Three towns were evacuated downstream from Colombia’s largest dam on Monday amid fears that the unexpected release of a valve could cause flash floods.
The towns of Valdivia, Taraza and Caceres in Antioquia could be under serious danger with reports water began to leak from one of the dam’s previously plugged tunnels of the troubled Ituango hydroelectric dam project.
Although the Unified Command Post (PMU) reported that water flow is moderate, the full unblocking of the tunnel could increase to a critical 6,000 cubic meters per second, threatening to flood nearby towns.
According to the company in charge of the dam’s construction, Medellin public services firm EPM, “more than 90% of residents have been evacuated” from the three towns under serious threat. Residents in Nechi and Caucasia, which are on orange alert, should remain attentive to what authorities and aid agencies advise.
Until now, the PMU reports around 8,000 people in total have been evacuated from areas surrounding the troubled dam, with a further 112,000 residents across 17 municipalities believed to be at risk.
Relief efforts faced a major setback over the weekend with overflowing water filtering out of the dam at only half capacity after the blocking of the provisional valve, Medellin Mayor Federico Gutierrez told media.
Gutierrez explained that progress to safely discharge the tons of cubic meters of water being built up in the engine room was being stalled, apparently due to a blockage in two of the exit valves.
According to Gutierrez, water levels of the reservoir rose at 20 centimeters per hour, meaning the dam may overflow within days.
The height of the dam’s walls is sitting at 407 meters, with workers racing against the clock to get to the intended height of 410 meters, according to EPM. This would allow water to flow through the penstock and would allow the closing of the provisional tunnels.
The National Unit for Disaster Risk Management recommended to residents that live along the banks of the Cauca River to remain vigilant, seek updated information on the situation and adhere to preventative measures.
An envoy of international advisers arrived in Ituango on Sunday and Monday to assist local teams on how best to avoid a catastrophe. The experts in hydroelectric engineering will seek to find a solution to reroute water that’s building up in the engine room, which would eventually led to the dam’s collapse.
Colombia’s Prosecutor General’s Office said on Friday that it has begun criminal investigations against EPM.