Site Records

Glenmoriston: Dundreggan Dam

Dundreggan dam, conspicuously located at the side of the A887 between Loch Ness and the West coast, provides the daily pondage for Glenmoriston power station. A fairly modest gravity dam, only 55ft high and 400ft long, it contains a small compensation water generating set, the intake for the Glenmoriston power station, and the head of the cable/vent shaft which runs down to Glenmoriston power station, which is located 300ft vertically below the dam.

The dominant feature is however the three large gates - two radial gates, flanking one tilting gate - which are required to pass the occasional exceptionally severe spates encountered here - the catchment area of the dam is very large in relation to the size of the reservoir, as it sits at the bottom of a 'cascade' development - the tailwaters from Livishe and Ceannacroc power stations also end up here.

The transformers and high-voltage switchgear for Glenmoriston power station are situated adjacent to the dam.

The buildings contain the compensation set, offices, and the head of the cable/vent shaft - the position of the vent shaft is clear from the inverted conical 'chimney' at the left end of the building:

A helpful drawing makes the layout clear. It should be noted that the 'lift shaft' mentioned on the drawing no longer contains a lift, just a staircase - the lift to the power station was removed during refurbishment in 1999:

Inside the buildings - the head of the cable/vent shaft. The cables can be seen running off to the left, where a cable tunnel takes them to the transformer compound.

Looking down the shaft; it drops 300ft / 100M vertically to the power station. Contains the cables, the vent ducts, and the stairwell.

Looking at the rear face of the dam from across the reservoir; the structures on the left bank are the screen rake/lift gantry for the intake:

The intake in more detail - the gatehouse, and the curved 'mancatcher' screen in front of it. The vertical high-pressure shaft which takes the water to the power station is located immediately behind the gatehouse:

The radial gates passing a moderate flood (apologies for poor image quality)...

...and the effect on the river immediately below the dam.

One from the archives - dam nearing completion (note work still in progress above the gates)

Words and images © 2005 Michael J. Ross