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.

Hálslón Reservoir Full, Overflowing into Stuðlagil Canyon

Water levels in Hálslón reservoir, a storage reservoir connected to Kárahnjúkar Hydropower plant, reached their highest point late last Saturday night, Rúv reports. This affects the popular nature spectacle Stuðlagil in East Iceland, one of the largest basalt rock formations in Iceland. Travellers in the area should beware, as glacial water is now flowing out of the Hálslón reservoir, down to its old riverbed in Jökulsá á Dal river. The river flowing through Stuðlagil canyon is stronger than usual at this time of year. Some travellers have gone into the water this summer, putting themselves in risk. Entering the water now is believed to be even more dangerous, as the glacial water can easily grip people with it.

Water levels in Hálslón reservoir do not reach this high until ten days later on average. The Stuðlagil canyon emerged once the Kárahnjúkar hydropower plant diverted the riverbed in the area, creating the Hálslón reservoir in the process. Although the river Jökulsá á Dal still flows through the canyon, its water levels lowered significantly, revealing the basalt rock formation which had until then been hidden underneath the water. The murky glacial water stops overflowing from the reservoir in early October, giving the river back its blue-green colour.
Controversial power plant.
Kárahnjúkur hydropower, constructed in 2006, is the largest power plant in Iceland. It mostly provides power to the Alcoa owned Fjarðaál aluminum smelter in Reyðarfjörður. The project did not come without its critics, as the reservoir engulfed a large area of the highlands. The project is within an area that was previously the largest unspoiled wilderness in Europe. It covers over about 1,000 square kilometres in total and the rivers that supply water to the project are connected to Vatnajökull glacier, Europe’s largest. It has been severely criticized by environmentalists, especially author Andri Snær Magnason.