As can be seen in the presented satellite images with a difference of 17 years, the right tributary of the Amazon - the Xingu River - has changed significantly over the past years. And this change is exclusively human in nature.
The image on the left was acquired on May 26, 2000 using the Enhanced Thematic Mapper Plus multispectral scanner on the Landsat-7 satellite. The site chosen for the construction of the Belo Monti hydroelectric complex in northern Brazil is visible. At that time, the river was still flowing freely along its bed. The project was first reviewed in the 1970s, but construction did not begin until 2011.
By early 2016, after the first Pimental Dam was built on the Xingu River, water formed the main reservoir. Turbines soon started operating, and by April 2016, electricity was supplied to the grid. The complex now consists of numerous dams, canals and power plants.
The image on the right, taken on July 20, 2017 with the OLI instrument on the Landsat-8 satellite, shows what this site looks like now.
The water in the Xingu River usually flows north to the Amazon, but at first it temporarily sinks south and follows a 100-kilometer bend in the Volta Grande region. Now only about 20% of the original river flow travels along this bend.
The decrease in water volume in this area has led to the appearance of new dry areas, indicated in brown. The drainage, in turn, influenced the lives of unique aquatic life and local indigenous tribes.
In addition, the images show significant changes in the amount of forest and agricultural land. Some of the newly flooded areas have been deforested, according to analysts at the Monitoring of the Andean Amazon Project (MAAP).
Due to the dam, 80% of the flow is now diverted to the main tank, from where it flows through the channel to the second tank. The right image allows you to see in detail the main reservoir and part of the canal. The new flooded areas cover about 200 square kilometers, according to estimates by MAAP experts.
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When fully operational in 2018, Belo Monti will have a maximum capacity of 11,233 megawatts, making it the fourth largest hydropower plant in the world. The actual electricity generated will, on average, be much smaller - about 4,500 megawatts. But the project is expected to help meet Brazil's energy needs and boost its economic growth.