Columbia’s troubled Hidroituango hydroelectric dam project has hit further problems after a significant scouring was discovered in the rock mass close to the dam.
Construction of the dam was fast tracked and then halted several times in May and June last year due to concerns over stability of the dam and risk of overtopping following a number of upstream landslides.
Dam owner Empresas Públicas de Medellín (EPM) said in a press conference that the new problem was discovered during drilling work within the dam structure itself to ascertain damage caused when the powerhouse was flooded last year.
EPM project manager Jhon Maya Salazar said that the void was discovered when two bores were being made between the discharge tunnels that connect to the machine house. “The first excavation was through rock and perfect, nothing was found,” he said. “Then in the second there was perforation, not vertically but diagonally, and at 30m or 40m there is a vacuum, which tells us that there is a scour.”
Water was flowing uncontrolled through these two tunnels while the other outlets have not been opened but it is not clear if the water flow has caused the scour or if it was a pre-existing defect in the rock mass.
Waterflow in one of the tunnels has been shut off and work is underway to close the second tunnel to allow for further investigation. EPM said that there had been minimal ground movement following closure of the tunnel but ground movements are being monitored ahead of clsure of the second tunnel.
The dam site has been evacuated and downstream warning have been put in place until the investigation is concluded.