Only 4% of Brazil's dams were inspected for safety by supervisory bodies between October 2014 and September 2015, according to the results of the latest dam safety report conducted by national water authority ANA.
The report considers the 12-month period immediately preceding the catastrophic tailing dam collapse of Brazilian pellet producer Samarco last November in Minas Gerais state.
Besides the lack of inspections, a number of other worrying findings were made. Among them is the high potential of unknown risks in most of the dams and an overall lack of information.
Of the 17,259 dams registered in the country, 79% of them had no definite information on their height and 45% had no specific data on their volume. Moreover, 6,055 dams (about 35%) had no information of the business entity responsible for them, according to the report.
Of the 701 dams that were actually inspected, 73% were located in just two states; São Paulo and Rio Grande do Sul, ANA said.
In conclusion, a total of 2,368 dams (13%) were classified as being at risk and 2,224 (12%) were considered to have associated damage potential.
"Dam supervisors and regulators do not have adequate staff to implement Brazil's national dam safety policy, PNSB. However, we are expecting a restructuring that will eventually meet these needs," said ANA regulation superintendent Rodrigo Flecha.
Goiás state's Joao Leite reservoir and dam (CREDIT: Saneago).
There are four types of dams in Brazil, namely those for containment of industrial waste, containment of mining waste, hydroelectric power generation and for multiple water use. The number of dams in the report was 15% higher than was recorded the previous year, when 14,966 such facilities were registered.
Brazil has a total of 43 supervisory bodies regulating the sector, according to the report.