Loch Monar Dam

Monar Dam provides the main storage capacity for the Glen Strathfarrar section of this scheme. The dam is of arch type taking the form of a shallow double arch – first of its kind in Britain. Using this construction method in the tight gorge like site of the dam saved around 9% in cost and materials. Water leaves the dam via tunnel and pipe over a distance of 9 km to Deanie power station (see separate item). The tunnel inlet is controlled by a gate housed in the gatehouse adjacent to the upstream face of the dam. This dam has a significant degree of technical interest as derived from the use of the double curvature construction method and the pioneering early use of this technology. The dam also makes a significant landscape contribution. Set within a narrow gorge it is a soaring wall of concrete set between steep rock walls. This is emphasised by the concave curve of the wall. The inlet gatehouse tower is also of strikingly modern design with concrete piers screening the inlet gates a set at a dramatic angle to the water. National Archives of Scotland (NAS), Ref: NSE North of Scotland Hydro Electric Board Collection (1943 -1990); NAS, Ref: NSE1 North of Scotland Hydro Electric Board Minutes (1943-1990); NAS, Ref NSE2 North of Scotland Hydro Electric Board Annual Reports (1943-1990); PL Payne, 1988; J Miller, 2002, 52: E Wood, 2002, 81; Scottish Hydro Electric, 2000, 12.

http://canmore.rcahms.gov.uk/en/site/173015/details/loch+monar+dam/

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.