Reservoirs Swell, Leading to Possible Overflow for Several Hydroelectric Dams

blönduvirkjun power plant iceland dam

In a recent report by Iceland’s national energy company, Landsvirkjun, reservoirs throughout Iceland are said to be reaching full capacity.

The public report can be seen below in  Facebook post from Landsvirkjun. 

According to Landsvirkjun, Blönduvirkjun power station, located along the Blanda river in North Iceland, began to overflow this past Thursday, September 1. 

Hálslón, one of the reservoirs for the Kárahnjúkar hydroelectric dam, also began to overflow September 5, causing the 100m man-made waterfall known as Hverfandi to appear. Hverfandi, known literally as “vanishing” or “disappearing,” is called this because it only flows when the reservoirs spills over.

According to Landsvirkjun, it has been a good summer for energy production, with nearly all reservoirs nearing capacity. Hágöngulón, a reservoir in the central highlands, and Kelduárlón, a part of the Kárahnjúkar system, were both full already in July. Þórisvatn remains the only other major reservoir to not reach its peak capacity.

Þórisvatn is currently rising by some 3-4cm per day, but it is unclear if it will reach its overflow point this year. Last year, its highpoint was reached at 576m, 3m shy of its 579m capacity.

Arctic Hydro Planning Hydroelectric Station in East Iceland

The Iceland-based company Arctic Power is in the planning phase for constructing a hydroelectric power station in the Fljótsdalshérað district of the East Fjords, RÚV reports. The plant would be located on the Geitdalsá river and would also include an intake reservoir of nearly three-square kilometres in Leirudalur valley, which lies to the east of Hornbrynja mountain. A two-year research phase is being initiated in advance of project construction and will include an environmental assessment that is set to take place this summer. The final scale of the station and its accompanying reservoir will depend on what the company discovers during this research phase, but it’s expected that the plant could potentially be up and running within the next five years.

The plans for the project have been underway for quite some time, but Arctic Hydro has now requested changes to the Fljótsdalshérað land use plan, which is why a new environmental assessment needs to take place.

Multi-Dam System

The power station would be fed water via a multi-part system of dams and natural river channels. Its intake reservoir is currently planned to hold 30 gigalitres of water. (One gigalitre is equivalent to a billion litres.) To accumulate this quantity of water, a dam would first need to be constructed on the Leirudalsá river that would be one km [.62 m] long and 18 metres [59 ft] high. The water would be channelled out of this intermediate reservoir down the Leirudalsá river and then down the Geitdalsár river into the intake reservoir. This would also require the construction of a dam measuring 300 metres [984 ft] long and 32 metres [104 ft] high at the point where this river meets the Ytri-Sauðá river.

The water in the intake lagoon would then flow into a 6.6 km [41 m] down pipe, fall 230 metres [755 ft], and from there flow into the power station itself, where electricity would be created by the power station’s turbines and then transported another 17 km [10.5 m] via underground cables to the Landsnet substation at Hryggstekkur.

Scaling Expectations

“We’ve been looking at an 8-15 MW power station,” explained Arctic Power CEO Skírnir Sigurbjörnsson. “But based on flow studies, it seems like 9 MW would be most suitable. “…A nearby example that locals are familiar with is the lagoon for the Seyðisfjörður power station—when you drive over Fjarheiður heath into Seyðisfjörður. This would be on a similar scale to that, I’d say.” Skírnir continued that the final size of the reservoir and the power station itself will be determined after further research and the results of the environmental assessment. A draft of the assessment plan will be published in the next few weeks.

Skírnir also said that the new power station and reservoir would have additional side benefits for the region. For one, the dam system for the new reservoir would create a more uniform water flow on the rivers, which, during the winter months in particular, would mean better utilisation potential for the existing power station on the Grímsá river, further down in the catchment area. Arctic Hydro would also create a new service road into Geitdalur and Leirudalur valleys, which Skírnir says would increase access to the area and connect to a trail that runs from Öxi í Bjarnarhíð.

Fljótsdalshérað would also generate income, Skírnir said, through the power station’s property taxes as well as the fee that the company would pay to rent water useage rights from the district. The district currently holds half of the rights, the Icelandic government the other half. For the first five years, the rental agreement would see 2.5% of all of the power station’s earnings be paid in return for water usage rights, but this would then go up to 5%, and finally 10% in stages, over 30 years from the time the power station opens.

See a diagram of the current power station dam and reservoir plan here.