Explosions Rock Santo Antônio Dam in Brazilian Amazon

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Fire rips through the Santo Antônio Dam on Brazil's Madeira River after an explosion on October 18th.

Fire rips through the Santo Antônio Dam on Brazil’s Madeira River after an explosion on October 16th.
Rondônia Agora

Early this morning, explosions ripped through the Santo Antônio Dam on Brazil’s Madeira River, one of two hydroelectric dams that have recently begun operation in this Amazon frontier region.

A representative of the Instituto Madeira Vivo reported that a breaker box exploded, precipitating a fire on the dam that injured one man and woman. In a separate report, the daily Rondônia Agora had earlier claimed that one turbine had exploded, killing one and injuring several others. Santo Antônio Energia workers have cordoned off the site, disallowing journalists from obtaining detailed information.

While an investigation ensues, the explosion reminds us that dams on the Madeira River, including the existing Santo Antônio and Jirau dams plus at least an additional two dams planned upstream, will suffer safety and operational risks due to the nutrient balance of the Amazon’s most heavily-sedimented river basin. 

The Madeira, Bení, and Madre de Dios rivers in Brazil, Bolivia and Peru carry nutrient-rich sediments down from the Andes mountains and transport them to the Amazon mainstem. The mainstem accumulates sediments from across the basin and moves them to the Amazon Delta near the Island of Marajó on coastal Brazil, where they’re distributed into the Atlantic Ocean. Researchers have illustrated how sediments play a vital role in replenishing ocean lifeforms, and have studied how they may aid in regulating the ability of the ocean to absorb carbon.

Satellites have captured photos of the "Amazon Plume," a wide fan of sediment pouring out of the basin system into the Atlantic Ocean.

Satellites have captured photos of the “Amazon Plume,” a wide fan of sediment pouring out of the basin system into the Atlantic Ocean.

Dams on the Madeira River not only disrupt these larger ecosystem functions, they also present operational and safety risks at each dam site. Dams built on such brown, murky rivers accumulate sediment very quickly in their reservoirs, creating troublesome water quality impacts. Nutrient loading can produce Hydrogen Sulfide, which can corrode turbines and make them inoperable, leading to electrical failures. This has happened recently with the infamous Bakun Dam in Sarawak, Malaysia, as its reservoir has received high amounts of run-off from surrounding palm oil plantations. As recently as May, two of Bakun’s four turbines had been rendered inoperable.

The Santo Antônio and Jirau dams were designed as “run-of-the-river” dams to attempt to avoid such problems, but the enormous scale of their reservoirs (despite the rhetoric, run-of-the-river dams still produce reservoirs) and the sheer volume of sediment traveling down the Madeira will continue to present enormous challenges to operational efficacy.

It is as of yet unconfirmed whether accumulated sediments indeed played the defining role in this explosion and apparent turbine failure at Santo Antônio. Nonetheless, the disaster serves as a warning to Ministries of Energy who are hunting for dam sites: where there is sediment, there are risks, and risks create costs.