Environmental Issues Affecting Salton Sea, USA33.2N 115.9W
The Salton Sea (the pear-shaped lake in the upper left quadrant) was formed by the joint forces of humans and nature about 100 years ago when the turbulent Colorado River breached the levee of an early irrigation diversion channel and flooded the low-lying desert of Imperial and Riverside counties.
According to the Water Education Association, although it was once California’s largest fresh water lake, the 360-square mile Salton Sea today is saltier than the Pacific Ocean. Without a natural outlet, water trapped more than 200 feet below sea level in this massive desert sink continually evaporates, increasing the salt content in the remaining water and threatening the sea’s fishery. It is a natural process; one embodied in the highly saline Great Salt Lake in Utah and the Dead Sea of the Middle East.
Under natural conditions the Salton Sea might well have evaporated by now, following the course set by Ancient Lake Cahuilla, if it weren’t for artificial inflow from agricultural drainage, storm runoff and wastewater discharges from Mexico and California.
Yet in an ironic twist, this vital supply of water that empties to the sea–showing the rate of salinity increase and sustaining its wildlife–also causes problems. Salt, selenium and pesticides are carried into the sea with agricultural return flows, which originate largely from Imperial Valley farms.
Attention also has focused on the poor quality of water in the New River at the Mexico-California boundary, although there is some controversy over whether pollutants that originate in Mexico or California are the greatest threat to the sea itself and the wildlife of the area.