19 May 2014
Dariali Valley: a valley-blocking landslide that has killed three and left five missing
Posted by Dave Petley
Late last week a landslide occurred in the Dariali Valley in Georgia, killing three workers from a hydroelectric project, and leaving a further five missing. The landslide, which is estimated to be about 1 million cubic metres, was triggered by heavy rainfall. Whilst images of the landslide are not plentiful as yet, this one suggests that it has blocked the river:
Democracy and Freedom Watch have a good article about the landslide, which indicates that the landslide has severed the gas pipeline that links Russia and Armenia and the road between Russia and Georgia. There are also concerns about flooding as the lake builds. Looking at the image below, those concerns are well-placed:
However, this article today plays down the risks and indicates that water may have started to flow past the blockage.
The Dariali Valley landslide and the hydroelectric scheme
Apart from the obvious threat that the landslide poses, an interesting aspect of the event is the potential link to the Dariali Valley hydroelectric project. I have written previously about the worryingly high incidence of fatal landslides associated with these projects in high mountains. Democracy and Freedom Watch notes that the issues of landslides associated with this project had been highlighted previously. There is no evidence to link the project with the landslide at this stage, but in the first image above parts of the hydroelectric scheme, under construction, are visible. This is in contrast with this article, which states that the landslide was 20 km from the site of the hydroelectric scheme. Agenda.ge has an article that attributes the landslide to “extreme movements of an icy glacier located high on a mountain peak”. I am not sure what this means.
The slide location was 20km from the dam. Any idea if there are any geologic maps of the area that may be available? Was the pipeline that was ruptured the recently built BP gas line? If so, there may environmental (geology) studies in the Env. Impact assessment report showing the orientation major faults in the area (past earthquakes reports etc.) as well as a risk assessment of potential rock slides. I don’t want to suggest any causes for the slide because its early but I would start there.