The breaking of mining waste dam in Minas Gerais, in November, rekindled the discussion about the safety of this type of structure in the country, which number about 15,000, according to the National Water Agency. In the case of Itaipu, this issue is particularly relevant because it is one of the largest dams in the world; the cities of Foz do Iguaçu and Ciudad del Este are located on the banks of the Paraná River, a few kilometers downstream (below) of the plant; and because the reservoir is used to manage river floods , although under some limitations.

In the development of its activities, Itaipu takes into account the precautionary principle that is applicable to a single irreversible environmental risk: impairment of physical safety of the plant’s dam. While it is unlikely, the company is a worldwide reference in the field and had an outstanding performance in the creation of the Law 12.334/2010 establishing the National Policy on Dam Safety, and its regulations, which set a number of mechanisms and instruments that are adopted voluntarily by Itaipu. The plant also participates actively in the Brazilian Committee on Large Dams and the International Commission on Large Dams.

The safety of the dam is ensured by a comprehensive monitoring and maintenance program, under the responsibility of the Construction, Engineering, Maintenance and Operation Superintendents. The plant maintains a database with over 30 years of instrumentation readings and all technical drawings were scanned to allow quick access to information. When potential problems are identified, further studies are conducted, instrumentation is added, and/or maintenance protocols are modified.

The entity has more than 2,792 instruments to monitor the behavior of concrete structures and the foundation of their dams, and 5,295 drains to detect increased flow.

The most important instruments (about 10% of the total) are monitored on-line and feature a warning system where when abnormalities are detected, expert professionals are advised to take the necessary measures. The other instruments are read manually on a daily schedule and in periodic visual inspections.

The area around the reservoir has seismic monitoring since 1978, held for seven stations installed, and the results are analyzed with the support of the University of Brasília. The monitoring confirmed that the area has low natural seismicity and no movement induced by the reservoir was detected.

Another monitoring way is the hydrological monitoring, performed by an extensive network of hydrometeorological stations. The aim is to monitor the flow of water in various parts of the Paraná River and its tributaries upstream of the reservoir, so as to bring greater predictability, with reasonable advance to inflows of Itaipu, resulting in better reservoir level management and, therefore, dam safety, management of possible floods and the planning and optimization of energy production.

Created in 1975, the Board is a group of experts from different countries, with outstanding knowledge in engineering of large dams, hired by Itaipu to analyze the performance and measuring the degree of safety of the entire structure of the plant – especially the dam, by through technical inspections and analysis of data sent by employees. Frequent during construction, the consultancy has to take place every four years, and professionals are available for anytime counseling.

The last evaluation took place in November 2014 and the group found that the plant’s safety performance continues to be excellent, after 32 years of the first filling of the reservoir. The recommendations made by the consultants are deployed on a schedule, and several of them have already been met in 2015, such as performing a visual inspection of the dam using a modem system for robotic capture of digital images, incorporating cutting-edge technologies to the current Itaipu monitoring system.

Itaipu has binational management groups of the Emergency Action Plan (EAP), responsible for developing and maintaining updated action plans for identified contingencies, coordinate simulations performed according to an annual plan and training for professionals in a given emergency situation. The outsourced service providers participated in simulations and lectures on safety at the beginning of the services.

Itaipu serves as a model for other Brazilian hydroelectric companies. Representatives of Companhia Hidro Elétrica do São Francisco (Chesf), for example, have visited the binational to learn about their emergency action plans.The company has a fire brigade composed of 48 employees, who occasionally responds to emergencies in neighboring communities as in Paraguay, only the capital Asunción and Itaipu have professional brigades, while all others are voluntary. The brigade of Foz do Iguaçu was invited to visit the plant to be familiar with it if an emergency arises requiring the support of local firefighters.

In the year, two cases of unknown vessels which entered the reservoir security area have been recorded, causing joint action of interception by the Navy of Brazil, federal police and Corporate Security.

• Permanent Management Committee: coordinates the work of the groups.
• Technical Analysis Group: establishes the need to draw up a new plan.
• Simulation Management Group: promotes and systematically analyzes the drills.
• Contingency Analysis Group: nine subgroups elaborate and maintain plans updated.

As a plant to the trickle of water, i.e. without sensitive capacity to change the quota of its reservoir, Itaipu has reduced damping capacity of the floods, which thereby are propagated downstream, following its natural course along the Paraná River. The company maintains a full committee to monitor the situation based on the inflow of water it receives from hydropower plants upstream and rains located on Itaipu reservoir and its contribution basin.

This committee, among other duties, is responsible for reporting, with as much as advance notice as possible, the sectors responsible for the dissemination of hydrological situation for bodies in Brazil and Paraguay, especially the Civil Defense, to carry out evacuation of some low-lying areas, if necessary.

There were two flood events in 2015. The first occurred in July, resulting in the issuance of 13 hydrological warning bulletins for the institutions that provide assistance to coastal communities, including the Civil Defense of the two countries. In November 2015, there was a new, more persistent flood, which kicked only in late March 2016. It rained very much upstream (above) and downstream (below) of the plant, thus increasing the level of the Iguaçu River, where are the Falls and the Paraná River, where Itaipu is located. The three spillway chutes were open – which has not happened for four years. 72 hydrologic warning bulletins were issued.

In both events there was the need for evacuation of residents from San Rafael neighborhood, located in Paraguay; 5 families during the flood in July and 62 in November. In Brazil, only the port facility in the neighborhood of Porto Meira was affected.