Site Records

Invergarry Power Station

OS Grid Ref: NH 31916 013025
Date opened: 1957
Date closed : Operational

Invergarry dam is a fairly modest structure, 50ft high and 150ft long. It was constructed in a gorge downstream of the original outlet of Loch Garry. The small size of the dam was a result of the requirement to minimise disruption of agriculture in the area; only a relatively small increase in the level of Loch Garry could be permitted, as valley grazing was already at a premium in this area.

This approach is consistent with the same design choices taken in the next Glen to the North; large upper reservoirs which flooded a lot of ground at Loyne and Clunie, a small lower reservoir at Dundreggan. Here the main storage is at Loch Quoich, with much less storage at Loch Garry.

Since the size of the

Invergarry dam, hidden away in a pretty gorge (the small culvert in the bank of the river is a fish bypass tunnel, designed to make the gorge easier for migrating salmon heading upstream):

This archive shot, taken just after completion of the dam, gives a better idea of the layout of the structure. A trash chute for passing floating debris on the left, then two discharge gates, and on the right the compensation water power station, and the entrance to the Borland fish lock:

Another archive shot. The dam on the right, in the middle the elaborate screens around the intake to the power tunnel, and on the extreme left the spillway channel leading to the spillway tunnel. A car can be seen on the track leading to the dam; the gatehouse for the power tunnel is out of sight, behind the knoll of rock to the right of the car:

This drawing makes the arrangements of tunnels, intake, and dam clearer:

And this drawing shows how the power tunnel intake burrows under the spillway tunnel:

Invergarry Dam - looking into the entrance of the spillway tunnel on the left bank:

Inside the spillway tunnel, looking back at the spillway. The small culvert visible in the base of the spillway is the emergency compensation water culvert mentioned on the drawing above:

In the spillway tunnel, looking downstream. Your intrepid explorer gives scale - it's a fair sized tunnel, 24ft equivalent diameter:

Spillway tunnel exit from the outside in low water:

The spillway tunnel discharges on the left bank of the river a few hundred feet downstream of the dam. The exit, from the inside, in high water:

An archive shot of the tunnel under construction, take from almost the same position as the above shot:

Another archive shot of the spillway tunnel under construction; it was used to divert the flow of the river whilst the dam was being constructed:

Words and images © 2006 Michael J. Ross