In northern Brazil, the Belo Monte Dam complex on the Xingu River, a major tributary of the Amazon, has changed the course of the river and surrounding landscape. Construction began in 2011, and the complex began producing hydropower in 2016. When fully operational in 2018, it will have a maximum capacity of 11 gigawatts and be the world’s fourth largest hydropower plant. However, its annual average will be lower, about 4.5 gigawatts, because of seasonal low river flows.

Landsat’s shortwave infrared (SWIR) bands distinguish water and land. This band combination displays the rain forest as green, and faded green is deforestation. In the 2015 image, bright areas indicate construction of the dams, canal, and dikes to contain the reservoir.

The primary dam, Pimental, creates a reservoir along the river course, and a canal from that reservoir diverts 80 percent of the Xingu’s flow into another reservoir. The Belo Monte Dam and hydropower turbines are at the north end of this reservoir.

At the same time, these dams have caused the original flow path of the river to dry up, affecting fish and turtles that are unique to that stretch of the river. The thousands of people who live along the river and who depend on fishing for their livelihoods have also been affected by the river’s redirection.