy power station at Inveruglas on the side of Loch Lomond. A surge shaft was incorporated in Ben Vorlich.

The generating sets consist of four vertical shaft Francis turbines each coupled to a 32,500 kW alternator. Delays due to adverse weather continued and transport problems for the heavy equipment which was finally installed by 1950. When fully loaded the turbines pass a million gallons of water per minute.

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