Earthshots: Satellite Images of Environmental Change

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» Iguazú, South America

On the border between Brazil, Paraguay, and Argentina are some curious land use features. Paraguay lies west of the Paraná River, which runs north to south down the middle of the images. The Iguazú River flows toward the west and into the Paraná River. North of the Iguazú River is Brazil, and Argentina is to its south.

At this location, we can see the effects of deforestation of the rain forest, one of the largest dams in the world, a spectacular set of waterfalls, and a sharp contrast between protected land and intense development.

Map of the featured area.

Within this scene is one of the largest waterfalls in the world. On the border between Brazil and Argentina on the Iguazú River, 275 falls collectively make up Iguazú Falls. “Devil’s Throat” is the tallest at 80 meters.

Landsat’s 30-meter resolution doesn’t reveal the falls in great detail. But in the 2011 image, a blue-white line at the location of the falls points down toward the southeast. This line is the foamy water crashing over the Devil’s Throat portion of the falls.

A runway is visible southwest of the falls. This is Cataratas Airport, which serves the city of Puerto Iguazú, Argentina, and provides access for tourists to visit the falls.

Iguazú Falls was named one of the New 7 Wonders of Nature in 2011.

Iguazú National Park is located in Argentina on the border with Brazil and Paraguay. Its boundary is sharply defined as the bright green section on the right of the images. The Brazilian side of the park, north of the Iguazú River, is called Iguaçú National Park.

The park is almost an island of southwestern Atlantic rain forest, one of the few remaining original areas of this type of tropical rain forest. The Atlantic rain forest is distinct from the Amazon and once stretched along most of Brazil’s Atlantic Coast and inland several hundred kilometers. In 1973, there were some cleared areas just north of the Iguazú River in Brazil, but they have since regrown.

These images clearly demonstrate the effect of differing land use policies surrounding the park. Paraguay lies west of the Paraná River, which runs vertically through the center of these scenes. Paraguay has permitted complete development of the land. In 1973, the area seen in these images was vegetated, but by 2011, nearly all the land on the Paraguay side appears to be under human development, with a patchwork of cleared and agricultural areas.

The deforestation in Paraguay begins with the telltale fishbone pattern. Roads built into the forest are the entryway into clearing the land for agriculture. On the Argentina side of the river, development is considerably more modest than in Paraguay. The bottom middle part of these images shows a different forest management practice. The oddly shaped patterns of deep green are forest plantations used for lumber and pulp. While intense transition from forest to agriculture can harm the land and environment, these plantations can reduce soil erosion, improve water quality, increase carbon sequestration, and provide habitat for many species.

The world’s largest hydroelectric power plant is on the Paraná River between Paraguay and Brazil. The Itaipú Dam is capable of producing 14,000 megawatts of power. The reservoir behind the dam formed in 1982 and covers 1,350 square kilometers.

The entire dam is nearly 8 kilometers long. The maximum discharge capacity of the spillway is 62,200 cubic meters per second, 40 times the mean discharge of Iguazú Falls.

Just below the dam is the rapidly expanding city of Ciudad del Este. Its estimated population in 2015 was 317,525.


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