Hálslón, the reservoir of the Kárahnjúkar power plant in the eastern highlands, filled up on Tuesday and now water from the lagoon will overflow into the channel of the glacial river Jökulsá á Dal. Increased river flow can be expected as a consequence.
A view of the Hálslón reservoir and the gorge where Jökulsá á Dal flows.
When the overflow tumbles over the cliff the spectacular waterfall Hverfandi (“Vanisher”) is created. It disappears again once the surface of the reservoir starts to drop, Fréttabladid reports.
Hálslón filled up rather late this year, which can be explained by the unusually cold spring. Last year the dam was full by July 28, which is unusually early.
In related news, the Ministry for the Environment concluded prior to the building of the dam at Kárahnjúkar ten years ago, that it would not have a significant impact on conditions in the lake Lagarfljót in east Iceland, ruv.is reports.
According to ruv.is, the contrary has now come to light with a decline in the number of trout in the lake.
With the dam’s establishment, Jökulsá á Dal was made to flow into Lagarfljót. Glacial sediment makes the water murky, which makes it more difficult for the trout to thrive.
Sunlight doesn’t reach as far into the lake as before leading to a reduction in photosynthesis, which eventually reduces food for fish.
Gudmundur Hördur Gudmundsson, chairman of the NGO Landvernd (Icelandic Environment Association), believes the ministry’s decision must be investigated.
“I know, for example, that information from the Icelandic Institute of Natural History was not sought at the time,” he said. “The ministry must explain what reasons it had to come to this conclusion.”
Click here to read more about Hálslón.