Sigalda Hydropower Station
Sigalda Station is a very distinctive landmark, standing by itself in the otherwise deserted central highlands some way south of Lake Thorisvatn. There are no other buildings than the power station itself and routine maintenance is handled from Hrauneyjafoss Station, 10 km away. Landsvirkjun followed up the Burfell project by building the Sigalda Station from 1973 to 1977, when it went on line. The station has three 50 MW turbine units. A dam has been built on the River Tungnaa in the upper part of the chasm above the Sigalda hill, to form a 14 km² reservoir, Krokslon. The water is diverted along a 1 km headrace channel through the hill to an intake point on its west edge. From there, three pressure shafts descend a 74 m head to the powerhouse which has been built north of the river at the foot of the hill, partly set into it. A 550 m tailrace channel leads from the powerhouse to the reservoir above Hrauneyjafoss Station. The 925 m Sigalda dam is made of rockfill with asphalt surfacing on the side facing the water, and measures 40 m at its highest point in the chasm.