16 January 2019
New problems at Hidroituango
Last year I wrote on a number of occasions about the major problems at the Hidroituango hydro-electric project in Colombia. In the last few days new problems have emerged, although there has been very little international coverage. Last Thursday, EPM (the dam operator) announced in a press conference that a significant void had been discovered in the rock mass close to the dam. The only reports that I can find are in Spanish; Noticias Caricol has a good report that Google Translate seems to be able to interpret:-
This Thursday at a press conference EPM gave details of an unexpected discovery that is the subject of research in the project.
The manager in charge of EPM, Jhon Maya Salazar, in the company of the mayor of Medellín, Federico Gutiérrez, the governor of Antioquia, Luis Pérez and the mayors of Ituango and Valdivia, explained that a scour was found.
This finding according to Maya Salazar occurred during the drilling work that was being done to close the gates of the powerhouse.
The manager indicated that two holes were made between the unloading tunnels 1 and 2 that connect to the machine house, “the first excavation was through rock and perfect, nothing was found. Then in the second perforation, not vertically but diagonally, at 30 or 40 meters there is a vacuum, which tells us that there is a scour”
My interpretation is that these are the tunnels that represent the water inlets to the turbines, which are located in a huge cavern, shown below:-
Two of these tunnels are currently allowing water to flow uncontrolled through the machine house (the others are intentionally blocked). To ascertain the damage there is a need to close these two open tunnels. Unfortunately, the exploratory drilling has found this large void between them. At the time of writing it was not clear to me as to whether this is a void made by the flow of water since the problems started, or it had been present from the start. Either way, this appears to be deeply problematic for the project.
Meanwhile, works are underway now to start to ascertain the level of damage to the powerhouse, induced when water flooded the tunnels in an uncontrolled manner last year. To this end, one of the two open gates (Gate 2) to the machine house will be closed today, with the second being closed in a few weeks time. It will be interesting to see what they find. Most of the dam has been evacuated, and warnings remain in place downstream. However, the operation is not considered by the authorities to be high risk.