Southern California’s Salton Sea is a prominent visual for astronauts.
This large lake supports the rich agricultural fields of the Imperial, Coachella
and Mexicali Valleys in the California and Mexico desert. The Salton Sea formed
by accident in 1905 when an irrigation canal ruptured, allowing the Colorado
River to flood the Salton Basin. Today the Sea performs an important function
as the sink for agricultural runoff; water levels are maintained by the runoff
from the surrounding agricultural valleys. The Salton Sea salinity is high—nearly
1/4 saltier than ocean water—but it remains an important stopover point
for migratory water birds, including several endangered species.
The region also experiences several environmental problems. The recent
increased demands for the limited Colorado River water threatens the amount of
water allowed to flow into the Salton Sea. Increased salinity and decreased
water levels could trigger several regional environmental crises.
The agricultural flow into the Sea includes nutrients and agricultural
by-products, increasing the productivity and likelihood of algae blooms. This
image shows either a bloom, or suspended sediment (usually highly organic) in
the water that has been stirred up by winds.
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.