Native to the tropics of South America, the water hyacinth now thrives on every continent except Europe. It was introduced in Africa around 1879, and 110 years later, established itself on the continent’s largest lake, Lake Victoria.
Acquired on April 10, 2010, and and March 7, 2009, these natural-color images show changes in a central Australian saltpan, Lake Frome. In 2010, water has seeped into the salt lake, leaving standing water in some areas and muddying much of the ground surface.
Ongoing drought and diminished snowpack in the Rockies have combined with increasing demands downstream to cause the great reservoir to drop to historically low levels.
In spring 2014, visitors to Lake Powell will find beaches and rock formations that are usually underwater. After several years of drought, the reservoir has dropped below 50 percent capacity.
For more than 100 years, groups in the western United States have fought over water. During the 1880s, sheep ranchers and cattle ranchers argued over drinking water for their livestock on the high plains. In 1913, the city of Los Angeles began to draw water away from small agricultural communities in Owen Valley, leaving a dusty dry lake bed. In the late 1950s, construction of the Glen Canyon Dam catalyzed the American environmental movement. Today, farmers are fighting fishermen, environmentalists, and Native American tribes over the water in the Upper Klamath River Basin. The Landsat 7 satellite, launched by NASA and operated by the U.S. Geological Survey, documented an extreme drought in the area along the California/Oregon border in the spring of 2001.
The Great Salt Lake of northern Utah is a remnant of glacial Lake Bonneville that extended over much of present-day western Utah and into the neighboring states of Nevada and Idaho approximately 32,000 to 14,000 years ago. The north arm of the lake, displayed in this astronaut photograph from April 30, 2007, typically has twice the salinity of the rest of the lake due to impoundment of water by a railroad causeway that crosses the lake from east to west. The causeway restricts water flow, and the separation has led to a striking division in the types of algae and bacteria found in the north and south arms of the lake.