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Gleann nan Caorann, NW of Inverarnan, Dumbartonshire.
| NGR: | NN 29453 20419 |
| WGS84: | 56.34530, -4.76111 |
| Length: | 4300 m |
| Vert. Range: | 12 m |
| Altitude: | 327 m |
| Geology: | Garabal Hill - Glen Fyne Pluton / Ben Ledi Grit Formation |
| Tags: | Adit, Tunnel, ManMade |
| Registry: | second |
Tunnel, Hydro electric scheme.
N-S trending tunnel through bedrock, linking Gleann nan Caorann with Strath Dubh-Uisge (passing below the valley floor of the intervening Lairig Arnan). A northern tunnel portal on the S side of Gleann nan Caorann is connected with a surface aqueduct tunnel that runs along the S hillside and collects water from a number of streams via a number of intakes. These waters are transported to the S portal that probably opens into a pipe bridge in Strath Dubh-Uisge at [NN 29403 16110], and from this point the water follows an aqueduct until an outflow point towards the SW end of the valley at [28388 14876].
Alternative Names: Gleann nan Caorann - Strath Dubh-Uisge Tunnel
Notes: Given length & VR are approx (straight line distance between portals).
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This entry was last updated: 2025-10-15 03:55:35
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