Dividing up water resources in southern California is always a controversial activity. Water allocations for the agriculture in the Imperial Valley, the Salton Sea, and the expanding urban and residential growth in San Diego County were in limbo until a recent agreement was drafted, allowing San Diego to buy conserved Colorado River water from the Imperial Valley. This astronaut photograph details an algal bloom in the Salton Sea, where such blooms continue to be a problem. They are caused by high concentrations of nutrients, especially nitrogen and phosphorous, that drain into the basin from the agricultural run-off. As the algae dies and decomposes, oxygen levels in the sea drop, causing fish kills and hazardous conditions for other wildlife.
Along the border of Mexico and the U.S., a geologically and tectonically complex area serves as a visual reference point for astronauts on the International Space Station.
Once the world’s fourth largest lake, the rapidly shrinking Aral Sea has fragmented into four bodies of water. The Southern Aral Sea and Tsche-Bas Gulf show the most dramatic change in 2011.
This view shows the sun reflecting off the surface waters that surround the spit that defines the Zaliv Kara-Bogaz-Gol from the open Caspian Sea. The sunglint reveals the flow of fresher water through the spit channel and into the bay.
The arrow-shaped island in the Aral Sea used to be a 35-kilometer-long visual marker, indicating the Aral Sea to astronauts. An image from the present International Space Station increment shows how much the coastline has changed as the sea level has dropped during the last three decades.
The Aral Sea has shrunk to less than half its size since 1985. It receives little water (sometimes none) from the two major rivers that empty into it—the Syr Darya and Amu Darya. Instead, the river water is diverted to support irrigation for the region’s extensive cotton fields. Recently, water scarcity has increased due to a prolonged drought in Central Asia. As the Aral Sea recedes, its former seabed is exposed. The Aral’s sea bed is composed of fine sediments—including fertilizers and other agricultural chemicals—that are easily picked up by the region’s strong winds, creating thick dust storms. The International Space Station crew observed and recorded a large dust storm blowing eastward from the Aral Sea in late June 2001. This image illustrates the strong coupling between human activities (water diversions and irrigation), and rapidly changing land, sea and atmospheric processes—the winds blow across the Sea and pick up dust (former sea bottom sediments) as soon as the blowing air masses hit land.