Aigas Power Station And Dam

Aigas power station with integrated dam is the penultimate station on the Affric scheme an makes use of water previously used by all of the other stations. The station is composed of an integrated turbine hall and dam. The dam is of mass gravity type, 91.5 meters long and 26 meters high. As well as providing a degree of storage the dam allows the regulation of the river flow. A large central drum gate is flanked by radial gates which allow the spill of the dam to be accurately controlled. This is essential in successful flood management as the dam is situated on a river system. The dam also has a Borland type fish pass. The turbine hall houses two Kaplan type 10MW turbines. The station was refurbished between 2002 and 2004, a project which included Aigas power station is a good example of an integrated dam and turbine hall utilising a steep sided river gorge for the generation of power. The design of the dam is relatively functional, with the detailing applied to the turbine hall well executed but relatively standard for the building type. PL Payne, 1988, 5; E Wood, 2002, 38; J Miller, 2002.

The Affric/ Beauly scheme

The work was begun on the construction of Mullardoch Dam in 1947. This is of the mass gravity type and is 2385 feet in length by 160 feet in height, impounding 7.5 million cubic feet of water. A tunnel was excavated from Loch Mullardoch to Loch Benevan, and another from the latter loch to Fasnakyle, the main power station on the River Affric, both tunnels being over three miles in length. The Fasnakyle tunnel splits into three steel-lined tunnels near the power station, each supplying a 22,000kW vertical Francis turbo-alternator.

The second stage of the scheme involved the Rivers Farrar and Beauly. Water is impounded in Loch Monar by the Monar Dam, supplying the Deanie power station at the west end of Loch Bennacharan which is dammed at the east end to feed Culligran power station, whose outflow to the River Farrar then flows into the River Glass. These power stations generate 38MW and 24MW respectively. The River Glass flows into the River Beauly which has dams and power stations at Aigas and Kilmorack, each a 20MW run of river station. These dams are provided with flood control, Borland fish passes and compensation water facilities with or without generation. The scheme was completed in 1963.

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