Site Records

Quoich Power Station

OS Grid Ref: NH 10717 01186
Date opened: 1955
Date closed : Operational

Quoich, in the upper reaches of Glen Garry, is the upper stage of the Garry development - the discharge from Quoich power station contributes to the catchment of the lower stage, at Invergarry.

Completed in 1955, it's a relatively small station with a single 22MW generator, and a gross head of 331ft. It's the only 'conventional' surface station in the Garrry/Moriston scheme; all the others are totally or partly underground. It's a very straightforward simple installation.

Quoich dam is a massive rockfill structure, 126ft high, 1050ft long, and 336ft wide at the base.

From the dam, water is led to the power station by a low-pressure tunnel, 12843ft long, and horseshoe in section, with an equivalent diameter of 11' 6". There are no sidestream intakes.

The low-pressure tunnel terminates at the base of the surge chamber, which is of the orifice type, with an upper expansion chamber. The chamber is 169ft deep, the top 40ft being 45ft in diameter (the expansion chamber), the remainder of the shaft being 30ft in diameter. From the base of the surge chamber, the water falls down a vertical high-pressure shaft, 158ft deep by 11' 6" in diameter.

From the base of the shaft, the remaining distance to the power station is covered by a high-pressure tunnel 1440ft long, followed by a steel penstock tunnel 820ft long, to the main inlet valve.

Inside the station, the machinery consists of a single vertical Francis turbine and generator unit. Somewhat unusually this is mounted horizontally, not vertically - this design was adopted to make erection easier. The alternator is rated at 22MW, which corresponds to approx. 30,000HP at the turbine. Tailrace is directly into the River Garry.

Because the construction of the Quoich dam stopped fish from getting into the upper reaches of the River Garry, a fish trap was built across the river just downstream from the power station. Here migrating salmon can be taken and stripped of their eggs, which are taken to a hatchery.

There are 25 images of Quoich in the archives, and drilldown to high-resolution pictures is available; click on virtually any picture, and a high-resolution version will open in a new window.


Looking down to Quoich power station, from the main road above:

Quoich dam dominates the view from a considerable distance:

An archive view of Quoich power station, taken near the end of construction:

This drawing shows the whole scheme. It's a clickable imagemap; click on any of the pink-highlighted areas to bring up the relevant webpage:

Words and images © 2006 Michael J. Ross