The total land area impacted by the Karahnukar Dam Project is approximately 290,000 hectares, or close to 3% of the total areal of Iceland. It includes the catchment areas of two major glacial river systems.
The proposed project will impact vegetation in three major ways:
About 4000 hectares of lush highland vegetation (above 600 meters above sea level) with high grazing and protection value will be drowned under the planned reservoirs. Although not a very large area per se, this is a significant proportion of the remaining highland vegetation of Iceland, which has been retreating through the ages as a result of unsustainable use and erosion.
The fluctuating water level in the main resevoir Halslon will, in late winter and spring, result in a 24 km long mud zone, which is is bound to form a dust bowl or “erosion trap” in dry and windy conditions. Blowing dust and soil will damage or drown neighbouring vegtation and thus increase the effective impact zone. Mitigating mechanisms proposed by the Power Company, including rock walls around the reservoir and mechanical irrigation systems, are by themselves large infrastructures which seem to call for an independent Environmental Impact Assessment.
Finally, the planned relocation of water from one major glacial river system and tributaries into another will alter the groundwater balance over an extensive area with largely unknown immediate and long-term cumulative impacts effects on the vegetation of those areas.
It is known that the proposed project will severely impact certain species of wildlife, while its cumulative and long-term impacts on the local fauna remain poorly understood.
The feral reindeer population on Iceland (introduced from Norway in the early 18th Century, but since then free-roaming and thus in fact wild) is evenly split between the eastern central highlands of Iceland and neighbouring eastern fiords. The highland herd, comprising approximately 1,500 animals, will be severly impacted or even destroyed by the Karahnjukar Dam project as the planned reservoir is centered in its main breeding area as well as in key spring grazing area. Furthermore, studies are accumulating that confirm the highly negative distrubance impacts of development activities on wild reindeer.
The Karahnukar project, with its many reservoirs, channels, roads, dumps, and power lines, will ruin approximately 500 nesting places of the pink-footed goose, which exceeds the international RAMSAR Convention threshold (1%) of the breeding population.
A large Harbour seal rookery (3% of the total population), which is located at the mouth of the glacial river (Jokulsa a Dal) that will be dammed and diverted, will likely be irreversibly damaged and abandoned as a result of reduced water flow.
Due to increased mud and sediment content and resulting decrease in visibility in the receiving river, its divers fauna of freshwater salmonid fish faces an uncertain future.
The area that will be inu ndated by the Halslon reservoir is inhabited by diverse invertebrate fauna, including several rare and endangered species.
It should be emphasised that these are the some of the major and obvious impacts on the flaura and fauna of the area impacted by the Karahnukar project. The long-term cumulative impacts of this by far largest infrastructure development in the history of Iceland remains to be seen.