18 July 2018
Hidroituango: an update
I have not posted about Hidroituango (in Colombia) in the last few weeks, although the crisis has certainly not ended there. Seasonal changes in weather have meant that the inflows from the upper reaches of the catchment have reduced, allowing a slow reduction in water level. This has provided a welcome opportunity for the continued improvement of the dam, which is of course good news.
However, LAFM reports that last week a seismic event was recorded from within the power house cavern, which is interpreted as being a rockfall event. This has reduced the flow of water by 5 to 10%, with fears that this might become worse. One wonders about the state of the power house cavern, and indeed the remainder of the underground excavations, in light of these events.
Meanwhile, further imagery of the site has become available. Last week, Planet Labs collected a high resolution image of the site using their 0.8 metre SkySat instrument:
This highlights in particular the continued evolution of the slope failures just upstream of the dam, on the right bank:-
Meanwhile, some instability is evident on the slopes above the reservoir as the slow drawdown continues. This is to be expected. On 11th July Andres Posada tweeted this image of landslides on the slopes at Hidroituango:-
These slope failures can be seen on the Planet Labs imagery as well – this is a 3 m Planetscope image collecgted on 16th July 2018:-
Planet Team (2018). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://api.planet.com