Location type

Name and dates

Description

This is a large mass concrete dam (3112 ft long and 86 ft high) which was built for the hydro-electric scheme of the Loch Leven Water and Electric Power Co. It impounds the Black Water about 1000 ft above sea level to create the Blackwater Reservoir. The company owned the hydro-electric power station alongside the North British Aluminium Co Ltd's Kinlochleven Aluminium Smelter. It was completed in 1909 and provided hydro-scheme provided power to the smelter, company village of Kinlochleven and the locomotives of the 3 ft tramway which ran between a pier on Loch Leven and the smelter. The hydro-scheme is still in operation today but the smelter closed in 2000.

The Blackwater Reservoir has a capacity of approximately 24 billion gallons (about 3.8 billion cubic feet, although estimates in 1909 were for 3.3 billion cubic feet). The flooded area incorporated the small former lochs Lochan Inbhir, Lochan na Salach Uidhre and Loch a Bhaillidh and the resulting reservoir is about 7.7 miles long. Excluding additions made in the Great War, the catchment area was about 60 square miles with an average annual rainfall of around 100 in.

From the dam a concrete conduit (8 ft square), dropping slightly while following the contours, runs west for 3.5 miles on the south side of the Black Water (which becomes the River Leven below Dubh Lochan). Along the course of the conduit there are three additional intakes from water courses. On approach to the power station the conduit becomes a steep pipeline (a drop of 922 ft with six pipes of 39 in diameter) which runs downhill 935 ft. During construction a temporary railway with an inclined plane was laid along the north side of the pipes.

The dam was built by Robert McAlpine and the engineers were Thomas Meik & Sons. An aerial ropeway of four sections ran out from the pier on Loch Leven to the dam. To aid construction at the dam site there was a temporary railway parallel to the dam on its east side. A temporary shanty town of navvy cabins, workshops and concrete plant was established at the south end of the dam on its west side, where the aerial ropeway terminated. There were several deaths during the construction work and a small graveyard was laid out on a small hill just to the west. A small number of concrete headstones are within a small enclosure. Particularly poignant are the graves marked 'unknown' and that of a Mrs Riley. (If I recall correctly she was a cook and died in a fire at the camp.) Further navvies died on the long exposed walk from either Corrour or Rannoch stations across the moorland west to the dam, hydroscheme and smelter construction works. Most had reached the works via the contractors pier on Loch Leven pier or the walk from Ballachulish.

In the Great War the capacity of the hydroscheme was increased by diverting the outflow of Loch Eilde Mor, the Allt na h-Eilde. Both British soldiers and German POWs were employed on this work. A conduit runs south and the east from the loch to reach the north end of the dam on the Blackwater Reservoir.

The hydroelectric power station opened in 1909 with a 19,150 kW capacity (eight 3,200 horse-power turbines, driving eight 1,000 kW generators. It was upgraded in 1911 to an annual output of 150 million kWh.

There were repairs to the dam in 1963.

Tags