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Mullardoch Tunnel [Outfall]

Loch Benevean (Loch Beinn A' Mheadhoin), Glen Affric, Inverness-shire.

Tunnel, Hydro Electric scheme.

"The Mullardoch tunnel is some 17,100 feet (5,200 m) long, and falls by just 3 feet (0.9 m) over its entire length... The largest dam of the [Affric-Beauly hydro-electric power] scheme is at Loch Mullardoch, at the head of Glen Cannich... From the dam, a tunnel takes water to Loch Beinn a' Mheadhoin in Glen Affric, via a small underground power station near Mullardoch dam. Tunnelling began in 1948... while that from Loch Mullardoch was finished in late 1950. John Cochrane and Sons were the contractors, and much of the process was mechanised, due to a shortage of labour." [Wikipedia]

Virtually all of the tunnel system is unlined. [Corestore]

Alternative Names: Loch Mullardoch - Loch Beinn A' Mheadhoin Tunnel, Benevean Tunnel

Notes: "The outfall on the site of the tunnel from Loch Mullardoch to Loch Benevean, on the side of the latter loch. The rocky slope, with scrub birch and pine trees is typical of the area in which the project was constructed and great care was taken in its design and construction to minimise the impact on the fine scenery in the area." [RCAHMS, on Trove]

"the actual [outfall] mouth of the tunnel is underwater, but not by much. I've been told that when Loch Benevean is at its lowest level, the mouth of the tunnel is visible and the tunnel flows freely, with airspace. There's a major construction adit on the left side of the track which leads to the outfall, around 50 yards before the outfall itself. It's still used for maintenance access when the tunnel is dewatered." [Corestore]

Hydrographic Feeds: Loch Mullardoch

Hydrographic Resurgences: Loch Benevean