The Cruachan Reservoir is 396 meters (1.299 ft) above Loch Awe, and is 316 meters (1,037 ft) long. The reservoir has a length of 23 square kilometers (8.9 sq mi), and is capable of holding 7 gigawatt-hours (25 TJ) of energy. Environmental regulations meant that the dam had to have a "clean" structure, so the operational equipment is located within the dam itself.
The penstocks are a pair of tunnels, 260 meters (850 ft) long and inclined at 56 ° from the horizontal with a 5.3 meters (17 ft) diameter, which then bifurcate into four steel lined 190 meters (620 ft) long, 2.5 meters (8 ft 2 in) diameter shafts. The penstocks underwent a major inspection and refurbishment in 2003.
The Cruachan Reservoir is 396 meters above Loch Awe and is surrounded by a 316-meter dam. The reservoir has a catchment area of 23 square kilometers, and is able to hold 7 gigawatt hours (25 TJ) of energy. Environmental restrictions called for the dam to have a "clean" structure, so the operating machines are inside the dam wall itself. The pressure tubes consist of a pair of tunnels, 260 meters long and inclined 56 degrees from the horizontal, with a diameter of 5, 3 meters, which then branch into four steel-lined 190 meter long, 2.5 meter diameter shafts.
The pressure pipelines were subjected to a thorough inspection in 2003.