Kárahnjúkastífla

Background

History & Background

The Kárahnjúkar hydropower project moved into full construction in 2003 following the energy agreement connected with the Fjardaál aluminium plant in Reyðarfjörður. At the dam site, Jökulsá á Dal was diverted through tunnels while Kárahnjúkastífla was built as a concrete-faced rockfill dam. Filling of Hálslón began on 28 September 2006. During 2006 the final major dam-fill materials were placed and the upstream concrete face was completed; finishing work on the dam crown continued into 2007. Fljótsdalur Power Station entered service in 2007, with its formal start-up on 30 November. The finished system links highland reservoirs, about 72 km of tunnels and an underground powerhouse in Fljótsdalur.

Kárahnjúkastífla is the largest dam in the Kárahnjúkar–Fljótsdalur hydropower system and one of the most striking man-made landmarks in Iceland’s eastern Highlands. The concrete-faced rockfill dam crosses Jökulsá á Dal at Fremri Kárahnjúkar. Landsvirkjun’s current technical data gives a maximum height of 198 metres, a length of 700 metres and approximately 8.4 million cubic metres of fill material. Together with the smaller Desjarárstífla and Sauðárdalsstífla dams, it forms Hálslón, the main storage reservoir for Fljótsdalur Power Station. At full level, Hálslón covers about 63 square kilometres and stretches roughly 25 kilometres through the highlands. Water from the reservoir ultimately travels through the extensive tunnel system to the underground Fljótsdalur Power Station, which came online in 2007. The station has an installed capacity of 690 MW, and much of its electricity has historically been supplied to the aluminium plant in Reyðarfjörður. For travellers, Kárahnjúkastífla is also a dramatic viewpoint. The open highland setting gives wide views across Hálslón, while part of Hafrahvammagljúfur can be seen from the dam area. The canyon reaches about 200 metres in depth at its highest sections. In late summer, when Hálslón is full enough to spill, the overflow creates Hverfandi, a seasonal waterfall that plunges about 100 metres into the canyon. Access is unusually straightforward for a highland landmark when the summer road is open: Road 910 from Fljótsdalur is paved all the way to the dam and can be driven in an ordinary car in suitable conditions. The road beyond the dam becomes F910 and is only for high-clearance 4x4 vehicles when officially open. Weather and road conditions can change quickly, so visitors should check current road information before travelling.