Hydrology and hydrodynamics

Kárahnjúkar hydropower - Ufsarstífla dam / Hrauna­veita diversion

Jökulsá in Fljótsdalur - Iceland

Verkís services was design of rockfill dams and flood control structures (spillways and bottom outlets), structural design and mechanical design (gates in tunnels and bottom outlets).

 Sizes: 935.000 m3
 Project time:  2005 - 2008

Project overview:
The water diversion project is a part of the Kárahnjúkar H.E.P. The Hraunaveita diversion diverts four rivers in the highlands of Múli and Hraun into the Ufsarlón reservoir that is formed by the Ufsarstífla dam in the Fljótsdalur valley. The water in the reservoir flows into the Jökulsárveita tunnel that joins the headrace tunnel of the Kárahnjúkar H.E.P.

The project consist of four dams, two diversion tunnels and canals. Furthest is the Sauðárdalur dam which directs the inflowing water through a canal to the Inner Sauðá river which is connected to the Grjótá river by another canal. The Grjóta river will be dammed and water diverted through a tunnel into the Kelduá river. The Kelduár dam diverts the water to the Ufsarlón reservoir. Finally, the inflowing and stored water of the Ufsarlón reservoir that is formed by the Ufsarstifla dam is diverted into the headrace tunnel of the Kárahnjúkar H.E.P. as needed.

Excavation (dam foundations and canals) 935.000 m3, filling in dams 1.335.000 m3, tunnel excavation 66.000 m3, concrete and shotcrete 18.500 m3.