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At the heart of Itaipu: rappelling to rescue fish
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23/03/2009

A span 11 meters across and 18 meters high was the workplace of technician Cícero Medeiros da Silva, from the Reservoir Division (MARR.CD, in Portuguese) Wednesday (18) at the inspection of generator unit 07. His job: going down those 18 meters and rescue fish from the suction tube right at the turbine outlet.

 

Their efforts started the day before as the SMMU.DT crew set up a platform right below the turbine. For this team’s safety, the suction tube is not entirely drained – in case an employee falls, their dive is cushioned by the water and they are protected by life vests. 

 

Incidentally, the Labor Safety department closely monitors the entire maintenance of the unit. There are two Brazilian technicians and two Paraguayans especially deployed for the job on the U07. They know exactly which activities require more attention.

 

But then we go back to technician Cícero, who at this point is already going down the suction tube in search of fish. After the platform is assembled, the water in the tube is nearly all drained, there remaining only a shallow film of water to keep the fish alive.

 

In a cage, Cícero has slowly descended in the suction tube under guidance from Sandro Heil, also from MARR.CD. Besides the protection provided by a steel cable, the activity also includes a backup system – another cable is fastened to the technician, a required safety redundancy.

 

Cícero also needed to be in great health conditions and get special training for high altitude work. “When someone goes down the chute they may panic and freeze”, said labor safety technician Wilmar Camilo, from the Labor Safety Engineering Division (RHSS.AD, in Portuguese). Safety equipment also includes a hard hat, leather gloves and waterproof boots.

 

Back to the lake

 

It was slim pickings – just eight fish, among armados, mandis and jaús. According to the crew, that is common for a generator located to a more central area at the dam. Fish migration takes place preferably through the sides, where water speeds are lower.

 

The fish rescued are released back to their place of origin: the Itaipu reservoir. The same work was also performed upstream from the dam, between the maintenance and the stop-log gates. There have been 500 rescue operations since 1987, with something like 50,000 fish recovered. A fun fact: the largest specimen saved so far was a 50-kilo jaú (Zungaru zungaru).