Hólmsárvirkjun

RARIK Energy Development (RED) has been working on planning and preparation for Hólmsárvirkjun hydropower plant with Landsvirkjun since 2008. In January 2011 RED officially handed the project over to Orkusalan ehf. RED will none the less help Orkusalan ehf. managing the project’s design and environmental impacts, at least for the next foreseeable years.

The river Hólmsá is located in south Iceland and originates southeast of Torfajökull glacier. Hólmsá runs south-east along moorlands Ljótarstaðarheiði and Snæbýlisheiði until it ends up in Flögulón lagoon, there it merges with river Kúðafljót which runs from Flögulón to the sea. There are two waterfalls in Hólmsá; Hólmsárfoss waterfall is localized 400 to 500m upstream from the prospective reservoir at Atley and Hrossafoss waterfall is downstream from Atley. Several rivers that originate in glacier Mýrdalsjökull merge with the river and the runoff is a combination of groundwater, glacial melt water and direct runoff.

Hólmsárvirkjun hydropower plant will be located in Vestur-Skaftafellssýsla, northeast of Mýrdalsjökull. The fall of Hólmsá will be harnessed from Atley down to Flögulón lagoon. It is planned to put a dam nearby Atley to form Atleyjarlón reservoir. From there the water will be redirected through a headrace tunnel to an underground powerhouse with tailrace to Flögulón. Flood protection bunds will be put up at southwest corner of Atleyjarlón reservoir to protect the lowlands around the river, flood protection bunds will likewise be put up nearby Flögulón to protect the lands of Flaga and camping grounds at Hrífunes.

Hólmsárvirkjun will have impact on hydrology of the area between Hólmsárfoss and the confluence of Hólmsá and Kúðafljót, Hólmsárvirkjun will however not change the flow of Kúðafljót to the sea. The dam will be hardly noticeable from distance because it will be in a small ravine. Hólmsárvirkjun will have no effect on Hólmsárfoss but it’s unknown how much Hrossafoss will change.

Landsvirkjun and RED originally planned to harness the fall of Hólmsá from Einhyrningshamrar east of mt. Einhyrningur down to waterfall Bjarnafoss in river Tungufljót. The main environmental impacts of that option are that the mean flow of river Hólmsá downstream of the headrace will be reduced by 28m²/s and the flow of river Tungufljót downstream of the tailrace will increase correspondingly. That option was discarded because having the reservoir at Atley is equally economically feasible and more environmentally friendly. 

Key figures of Hólmsárvirkjun with a reservoir at Atley