Stuff You Should Know

Eco-Disasters 101: The Salton Sea

November 11, 2025

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  • The Salton Sea, an inland body of water in Southern California, was accidentally created in 1905 when an engineering error diverted the Colorado River into the Salton Basin, leading to a temporary 400-square-mile body of water. 
  • Initially, the Salton Sea became a thriving recreational area and wildlife refuge due to agricultural runoff providing fish and attracting migratory birds, despite the water quickly becoming saltier than the Pacific Ocean. 
  • The Salton Sea is now a severe ecological disaster, shrinking due to lack of inflow, concentrating toxins from agricultural runoff, and creating hazardous dust that is linked to increased respiratory health issues in the surrounding population. 

Segments

Salton Sea Geological History
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(00:05:24)
  • Key Takeaway: Geological evidence shows cyclical formation of inland seas in the Salton Basin dating back 40,000 years, caused by the Colorado River flooding into the trough.
  • Summary: The Salton Basin is a large geological trough that historically filled with water from the Colorado River during periods of high flow. This process occurred cyclically for millennia, with previous lakes, like Lake Cahuila, sometimes reaching 26 times the size of the current Salton Sea. Silt carried by the river would eventually clog the outlet, allowing the lake to dry up through evaporation.
Accidental Creation of the Sea
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(00:09:44)
  • Key Takeaway: The modern Salton Sea was formed when an improperly constructed temporary bypass canal for the Imperial Canal failed catastrophically due to heavy rains and snowmelt in 1905.
  • Summary: The Imperial Canal was built in the early 1900s to irrigate the rich desert soil using Colorado River water. When the original canal clogged with silt, a temporary bypass was dug without proper headgates to control flow. Abnormal weather caused the Colorado River to overwhelm this temporary channel, redirecting its course into the Salton Basin for two years until the breach was sealed in 1907.
Initial Boom and Wildlife Refuge
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(00:18:26)
  • Key Takeaway: Agricultural runoff, which stabilized the lake by replacing evaporated water, turned the initially freshwater Salton Sea into a saltwater environment that attracted significant bird migration.
  • Summary: The lake stabilized because agricultural irrigation runoff, rich in salt, continuously fed the basin, making the water saltier than the ocean over time. This new water source attracted birds along the Pacific Flyway, leading to the creation of the Salton Sea Wildlife Refuge by the 1930s. The area was developed into a resort destination known as the California Riviera, featuring celebrities and speedboat races.
Ecological Collapse and Die-Offs
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(00:23:30)
  • Key Takeaway: Eutrophication from fertilizer runoff and high summer heat in the increasingly saline, landlocked water led to massive fish and bird die-offs, including 8 million tilapia in one day in 1999.
  • Summary: The lack of an outlet meant that pesticides and fertilizers from agriculture concentrated in the warm water, causing toxic algae blooms that depleted oxygen and created dead zones. Fish suffocated annually due to warm, briny water holding less oxygen, leading to catastrophic bird die-offs, including one of the largest recorded losses of endangered brown pelicans.
Current Health and Financial Threats
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(00:40:35)
  • Key Takeaway: As the Salton Sea evaporates, the exposed, toxic lakebed turns into dust, causing an uptick in asthma rates among local children, with the total financial toll projected to reach $70 billion.
  • Summary: The shrinking lake concentrates toxins like DDT and heavy metals, which are then blown into the air as particulate matter affecting the 650,000 people in the region. Researchers have linked this dust exposure to increased asthma rates in elementary school children in the Imperial Valley. Financial estimates suggest the environmental catastrophe could cost up to $70 billion over 30 years through lost property values and public health burdens.
Recent Restoration Efforts and Future Plans
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(00:46:37)
  • Key Takeaway: Recent state and federal funding has provided nearly half a billion dollars to restore wetlands, significantly accelerating conservation efforts compared to previous decades of inaction.
  • Summary: After years of failed funding attempts, California and the federal government recently committed substantial funds toward restoring parts of the Salton Sea into wetlands for bird habitat. This funding surge allows for the restoration of thousands of acres, moving beyond previous minimal efforts. Future economic possibilities in the area include geothermal electricity generation and lithium mining from the lakebed.