23 January 2019
Bureya Reservoir: blasting has started to clear the landslide dam
The website Rivers Without Boundaries is reporting that works have now started to clear the landslide dam at Bureya Reservoir in Russia. You will remember that this is a large, valley blocking landslide that occurred on 11th December 2018. This generated a bit of a flurry of interest because some parties ascribed this event to a meteorite impact event, which is highly unlikely to be the case. However, the landslide dam is significant and, of course, potentially dangerous, so the authorities are rightly attempting to clear the blockage.
Rivers Without Boundaries report that in the first instance about 10 tonnes of explosives have been used in an operation that involves 400 people:-
Rivers Without Boundaries point out that the effects of these operations can be seen in satellite imagery – and indeed this is the case. This is a Planet Labs image collected on 21st January. The channel being excavated using the explosives can be seen clearly:-
Operations are expected to take about nine days to clear the blockage.
Further examination of the causes of the Bureya Reservoir landslide
Interestingly, the Rivers without Boundaries has another piece that looks in more detail at the potential causes of the landslide. It rightly rejects the impact hypothesis. Most interestingly, it provides details of changes in the water level of the Bureya Reservoir in the period leading up to the collapse:-
“As we know now the site of the landslide, despite being 100 kilometers from the dam of Bureyskaya Hydro, experiences regular significant change in water level ranging from 237.6 m above sea level meters on May 25, 2018 to 253 meters ASL on December 12, 2018 (difference more than 15 meters). The landslide on Bureya occurred during the period of intensive reservoir level drawdown (5-12 centimeters a day), that is the usual phase in which other reservoirs are known to trigger landslides. So, the draw down of reservoir may well be a major factor in that case, and there is certainly a need for the owners of the dam to monitor the site carefully for other land-slide prone slopes.
“According to early reports from Dr Aleksey Makhinov, leading geomorphologist in the region, who visited the spot on December 26, the failed slope’s toes were regularly flooded in recent past. Other experts suggested it could be exacerbated by ice-cover formation on December 9-14 and by water freezing in the cracks.”
Rapid draw down is a far more likely cause than is an impact event, especially as the satellite imagery suggests that he slope had deformed prior to the collapse.
Planet Team (2018). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA.