Medellin-based power giant EPM announced December18 that it successfully closed the second of two massive flood-prevention doors in the “auxiliary diversion tunnel” (“GAD” in Spanish initials) at the US$5 billion, 2.4-gigawatt “Hidroituango” hydropower project.

The “GAD” had collapsed in April 2018, which forced EPM to divert Cauca River water through the dam’s machine room, causing hundreds of millions of dollars of losses from delays in power sales and related, temporary infrastructure damage -- for which the company is starting to receive substantial insurance compensation.

“EPM successfully completed the final maneuver of the closing of the [300-tons] second gate of the Auxiliary Diversion Gallery, GAD, after more than nine months of preparation and having closed the first gate on May 29,” according to the company.

“With the two gates properly closed, this pre-plugging of the GAD reduces the risks for the communities downstream of the dam works and enables the continuation of the recovery process of the Hidroituango hydroelectric project,” according to EPM.

The latest gate closure “allows the entry of personnel, machinery and other necessary resources,” while also enabling a planned pouring of a permanent concrete plug in the GAD during first-half 2020, according to the company.

Meanwhile, EPM continues to make progress toward plugging of the nearby “right diversion tunnel,” which also was damaged along a 400-meters-long stretch. This work includes construction of a new bypass channel due for completion by mid-2020, according to EPM.

“Once the GAD and the right diversion tunnel are technically plugged in mid-2020, any risk [of leakage or collapse]  will be reduced,” hence enabling Colombia’s National Disaster Risk Management Unit (UNGRD) to drop its existing "flood-warning" status-alert level to a relatively low level, EPM added.