The main purpose of the project is to collect the glacier waters of the Jokulsa a Dal river in the Halslòn reservoir, for subsequent transfer to a 690 MW underground powerhouse. The electric power generated will be used to run Iceland’s largest aluminium production plant (more than 350,000 t/y).
The concrete-faced rockfill dam is 193 m high, with a crest length of approximately 730 m and a rockfill volume of 8.9 million m³.
The river diversion works comprise two tunnels with lengths of 764 m and 845 m respectively, excavated using traditional methods. The bottom outlet consists of a 60 m high, 5 m diameter surge shaft, discharging into one of the two diversion tunnels.
The headrace tunnel is approximately 39 km long, of which a section of 35.3 km excavated using three full-face TBMs, two with a diameter of 7.20 m and the third with a diameter of 7.60 m; the remaining 3.7 km section was excavated with traditional methods. Additionally three adits were excavated, as well as a secondary headrace tunnel and drainage tunnel (overall length 16.6 km) and two valves chambers for a total volume of 13,425 m³.
|MAIN TECHNICAL DATA:|
|Dam rockfill embankmen: 8,900,000 m3|
|Concrete works: 178,050 m3|
|Underground excavation works: 2,300,000 m3|
|Underground concrete works: 50,850 m3|
Karahnjukar hydroelectric project