Defence of critical infrastructure at Reykjanes peninsula


At around 20:45 UTC 19 March, a volcanic eruption began at Geldingadalur, in Fagradalsfjall on the Reykjanes Peninsula. In the past weeks, Verkís has worked on projects to defend critical infrastructure, including the mitigation measures (dams) currently under construction.

The project is a collaboration between Verkís and Efla, consulting engineers, the University of Iceland and the Icelandic Meteorological Office. But the project’s owner is Almannavarnir (the Department of Civil Protection and Emergency Management).

In the past week, two dams have been constructed in a neighbouring valley (South Meradalir) close to the eruption site in Geldingadalur, Iceland. The barriers are intended to delay the flow of lava down to Nátthagi, due to critical infrastructure in the valley and on the coast. Lava flow to the coast would entail disruption of transport along the Suðurstrandavegur the main road along the south coast.

The main dams were initially 4 meters high, with the possibility to increase the height to 8 m. This method to control lava flow and protect infrastructure and houses is known in many parts of the world where volcanic activity threatens settlements.

In Iceland, dams were built to defend inhabitated areas in Heimaey in 1973, but also in Kröflueldar 1975 to 1982. Overseas barriers have been constructed due to lava flows from volcanoes such as Mount Etna in Sicily, Italy in 1983, 1991-1992, 2001 and 2002; Kilaueu in Hawaii in 1955, 1959 and 1960, as well as in Japan in 1951.

The main purpose of building dams against lava flow is to direct the flow away from critical infrastructure or settlements. Dams are built to delay lava flow and/or collect it in a lava reservoir. More effective type of dams are deflecting dams, designed to deflect the moving mass down and away from protected areas.

If the barriers at the eruption sites in south Meradalir are not sufficiently high or strong to contain the lava flow, Hörn Hrafnsdóttir, civil and environmental engineer at Verkís, one of the on-site engineers managing the construction of the barriers, believes that the experience gained from the project will be enormously useful in the future if volcanoes at Reykjanes pennisula have awakened to life.

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