Salton Sea

The Salton Sea is a shallow, landlocked body of water that has a high concentration of salts in Riverside and Imperial counties, on the San Andreas Fault at the southern end of the U.S. state of California. It lies within the Salton Trough that stretches to the Gulf of California in Mexico. Over millions of years, the Colorado River has flowed into the Imperial Valley and deposited alluvium (soil), creating fertile farmland, building up the terrain, and constantly moving its main (or only) river delta. For thousands of years, the river has alternately flowed into and out of the valley, creating a freshwater lake or an increasingly saline lake, and a dry desert basin, respectively, depending on river flows and the balance between inflow and evaporative loss. Hundreds of archaeological sites have been found, indicating possibly long-term Native American villages and temporary camps.

The lake was created by inflow of water from the Colorado River in 1905. Beginning in 1900, an irrigation canal was dug from the Colorado River to the old Alamo River channel to provide water to the Imperial Valley for farming. The headgates and canals suffered silt buildup, so a series of cuts was made in the bank of the Colorado River to further increase the water flow. Water from spring floods broke through a canal head-gate diverting a portion of the river flow into the Salton Basin for two years before repairs were completed. The water in the formerly dry lake bed created the modern lake that is about 15 by 35 miles.

The lake would have dried up, but farmers used generous amounts of Colorado River water and let the excess flow into the lake. In the 1950s and into the '60s, the area became a resort destination, and communities grew with hotels and vacation homes. Birdwatching was also popular as the wetlands were a major resting stop on the Pacific Flyway.

In the 1970s, scientists issued warnings that the lake would continue to shrink and become more inhospitable to wildlife. In the 1980s, contamination from the farm runoff promoted the outbreak and spread of diseases. Massive die-offs of the avian populations have occurred, especially after the loss of several species of fish on which they depend. Dead fish would wash up on the shore as the lake became so salty that large fish kills occurred. Tourism was drastically reduced.

After 1999, the lake began to shrink as local agriculture used the water more efficiently so less runoff flowed into the lake. As the lake bed became exposed, the winds sent clouds of toxic dust into nearby communities where Latinos make up the majority of the population. Smaller amounts of dust reached into the Los Angeles area and people there could sometimes smell an odor coming from the lake. The state is mainly responsible for fixing the problems, as California lawmakers pledged to fund air-quality management projects in conjunction the signing of the 2003 agreement to send more water to coastal cities. Local, state, and federal bodies had found minimal success dealing with the dust, dying wildlife, and other problems for which warnings had been issued decades before. As 40% less water began flowing into the lake at the beginning of 2018 and local agencies declared a health emergency due to the dust, the state minimally funded and developed the Salton Sea Management Program. After a slow start and some small projects, construction started on a $206.5 million project in early in 2021 on the delta of the New River, building ponds and wetlands on the highly polluted river situated at the southern bank of the lake.

In 2020, Palm Springs Life magazine summarized the ecological situation as "Salton Sea derives its fame as the biggest environmental disaster in California history".